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src/magazine_malloc.c libmalloc-53.30.1 libmalloc-317.121.1
--- libmalloc/libmalloc-53.30.1/src/magazine_malloc.c
+++ libmalloc/libmalloc-317.121.1/src/magazine_malloc.c
@@ -24,6139 +24,87 @@
 /* Author: Bertrand Serlet, August 1999 */
 
 /*
- Multithread enhancements for "tiny" allocations introduced February 2008.
- These are in the spirit of "Hoard". See:
- Berger, E.D.; McKinley, K.S.; Blumofe, R.D.; Wilson, P.R. (2000).
- "Hoard: a scalable memory allocator for multithreaded applications".
- ACM SIGPLAN Notices 35 (11): 117-128. Berger2000.
- <http://portal.acm.org/citation.cfm?id=356989.357000>
- Retrieved on 2008-02-22.
+ * Multithread enhancements for "tiny" allocations introduced February 2008.
+ * These are in the spirit of "Hoard". See:
+ * Emery D. Berger, Kathryn S. McKinley, Robert D. Blumofe, and Paul R. Wilson. 2000.
+ * Hoard: a scalable memory allocator for multithreaded applications.
+ * In Proceedings of the ninth international conference on Architectural support for
+ * programming languages and operating systems (ASPLOS IX).
+ * ACM, New York, NY, USA, 117-128.
+ * DOI: https://doi.org/10.1145/378993.379232
+ * Retrieved on 2008-02-22.
  */
 
-/* gcc -g -O3 magazine_malloc.c malloc.c -o libmagmalloc.dylib -I. \
- -I/System/Library/Frameworks/System.framework/PrivateHeaders/ -funit-at-a-time \
- -dynamiclib -Wall -arch x86_64 -arch i386 -arch ppc */
-
-#include <TargetConditionals.h>
-
-#include "scalable_malloc.h"
-#include "malloc_printf.h"
-#include "malloc_internal.h"
-#include "magmallocProvider.h"
-
-#include <_simple.h>
-#include <errno.h>
-#include <signal.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <unistd.h>
-#include <libkern/OSAtomic.h>
-#include <mach/vm_statistics.h>
-#include <mach/mach_init.h>
-#include <os/tsd.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <sys/param.h>
-
-#if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__arm64__)
-#define __APPLE_API_PRIVATE
-#include <machine/cpu_capabilities.h>
-#define _COMM_PAGE_VERSION_REQD 9
-#undef __APPLE_API_PRIVATE
+#include "internal.h"
+
+#if DEBUG_MALLOC
+#define LOG(szone, ptr) (szone->log_address && (((uintptr_t)szone->log_address == -1) || (szone->log_address == (void *)(ptr))))
 #else
-#include <sys/sysctl.h>
-#endif
-
-#include <libkern/OSAtomic.h>
-#include <mach-o/dyld.h>	/* for NSVersionOfLinkTimeLibrary() */
-#include <mach-o/dyld_priv.h>	/* for _dyld_get_image_slide() */
-#include <crt_externs.h>	/* for _NSGetMachExecuteHeader() */
-#include <mach/vm_param.h>
-#include <mach/mach_vm.h>
-#include <sys/vmparam.h>
-#include <os/tsd.h>
-
-#include <mach/vm_page_size.h>
-
-#define trunc_page_quanta(x) (vm_page_size >= vm_kernel_page_size ? trunc_page((x)) : trunc_page_kernel((x)))
-#define round_page_quanta(x) (vm_page_size >= vm_kernel_page_size ? round_page((x)) : round_page_kernel((x)))
-#define vm_page_quanta_size MAX(vm_page_size, vm_kernel_page_size)
-#define vm_page_quanta_shift MAX(vm_page_shift, vm_kernel_page_shift)
-
-#ifndef PAGE_MAX_SIZE
-/* Until xnu exposes these publically in mach/vm_param.h ... */
-
-#define PAGE_MAX_SHIFT      14
-#define PAGE_MAX_SIZE       (1 << PAGE_MAX_SHIFT)
-#define PAGE_MAX_MASK       (PAGE_MAX_SIZE-1)
-
-#define PAGE_MIN_SHIFT      12
-#define PAGE_MIN_SIZE       (1 << PAGE_MIN_SHIFT)
-#define PAGE_MIN_MASK       (PAGE_MIN_MASK-1)
-
-#endif
-
-#include <CrashReporterClient.h>
-
-/*********************	DEFINITIONS	************************/
-
-#define DEBUG_MALLOC			0 // set to one to debug malloc itself
-
-#define DEBUG_CLIENT			0 // set to one to debug malloc client
-
-#define DEBUG_MADVISE			0
-
-// <rdar://problem/10397726>
-#define RELAXED_INVARIANT_CHECKS 1
-
-#if TARGET_OS_EMBEDDED
-# define MADVISE_PRESSURE_RELIEF 0
-#else
-// <rdar://problem/12596555>
-# define MADVISE_PRESSURE_RELIEF 1
-#endif
-
-#if DEBUG_MALLOC
-#warning DEBUG_MALLOC ENABLED
-# define INLINE
-# define ALWAYSINLINE
-# define CHECK_MAGAZINE_PTR_LOCKED(szone, mag_ptr, fun)				\
-	do {										\
-		if (TRY_LOCK(mag_ptr->magazine_lock)) {			\
-			malloc_printf("*** magazine_lock was not set %p in %s\n",		\
-			mag_ptr->magazine_lock, fun);						\
-		}										\
-	} while (0)
-#else
-# define INLINE	__inline__
-# define ALWAYSINLINE __attribute__((always_inline))
-# define CHECK_MAGAZINE_PTR_LOCKED(szone, mag_ptr, fun)	{}
-#endif
-
-# define NOINLINE __attribute__((noinline))
-
-#if defined(__i386__) || defined(__x86_64__)
-#define CACHE_LINE 128 /* Future-proofing at 128B */
-#elif defined(__arm__) || defined(__arm64__)
-#define CACHE_LINE 64
-#else
-#define CACHE_LINE 32
-#endif
-#define CACHE_ALIGN __attribute__ ((aligned (CACHE_LINE) ))
-
-#if !__LP64__
-#define ASLR_INTERNAL			1
-#endif
-
-#define SCRIBBLE_BYTE			0xaa /* allocated scribble */
-#define SCRABBLE_BYTE			0x55 /* free()'d scribble */
-#define SCRUBBLE_BYTE			0xdd /* madvise(..., MADV_FREE) scriblle */
-
-/*
- * msize - a type to refer to the number of quanta of a tiny or small
- * allocation.  A tiny block with an msize of 3 would be 3 << SHIFT_TINY_QUANTUM
- * bytes in size.
- */
-typedef unsigned short msize_t;
-
-typedef union {
-	void	*p;
-	uintptr_t	u;
-} ptr_union;
-
-typedef struct {
-	ptr_union	previous;
-	ptr_union	next;
-} free_list_t;
-
-typedef unsigned int grain_t; // N.B. wide enough to index all free slots
-
-typedef int mag_index_t;
-
-#define CHECK_REGIONS			(1 << 31)
-#define DISABLE_ASLR			(1 << 30)
-
-#define MAX_RECORDER_BUFFER		256
-
-/*********************	DEFINITIONS for tiny	************************/
-
-/*
- * Memory in the Tiny range is allocated from regions (heaps) pointed to by the
- * szone's hashed_regions pointer.
- *
- * Each region is laid out as a heap, followed by a header block, all within
- * a 1MB (2^20) block.  This means there are 64520 16-byte blocks and the header
- * is 16138 bytes, making the total 1048458 bytes, leaving 118 bytes unused.
- *
- * The header block is arranged as in struct tiny_region defined just below, and
- * consists of two bitfields (or bit arrays) interleaved 32 bits by 32 bits.
- *
- * Each bitfield comprises NUM_TINY_BLOCKS bits, and refers to the corresponding
- * TINY_QUANTUM block within the heap.
- *
- * The bitfields are used to encode the state of memory within the heap.  The header bit indicates
- * that the corresponding quantum is the first quantum in a block (either in use or free).  The
- * in-use bit is set for the header if the block has been handed out (allocated).  If the header
- * bit is not set, the in-use bit is invalid.
- *
- * The szone maintains an array of NUM_TINY_SLOTS freelists, each of which is used to hold
- * free objects of the corresponding quantum size.
- *
- * A free block is laid out depending on its size, in order to fit all free
- * blocks in 16 bytes, on both 32 and 64 bit platforms.  One quantum blocks do
- * not store their size in the block, instead relying on the header information
- * to determine their size.  Blocks of two or more quanta have room to store
- * their size in the block, and store it both after the 'next' pointer, and in
- * the last 2 bytes of the block.
- *
- * 1-quantum block
- * Offset (32-bit mode)	(64-bit mode)
- * 0x0          0x0      : previous
- * 0x4          0x08     : next
- * end          end
- *
- * >1-quantum block
- * Offset (32-bit mode)	(64-bit mode)
- * 0x0          0x0      : previous
- * 0x4          0x08     : next
- * 0x8          0x10     : size (in quantum counts)
- * end - 2      end - 2  : size (in quantum counts)
- * end          end
- *
- * All fields are pointer-sized, except for the size which is an unsigned short.
- *
- */
-
-#define SHIFT_TINY_QUANTUM		4	// Required for AltiVec
-#define	TINY_QUANTUM			(1 << SHIFT_TINY_QUANTUM)
-
-#define FOLLOWING_TINY_PTR(ptr,msize)	(((unsigned char *)(ptr)) + ((msize) << SHIFT_TINY_QUANTUM))
-
-#ifdef __LP64__
-#define NUM_TINY_SLOTS			64	// number of slots for free-lists
-#else
-#define NUM_TINY_SLOTS			32	// number of slots for free-lists
-#endif
-
-#define NUM_TINY_BLOCKS			64520
-#define SHIFT_TINY_CEIL_BLOCKS		16 // ceil(log2(NUM_TINY_BLOCKS))
-#define NUM_TINY_CEIL_BLOCKS		(1 << SHIFT_TINY_CEIL_BLOCKS)
-#define TINY_BLOCKS_ALIGN		(SHIFT_TINY_CEIL_BLOCKS + SHIFT_TINY_QUANTUM) // 20
-
-#define TINY_ENTROPY_BITS		15
-#define TINY_ENTROPY_MASK		((1 << TINY_ENTROPY_BITS) - 1)
-
-/*
- * Avoid having so much entropy that the end of a valid tiny allocation
- * might overrun the end of the tiny region.
- */
-#if TINY_ENTROPY_MASK + NUM_TINY_SLOTS > NUM_TINY_BLOCKS
-#error Too many entropy bits for tiny region requested
-#endif
-
-/*
- * Enough room for the data, followed by the bit arrays (2-bits per block)
- * plus rounding to the nearest page.
- */
-#define CEIL_NUM_TINY_BLOCKS_WORDS	(((NUM_TINY_BLOCKS + 31) & ~31) >> 5)
-#define TINY_METADATA_SIZE		(sizeof(region_trailer_t) + sizeof(tiny_header_inuse_pair_t) * CEIL_NUM_TINY_BLOCKS_WORDS)
-#define TINY_REGION_SIZE							\
-	((NUM_TINY_BLOCKS * TINY_QUANTUM + TINY_METADATA_SIZE + PAGE_MAX_SIZE - 1) & ~ (PAGE_MAX_SIZE - 1))
-
-#define TINY_METADATA_START		(NUM_TINY_BLOCKS * TINY_QUANTUM)
-
-/*
- * Beginning and end pointers for a region's heap.
- */
-#define TINY_REGION_ADDRESS(region)	((void *)(region))
-#define TINY_REGION_END(region)		((void *)(((uintptr_t)(region)) + (NUM_TINY_BLOCKS * TINY_QUANTUM)))
-
-/*
- * Locate the heap base for a pointer known to be within a tiny region.
- */
-#define TINY_REGION_FOR_PTR(_p)		((void *)((uintptr_t)(_p) & ~((1 << TINY_BLOCKS_ALIGN) - 1)))
-
-/*
- * Convert between byte and msize units.
- */
-#define TINY_BYTES_FOR_MSIZE(_m)	((_m) << SHIFT_TINY_QUANTUM)
-#define TINY_MSIZE_FOR_BYTES(_b)	((_b) >> SHIFT_TINY_QUANTUM)
-
-#ifdef __LP64__
-# define TINY_FREE_SIZE(ptr)		(((msize_t *)(ptr))[8])
-#else
-# define TINY_FREE_SIZE(ptr)		(((msize_t *)(ptr))[4])
-#endif
-#define TINY_PREVIOUS_MSIZE(ptr)	((msize_t *)(ptr))[-1]
-
-/*
- * Layout of a tiny region
- */
-typedef uint32_t tiny_block_t[4]; // assert(TINY_QUANTUM == sizeof(tiny_block_t))
-
-typedef struct tiny_header_inuse_pair
-{
-	uint32_t	header;
-	uint32_t	inuse;
-} tiny_header_inuse_pair_t;
-
-typedef struct region_trailer
-{
-	struct region_trailer	*prev;
-	struct region_trailer	*next;
-	boolean_t			recirc_suitable;
-	volatile int		pinned_to_depot;
-	unsigned			bytes_used;
-	mag_index_t			mag_index;
-} region_trailer_t;
-
-typedef struct tiny_region
-{
-	tiny_block_t blocks[NUM_TINY_BLOCKS];
-
-	region_trailer_t trailer;
-
-	// The interleaved bit arrays comprising the header and inuse bitfields.
-	// The unused bits of each component in the last pair will be initialized to sentinel values.
-	tiny_header_inuse_pair_t pairs[CEIL_NUM_TINY_BLOCKS_WORDS];
-
-	uint8_t pad[TINY_REGION_SIZE - (NUM_TINY_BLOCKS * sizeof(tiny_block_t)) - TINY_METADATA_SIZE];
-} *tiny_region_t;
-
-/*
- * Per-region meta data for tiny allocator
- */
-#define REGION_TRAILER_FOR_TINY_REGION(r)	(&(((tiny_region_t)(r))->trailer))
-#define MAGAZINE_INDEX_FOR_TINY_REGION(r)	(REGION_TRAILER_FOR_TINY_REGION(r)->mag_index)
-#define BYTES_USED_FOR_TINY_REGION(r)		(REGION_TRAILER_FOR_TINY_REGION(r)->bytes_used)
-
-/*
- * Locate the block header for a pointer known to be within a tiny region.
- */
-#define TINY_BLOCK_HEADER_FOR_PTR(_p)	((void *)&(((tiny_region_t)TINY_REGION_FOR_PTR(_p))->pairs))
-
-/*
- * Locate the inuse map for a given block header pointer.
- */
-#define TINY_INUSE_FOR_HEADER(_h)	((void *)&(((tiny_header_inuse_pair_t *)(_h))->inuse))
-
-/*
- * Compute the bitmap index for a pointer known to be within a tiny region.
- */
-#define TINY_INDEX_FOR_PTR(_p) 		(((uintptr_t)(_p) >> SHIFT_TINY_QUANTUM) & (NUM_TINY_CEIL_BLOCKS - 1))
-
-#define TINY_CACHE			1	// This governs a last-free cache of 1 that bypasses the free-list
-
-#if ! TINY_CACHE
-#warning TINY_CACHE turned off
-#endif
-
-#define TINY_REGION_PAYLOAD_BYTES	(NUM_TINY_BLOCKS * TINY_QUANTUM)
-
-/*********************	DEFINITIONS for small	************************/
-
-/*
- * Memory in the Small range is allocated from regions (heaps) pointed to by the szone's hashed_regions
- * pointer.
- *
- * Each region is laid out as a heap, followed by the metadata array, all within an 8MB (2^23) block.
- * The array is arranged as an array of shorts, one for each SMALL_QUANTUM in the heap.
- * This means there are 16320 512-blocks and the array is 16320*2 bytes, which totals 8388480, leaving
- * 128 bytes unused.
- *
- * The MSB of each short is set for the first quantum in a free block.  The low 15 bits encode the
- * block size (in SMALL_QUANTUM units), or are zero if the quantum is not the first in a block.
- *
- * The szone maintains an array of 32 freelists, each of which is used to hold free objects
- * of the corresponding quantum size.
- *
- * A free block is laid out as:
- *
- * Offset (32-bit mode)	(64-bit mode)
- * 0x0          0x0      : previous
- * 0x4          0x08     : next
- * 0x8          0x10     : size (in quantum counts)
- * end - 2	end - 2  : size (in quantum counts)
- * end		end
- *
- * All fields are pointer-sized, except for the size which is an unsigned short.
- *
- */
-
-#define SMALL_IS_FREE			(1 << 15)
-
-#define	SHIFT_SMALL_QUANTUM		(SHIFT_TINY_QUANTUM + 5)	// 9
-#define	SMALL_QUANTUM			(1 << SHIFT_SMALL_QUANTUM)	// 512 bytes
-
-#define FOLLOWING_SMALL_PTR(ptr,msize)	(((unsigned char *)(ptr)) + ((msize) << SHIFT_SMALL_QUANTUM))
-
-/*
- * The number of slots in the free-list for small blocks.  To avoid going to
- * vm system as often on large memory machines, increase the number of free list
- * spots above some amount of RAM installed in the system.
- */
-#define NUM_SMALL_SLOTS			32
-#define NUM_SMALL_SLOTS_LARGEMEM	256
-#define SMALL_BITMAP_WORDS		8
-
-/*
- * We can only represent up to 1<<15 for msize; but we choose to stay even below that to avoid the
- * convention msize=0 => msize = (1<<15)
- */
-#define NUM_SMALL_BLOCKS		16320
-#define SHIFT_SMALL_CEIL_BLOCKS		14 // ceil(log2(NUM_SMALL_BLOCKs))
-#define NUM_SMALL_CEIL_BLOCKS		(1 << SHIFT_SMALL_CEIL_BLOCKS)
-#define SMALL_BLOCKS_ALIGN		(SHIFT_SMALL_CEIL_BLOCKS + SHIFT_SMALL_QUANTUM) // 23
-
-#define SMALL_ENTROPY_BITS		13
-#define SMALL_ENTROPY_MASK		((1 << SMALL_ENTROPY_BITS) - 1)
-
-/*
- * Avoid having so much entropy that the end of a valid small allocation
- * might overrun the end of the small region.
- */
-#if SMALL_ENTROPY_MASK + NUM_SMALL_SLOTS > NUM_SMALL_BLOCKS
-#error Too many entropy bits for small region requested
-#endif
-
-#define SMALL_METADATA_SIZE		(sizeof(region_trailer_t) + NUM_SMALL_BLOCKS * sizeof(msize_t))
-#define SMALL_REGION_SIZE						\
-	((NUM_SMALL_BLOCKS * SMALL_QUANTUM + SMALL_METADATA_SIZE + PAGE_MAX_SIZE - 1) & ~ (PAGE_MAX_SIZE - 1))
-
-#define SMALL_METADATA_START		(NUM_SMALL_BLOCKS * SMALL_QUANTUM)
-
-/*
- * Beginning and end pointers for a region's heap.
- */
-#define SMALL_REGION_ADDRESS(region)	((unsigned char *)region)
-#define SMALL_REGION_END(region)	(SMALL_REGION_ADDRESS(region) + (NUM_SMALL_BLOCKS * SMALL_QUANTUM))
-
-/*
- * Locate the heap base for a pointer known to be within a small region.
- */
-#define SMALL_REGION_FOR_PTR(_p)	((void *)((uintptr_t)(_p) & ~((1 << SMALL_BLOCKS_ALIGN) - 1)))
-
-/*
- * Convert between byte and msize units.
- */
-#define SMALL_BYTES_FOR_MSIZE(_m)	((_m) << SHIFT_SMALL_QUANTUM)
-#define SMALL_MSIZE_FOR_BYTES(_b)	((_b) >> SHIFT_SMALL_QUANTUM)
-
-#define SMALL_PREVIOUS_MSIZE(ptr)	((msize_t *)(ptr))[-1]
-
-/*
- * Layout of a small region
- */
-typedef uint32_t small_block_t[SMALL_QUANTUM/sizeof(uint32_t)];
-
-typedef struct small_region
-{
-	small_block_t blocks[NUM_SMALL_BLOCKS];
-
-	region_trailer_t trailer;
-
-	msize_t small_meta_words[NUM_SMALL_BLOCKS];
-
-	uint8_t pad[SMALL_REGION_SIZE - (NUM_SMALL_BLOCKS * sizeof(small_block_t)) - SMALL_METADATA_SIZE];
-} *small_region_t;
-
-/*
- * Per-region meta data for small allocator
- */
-#define REGION_TRAILER_FOR_SMALL_REGION(r)	(&(((small_region_t)(r))->trailer))
-#define MAGAZINE_INDEX_FOR_SMALL_REGION(r)	(REGION_TRAILER_FOR_SMALL_REGION(r)->mag_index)
-#define BYTES_USED_FOR_SMALL_REGION(r)		(REGION_TRAILER_FOR_SMALL_REGION(r)->bytes_used)
-
-/*
- * Locate the metadata base for a pointer known to be within a small region.
- */
-#define SMALL_META_HEADER_FOR_PTR(_p)	(((small_region_t)SMALL_REGION_FOR_PTR(_p))->small_meta_words)
-
-/*
- * Compute the metadata index for a pointer known to be within a small region.
- */
-#define SMALL_META_INDEX_FOR_PTR(_p)	(((uintptr_t)(_p) >> SHIFT_SMALL_QUANTUM) & (NUM_SMALL_CEIL_BLOCKS - 1))
-
-/*
- * Find the metadata word for a pointer known to be within a small region.
- */
-#define SMALL_METADATA_FOR_PTR(_p)	(SMALL_META_HEADER_FOR_PTR(_p) + SMALL_META_INDEX_FOR_PTR(_p))
-
-/*
- * Determine whether a pointer known to be within a small region points to memory which is free.
- */
-#define SMALL_PTR_IS_FREE(_p)		(*SMALL_METADATA_FOR_PTR(_p) & SMALL_IS_FREE)
-
-/*
- * Extract the msize value for a pointer known to be within a small region.
- */
-#define SMALL_PTR_SIZE(_p)		(*SMALL_METADATA_FOR_PTR(_p) & ~SMALL_IS_FREE)
-
-#define SMALL_CACHE			1
-#if !SMALL_CACHE
-#warning SMALL_CACHE turned off
-#endif
-
-#define SMALL_REGION_PAYLOAD_BYTES	(NUM_SMALL_BLOCKS * SMALL_QUANTUM)
-
-/*************************  DEFINITIONS for large  ****************************/
-
-#define LARGE_THRESHOLD			(15 * 1024) // strictly above this use "large"
-#define LARGE_THRESHOLD_LARGEMEM	(127 * 1024)
-
-#if (LARGE_THRESHOLD > NUM_SMALL_SLOTS * SMALL_QUANTUM)
-#error LARGE_THRESHOLD should always be less than NUM_SMALL_SLOTS * SMALL_QUANTUM
-#endif
-
-#if (LARGE_THRESHOLD_LARGEMEM > NUM_SMALL_SLOTS_LARGEMEM * SMALL_QUANTUM)
-#error LARGE_THRESHOLD_LARGEMEM should always be less than NUM_SMALL_SLOTS * SMALL_QUANTUM
-#endif
-
-/*
- * When all memory is touched after a copy, vm_copy() is always a lose
- * But if the memory is only read, vm_copy() wins over memmove() at 3 or 4 pages
- * (on a G3/300MHz)
- *
- * This must be larger than LARGE_THRESHOLD
- */
-#define VM_COPY_THRESHOLD		(40 * 1024)
-#define VM_COPY_THRESHOLD_LARGEMEM	(128 * 1024)
-
-typedef struct {
-	vm_address_t address;
-	vm_size_t size;
-	boolean_t did_madvise_reusable;
-} large_entry_t;
-
-#if !TARGET_OS_EMBEDDED
-#define LARGE_CACHE			1
-#else
-#define LARGE_CACHE			0
-#endif
-#if !LARGE_CACHE
-#warning LARGE_CACHE turned off
-#endif
-#if defined(__LP64__)
-#define LARGE_ENTRY_CACHE_SIZE 16
-#define LARGE_CACHE_SIZE_LIMIT ((vm_size_t)0x80000000) /* 2Gb */
-#else
-#define LARGE_ENTRY_CACHE_SIZE 8
-#define LARGE_CACHE_SIZE_LIMIT ((vm_size_t)0x02000000) /* 32Mb */
-#endif
-#define LARGE_CACHE_SIZE_ENTRY_LIMIT (LARGE_CACHE_SIZE_LIMIT/LARGE_ENTRY_CACHE_SIZE)
-
-#define SZONE_FLOTSAM_THRESHOLD_LOW  (1024 * 512)
-#define SZONE_FLOTSAM_THRESHOLD_HIGH (1024 * 1024)
-
-/*******************************************************************************
- * Definitions for region hash
- ******************************************************************************/
-
-typedef void * region_t;
-typedef region_t * rgnhdl_t; /* A pointer into hashed_regions array. */
-
-#define INITIAL_NUM_REGIONS_SHIFT	6 // log2(INITIAL_NUM_REGIONS)
-#define INITIAL_NUM_REGIONS		(1 << INITIAL_NUM_REGIONS_SHIFT) // Must be a power of 2!
-#define HASHRING_OPEN_ENTRY		((region_t) 0) // Initial value and sentinel marking end of collision chain
-#define HASHRING_REGION_DEALLOCATED	((region_t)-1) // Region at this slot reclaimed by OS
-#define HASH_BLOCKS_ALIGN		TINY_BLOCKS_ALIGN // MIN( TINY_BLOCKS_ALIGN, SMALL_BLOCKS_ALIGN, ... )
-
-typedef struct region_hash_generation {
-	size_t		num_regions_allocated;
-	size_t		num_regions_allocated_shift; // log2(num_regions_allocated)
-	region_t		*hashed_regions;  // hashed by location
-	struct		region_hash_generation *nextgen;
-} region_hash_generation_t;
-
-/*******************************************************************************
- * Per-processor magazine for tiny and small allocators
- ******************************************************************************/
-
-typedef struct {			// vm_allocate()'d, so the array of magazines is page-aligned to begin with.
-	// Take magazine_lock first,  Depot lock when needed for recirc, then szone->{tiny,small}_regions_lock when needed for alloc
-	_malloc_lock_s		magazine_lock CACHE_ALIGN;
-	// Protection for the crtical section that does allocate_pages outside the magazine_lock
-	volatile boolean_t	alloc_underway;
-
-	// One element deep "death row", optimizes malloc/free/malloc for identical size.
-	void		*mag_last_free; // low SHIFT_{TINY,SMALL}_QUANTUM bits indicate the msize
-	region_t		mag_last_free_rgn; // holds the region for mag_last_free
-
-	free_list_t		*mag_free_list[256]; // assert( 256 >= MAX( NUM_TINY_SLOTS, NUM_SMALL_SLOTS_LARGEMEM ))
-	unsigned		mag_bitmap[8]; // assert( sizeof(mag_bitmap) << 3 >= sizeof(mag_free_list)/sizeof(free_list_t) )
-
-	// the first and last free region in the last block are treated as big blocks in use that are not accounted for
-	size_t		mag_bytes_free_at_end;
-	size_t		mag_bytes_free_at_start;
-	region_t		mag_last_region; // Valid iff mag_bytes_free_at_end || mag_bytes_free_at_start > 0
-
-	// bean counting ...
-	unsigned		mag_num_objects;
-	size_t		mag_num_bytes_in_objects;
-	size_t		num_bytes_in_magazine;
-
-	// recirculation list -- invariant: all regions owned by this magazine that meet the emptiness criteria
-	// are located nearer to the head of the list than any region that doesn't satisfy that criteria.
-	// Doubly linked list for efficient extraction.
-	unsigned		recirculation_entries;
-	region_trailer_t	*firstNode;
-	region_trailer_t	*lastNode;
-
-	uintptr_t		pad[50-CACHE_LINE/sizeof(uintptr_t)];
-} magazine_t;
-
-#ifdef __has_extension
-#if __has_extension(c_static_assert)
-#if __LP64__
-_Static_assert(sizeof(magazine_t) == 2560, "Incorrect padding in magazine_t");
-#else
-_Static_assert(sizeof(magazine_t) == 1280, "Incorrect padding in magazine_t");
-#endif
-#endif
-#endif
-
-#define TINY_MAX_MAGAZINES		32 /* MUST BE A POWER OF 2! */
-#define TINY_MAGAZINE_PAGED_SIZE						\
-(((sizeof(magazine_t) * (TINY_MAX_MAGAZINES + 1)) + vm_page_quanta_size - 1) &\
-~ (vm_page_quanta_size - 1)) /* + 1 for the Depot */
-
-#define SMALL_MAX_MAGAZINES		32 /* MUST BE A POWER OF 2! */
-#define SMALL_MAGAZINE_PAGED_SIZE						\
-(((sizeof(magazine_t) * (SMALL_MAX_MAGAZINES + 1)) + vm_page_quanta_size - 1) &\
-~ (vm_page_quanta_size - 1)) /* + 1 for the Depot */
-
-#define DEPOT_MAGAZINE_INDEX		-1
-
-/****************************** zone itself ***********************************/
-
-/*
- * Note that objects whose adddress are held in pointers here must be pursued
- * individually in the {tiny,small}_in_use_enumeration() routines. See for
- * example the treatment of region_hash_generation and tiny_magazines below.
- */
-
-typedef struct szone_s {				// vm_allocate()'d, so page-aligned to begin with.
-	malloc_zone_t		basic_zone;		// first page will be given read-only protection
-	uint8_t			pad[PAGE_MAX_SIZE - sizeof(malloc_zone_t)];
-
-	unsigned long		cpu_id_key;		// unused
-	// remainder of structure is R/W (contains no function pointers)
-	unsigned			debug_flags;
-	void			*log_address;
-
-	/* Regions for tiny objects */
-	_malloc_lock_s	tiny_regions_lock CACHE_ALIGN;
-	size_t			num_tiny_regions;
-	size_t			num_tiny_regions_dealloc;
-	region_hash_generation_t	*tiny_region_generation;
-	region_hash_generation_t	trg[2];
-
-	int				num_tiny_magazines;
-	unsigned			num_tiny_magazines_mask;
-	int				num_tiny_magazines_mask_shift;
-	magazine_t			*tiny_magazines; // array of per-processor magazines
-
-	uintptr_t			last_tiny_advise;
-
-	/* Regions for small objects */
-	_malloc_lock_s	small_regions_lock CACHE_ALIGN;
-	size_t			num_small_regions;
-	size_t			num_small_regions_dealloc;
-	region_hash_generation_t	*small_region_generation;
-	region_hash_generation_t	srg[2];
-
-	unsigned			num_small_slots; // determined by physmem size
-
-	int				num_small_magazines;
-	unsigned			num_small_magazines_mask;
-	int				num_small_magazines_mask_shift;
-	magazine_t			*small_magazines; // array of per-processor magazines
-
-	uintptr_t			last_small_advise;
-
-	/* large objects: all the rest */
-	_malloc_lock_s		large_szone_lock CACHE_ALIGN; // One customer at a time for large
-	unsigned			num_large_objects_in_use;
-	unsigned			num_large_entries;
-	large_entry_t		*large_entries; // hashed by location; null entries don't count
-	size_t			num_bytes_in_large_objects;
-
-#if LARGE_CACHE
-	int				large_entry_cache_oldest;
-	int				large_entry_cache_newest;
-	large_entry_t		large_entry_cache[LARGE_ENTRY_CACHE_SIZE]; // "death row" for large malloc/free
-	boolean_t			large_legacy_reset_mprotect;
-	size_t			large_entry_cache_reserve_bytes;
-	size_t			large_entry_cache_reserve_limit;
-	size_t			large_entry_cache_bytes; // total size of death row, bytes
-#endif
-
-	/* flag and limits pertaining to altered malloc behavior for systems with
-	 large amounts of physical memory */
-	unsigned  is_largemem;
-	unsigned  large_threshold;
-	unsigned  vm_copy_threshold;
-
-	/* security cookie */
-	uintptr_t cookie;
-
-	/* Initial region list */
-	region_t			initial_tiny_regions[INITIAL_NUM_REGIONS];
-	region_t			initial_small_regions[INITIAL_NUM_REGIONS];
-
-	/* The purgeable zone constructed by create_purgeable_zone() would like to hand off tiny and small
-	 * allocations to the default scalable zone. Record the latter as the "helper" zone here. */
-	struct szone_s		*helper_zone;
-
-	boolean_t			flotsam_enabled;
-} szone_t;
-
-#define SZONE_PAGED_SIZE		round_page_quanta((sizeof(szone_t)))
-
-#if DEBUG_MALLOC || DEBUG_CLIENT
-static void		szone_sleep(void);
-#endif
-extern void malloc_error_break(void);
-
-// msg prints after fmt, ...
-static NOINLINE void	szone_error(szone_t *szone, int is_corruption, const char *msg, const void *ptr, const char *fmt, ...)
-__printflike(5, 6);
-
-static void		protect(void *address, size_t size, unsigned protection, unsigned debug_flags);
-static void		*allocate_pages(szone_t *szone, size_t size, unsigned char align, unsigned debug_flags,
-								int vm_page_label);
-static void		*allocate_pages_securely(szone_t *szone, size_t size, unsigned char align,
-										 int vm_page_label);
-static void		deallocate_pages(szone_t *szone, void *addr, size_t size, unsigned debug_flags);
-static int		madvise_free_range(szone_t *szone, region_t r, uintptr_t pgLo, uintptr_t pgHi, uintptr_t *last);
-static kern_return_t	_szone_default_reader(task_t task, vm_address_t address, vm_size_t size, void **ptr);
-
-static INLINE		mag_index_t mag_get_thread_index(szone_t *szone) ALWAYSINLINE;
-static magazine_t	*mag_lock_zine_for_region_trailer(szone_t *szone, magazine_t *magazines, region_trailer_t *trailer,
-													  mag_index_t mag_index);
-
-static INLINE rgnhdl_t	hash_lookup_region_no_lock(region_t *regions, size_t num_entries, size_t shift, region_t r)
-ALWAYSINLINE;
-static void		hash_region_insert_no_lock(region_t *regions, size_t num_entries, size_t shift, region_t r);
-static region_t		*hash_regions_alloc_no_lock(szone_t *szone, size_t num_entries);
-static region_t		*hash_regions_grow_no_lock(szone_t *szone, region_t *regions, size_t old_size,
-											   size_t *mutable_shift, size_t *new_size);
-
-static INLINE uintptr_t free_list_gen_checksum(uintptr_t ptr) ALWAYSINLINE;
-static INLINE uintptr_t free_list_checksum_ptr(szone_t *szone, void *p) ALWAYSINLINE;
-static INLINE void	*free_list_unchecksum_ptr(szone_t *szone, ptr_union *ptr) ALWAYSINLINE;
-static unsigned		free_list_count(szone_t *szone, free_list_t *ptr);
-
-static INLINE void	recirc_list_extract(szone_t *szone, magazine_t *mag_ptr, region_trailer_t *node) ALWAYSINLINE;
-static INLINE void	recirc_list_splice_last(szone_t *szone, magazine_t *mag_ptr, region_trailer_t *node) ALWAYSINLINE;
-static INLINE void	recirc_list_splice_first(szone_t *szone, magazine_t *mag_ptr, region_trailer_t *node) ALWAYSINLINE;
-
-static INLINE void	BITARRAY_SET(uint32_t *bits, msize_t index) ALWAYSINLINE;
-static INLINE void	BITARRAY_CLR(uint32_t *bits, msize_t index) ALWAYSINLINE;
-static INLINE boolean_t BITARRAY_BIT(uint32_t *bits, msize_t index) ALWAYSINLINE;
-
-static msize_t		get_tiny_free_size(const void *ptr);
-static msize_t		get_tiny_previous_free_msize(const void *ptr);
-static INLINE msize_t	get_tiny_meta_header(const void *ptr, boolean_t *is_free) ALWAYSINLINE;
-static INLINE void	set_tiny_meta_header_in_use(const void *ptr, msize_t msize) ALWAYSINLINE;
-static INLINE void	set_tiny_meta_header_in_use_1(const void *ptr) ALWAYSINLINE;
-static INLINE void	set_tiny_meta_header_middle(const void *ptr) ALWAYSINLINE;
-static INLINE void	set_tiny_meta_header_free(const void *ptr, msize_t msize) ALWAYSINLINE;
-static INLINE boolean_t	tiny_meta_header_is_free(const void *ptr) ALWAYSINLINE;
-static INLINE void	*tiny_previous_preceding_free(void *ptr, msize_t *prev_msize) ALWAYSINLINE;
-
-static void		tiny_free_list_add_ptr(szone_t *szone, magazine_t *tiny_mag_ptr, void *ptr, msize_t msize);
-static void		tiny_free_list_remove_ptr(szone_t *szone, magazine_t *tiny_mag_ptr, void *ptr, msize_t msize);
-static INLINE region_t	tiny_region_for_ptr_no_lock(szone_t *szone, const void *ptr) ALWAYSINLINE;
-
-static void		tiny_finalize_region(szone_t *szone, magazine_t *tiny_mag_ptr);
-static int		tiny_free_detach_region(szone_t *szone, magazine_t *tiny_mag_ptr, region_t r);
-static size_t		tiny_free_reattach_region(szone_t *szone, magazine_t *tiny_mag_ptr, region_t r);
-static void		tiny_free_scan_madvise_free(szone_t *szone, magazine_t *depot_ptr, region_t r);
-static region_t		tiny_free_try_depot_unmap_no_lock(szone_t *szone, magazine_t *depot_ptr, region_trailer_t *node);
-static boolean_t	tiny_free_do_recirc_to_depot(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index);
-static region_t		tiny_find_msize_region(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize);
-static boolean_t	tiny_get_region_from_depot(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize);
-
-static INLINE boolean_t	tiny_free_no_lock(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, region_t region,
-										  void *ptr, msize_t msize) ALWAYSINLINE;
-static void		*tiny_malloc_from_region_no_lock(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index,
-												 msize_t msize, void *fresh_region);
-static boolean_t	tiny_try_realloc_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_size);
-static boolean_t	tiny_check_region(szone_t *szone, region_t region);
-static kern_return_t	tiny_in_use_enumerator(task_t task, void *context, unsigned type_mask, szone_t *szone,
-											   memory_reader_t reader, vm_range_recorder_t recorder);
-static void		*tiny_malloc_from_free_list(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index,
-											msize_t msize);
-static INLINE void	*tiny_malloc_should_clear(szone_t *szone, msize_t msize, boolean_t cleared_requested) ALWAYSINLINE;
-static INLINE void	free_tiny(szone_t *szone, void *ptr, region_t tiny_region, size_t known_size) ALWAYSINLINE;
-static void		print_tiny_free_list(szone_t *szone);
-static void		print_tiny_region(boolean_t verbose, region_t region, size_t bytes_at_start, size_t bytes_at_end);
-static boolean_t	tiny_free_list_check(szone_t *szone, grain_t slot);
-
-static INLINE void	small_meta_header_set_is_free(msize_t *meta_headers, unsigned index, msize_t msize) ALWAYSINLINE;
-static INLINE void	small_meta_header_set_in_use(msize_t *meta_headers, msize_t index, msize_t msize) ALWAYSINLINE;
-static INLINE void	small_meta_header_set_middle(msize_t *meta_headers, msize_t index) ALWAYSINLINE;
-static void		small_free_list_add_ptr(szone_t *szone, magazine_t *small_mag_ptr, void *ptr, msize_t msize);
-static void		small_free_list_remove_ptr(szone_t *szone, magazine_t *small_mag_ptr, void *ptr, msize_t msize);
-static INLINE region_t	small_region_for_ptr_no_lock(szone_t *szone, const void *ptr) ALWAYSINLINE;
-
-static void		small_finalize_region(szone_t *szone, magazine_t *small_mag_ptr);
-static int		small_free_detach_region(szone_t *szone, magazine_t *small_mag_ptr, region_t r);
-static size_t		small_free_reattach_region(szone_t *szone, magazine_t *small_mag_ptr, region_t r);
-static void		small_free_scan_madvise_free(szone_t *szone, magazine_t *depot_ptr, region_t r);
-static region_t		small_free_try_depot_unmap_no_lock(szone_t *szone, magazine_t *depot_ptr, region_trailer_t *node);
-static boolean_t	small_free_do_recirc_to_depot(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index);
-static region_t		small_find_msize_region(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize);
-static boolean_t	small_get_region_from_depot(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize);
-static INLINE boolean_t	small_free_no_lock(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, region_t region,
-										   void *ptr, msize_t msize) ALWAYSINLINE;
-static void		*small_malloc_from_region_no_lock(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index,
-												  msize_t msize, void *fresh_region);
-static boolean_t	small_try_realloc_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_size);
-static boolean_t	small_check_region(szone_t *szone, region_t region);
-static kern_return_t	small_in_use_enumerator(task_t task, void *context, unsigned type_mask, szone_t *szone,
-												memory_reader_t reader, vm_range_recorder_t recorder);
-static void		*small_malloc_from_free_list(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index,
-											 msize_t msize);
-static INLINE void	*small_malloc_should_clear(szone_t *szone, msize_t msize, boolean_t cleared_requested) ALWAYSINLINE;
-static INLINE void	free_small(szone_t *szone, void *ptr, region_t small_region, size_t known_size) ALWAYSINLINE;
-static void		print_small_free_list(szone_t *szone);
-static void		print_small_region(szone_t *szone, boolean_t verbose, region_t region, size_t bytes_at_start, size_t bytes_at_end);
-static boolean_t	small_free_list_check(szone_t *szone, grain_t grain);
-
-#if DEBUG_MALLOC
-static void		large_debug_print(szone_t *szone);
-#endif
-static large_entry_t	*large_entry_for_pointer_no_lock(szone_t *szone, const void *ptr);
-static void		large_entry_insert_no_lock(szone_t *szone, large_entry_t range);
-static INLINE void	large_entries_rehash_after_entry_no_lock(szone_t *szone, large_entry_t *entry) ALWAYSINLINE;
-static INLINE large_entry_t *large_entries_alloc_no_lock(szone_t *szone, unsigned num) ALWAYSINLINE;
-static void		large_entries_free_no_lock(szone_t *szone, large_entry_t *entries, unsigned num,
-										   vm_range_t *range_to_deallocate);
-static large_entry_t	*large_entries_grow_no_lock(szone_t *szone, vm_range_t *range_to_deallocate);
-static vm_range_t	large_entry_free_no_lock(szone_t *szone, large_entry_t *entry);
-static NOINLINE		kern_return_t	large_in_use_enumerator(task_t task, void *context,
-															unsigned type_mask, vm_address_t large_entries_address,
-															unsigned num_entries, memory_reader_t reader,
-															vm_range_recorder_t recorder);
-static void		*large_malloc(szone_t *szone, size_t num_kernel_pages, unsigned char alignment, boolean_t cleared_requested);
-static NOINLINE void	free_large(szone_t *szone, void *ptr);
-static INLINE int	large_try_realloc_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_size) ALWAYSINLINE;
-
-/*
- * Mark these NOINLINE to avoid bloating the purgeable zone call backs
- */
-static NOINLINE void	szone_free(szone_t *szone, void *ptr);
-static NOINLINE void	*szone_malloc_should_clear(szone_t *szone, size_t size, boolean_t cleared_requested);
-static NOINLINE void	*szone_malloc(szone_t *szone, size_t size);
-static NOINLINE void	*szone_calloc(szone_t *szone, size_t num_items, size_t size);
-static NOINLINE void	*szone_valloc(szone_t *szone, size_t size);
-static NOINLINE size_t	szone_size_try_large(szone_t *szone, const void *ptr);
-static NOINLINE size_t	szone_size(szone_t *szone, const void *ptr);
-static NOINLINE void	*szone_realloc(szone_t *szone, void *ptr, size_t new_size);
-static NOINLINE void	*szone_memalign(szone_t *szone, size_t alignment, size_t size);
-static NOINLINE void	szone_free_definite_size(szone_t *szone, void *ptr, size_t size);
-static NOINLINE unsigned szone_batch_malloc(szone_t *szone, size_t size, void **results, unsigned count);
-static NOINLINE void	szone_batch_free(szone_t *szone, void **to_be_freed, unsigned count);
-static void		szone_destroy(szone_t *szone);
-static NOINLINE size_t	szone_good_size(szone_t *szone, size_t size);
-
-static NOINLINE boolean_t szone_check_all(szone_t *szone, const char *function);
-static boolean_t	szone_check(szone_t *szone);
-static kern_return_t	szone_ptr_in_use_enumerator(task_t task, void *context,
-													unsigned type_mask, vm_address_t zone_address,
-													memory_reader_t reader, vm_range_recorder_t recorder);
-static NOINLINE void	szone_print(szone_t *szone, boolean_t verbose);
-static void		szone_log(malloc_zone_t *zone, void *log_address);
-static void		szone_force_lock(szone_t *szone);
-static INLINE void	szone_force_lock_magazine(szone_t *szone, magazine_t *mag);
-static void		szone_force_unlock(szone_t *szone);
-static boolean_t	szone_locked(szone_t *szone);
-
-static void		szone_statistics(szone_t *szone, malloc_statistics_t *stats);
-
-static void		purgeable_free(szone_t *szone, void *ptr);
-static void		*purgeable_malloc(szone_t *szone, size_t size);
-static void		*purgeable_calloc(szone_t *szone, size_t num_items, size_t size);
-static void		*purgeable_valloc(szone_t *szone, size_t size);
-static size_t		purgeable_size(szone_t *szone, const void *ptr);
-static void		*purgeable_realloc(szone_t *szone, void *ptr, size_t new_size);
-static void		*purgeable_memalign(szone_t *szone, size_t alignment, size_t size);
-static void		purgeable_free_definite_size(szone_t *szone, void *ptr, size_t size);
-static unsigned		purgeable_batch_malloc(szone_t *szone, size_t size, void **results, unsigned count);
-static void		purgeable_batch_free(szone_t *szone, void **to_be_freed, unsigned count);
-static void		purgeable_destroy(szone_t *szone);
-static size_t		purgeable_good_size(szone_t *szone, size_t size);
-
-static boolean_t	purgeable_check(szone_t *szone);
-static kern_return_t	purgeable_ptr_in_use_enumerator(task_t task, void *context,
-														unsigned type_mask, vm_address_t zone_address,
-														memory_reader_t reader, vm_range_recorder_t recorder);
-static void		purgeable_print(szone_t *szone, boolean_t verbose);
-static void		purgeable_log(malloc_zone_t *zone, void *log_address);
-static void		purgeable_force_lock(szone_t *szone);
-static void		purgeable_force_unlock(szone_t *szone);
-static boolean_t	purgeable_locked(szone_t *szone);
-
-static void		purgeable_statistics(szone_t *szone, malloc_statistics_t *stats);
-
-static void		*frozen_malloc(szone_t *zone, size_t new_size);
-static void		*frozen_calloc(szone_t *zone, size_t num_items, size_t size);
-static void		*frozen_valloc(szone_t *zone, size_t new_size);
-static void		*frozen_realloc(szone_t *zone, void *ptr, size_t new_size);
-static void		frozen_free(szone_t *zone, void *ptr);
-static void		frozen_destroy(szone_t *zone);
-
-static volatile uintptr_t entropic_address = 0;
-static volatile uintptr_t entropic_limit = 0;
-#define ENTROPIC_KABILLION 0x10000000 /* 256Mb */
-
-extern uint64_t malloc_entropy[2];
-
-static inline void
-SZONE_LOCK(szone_t *szone) {
-	_malloc_lock_lock(&szone->large_szone_lock);
-}
-
-static inline void
-SZONE_UNLOCK(szone_t *szone) {
-	_malloc_lock_unlock(&szone->large_szone_lock);
-}
-
-static inline bool
-SZONE_TRY_LOCK(szone_t *szone) {
-	return _malloc_lock_trylock(&szone->large_szone_lock);
-}
-
-static inline void
-SZONE_MAGAZINE_PTR_LOCK(szone_t *szone, magazine_t *mag_ptr) {
-	_malloc_lock_lock(&mag_ptr->magazine_lock);
-}
-
-static inline void
-SZONE_MAGAZINE_PTR_UNLOCK(szone_t *szone, magazine_t *mag_ptr) {
-	_malloc_lock_unlock(&mag_ptr->magazine_lock);
-}
-
-static inline bool
-SZONE_MAGAZINE_PTR_TRY_LOCK(szone_t *szone, magazine_t *mag_ptr) {
-	return _malloc_lock_trylock(&mag_ptr->magazine_lock);
-}
-
-static inline void yield(void) {
-	thread_switch(MACH_PORT_NULL, SWITCH_OPTION_DEPRESS, 1);
-}
-
-#if DEBUG_MALLOC
-# define LOG(szone,ptr)							\
-	(szone->log_address && (((uintptr_t)szone->log_address == -1) ||	\
-	(szone->log_address == (void *)(ptr))))
-#else
-# define LOG(szone,ptr)		0
-#endif
-
-#if DEBUG_MALLOC || DEBUG_CLIENT
-# define CHECK(szone,fun)						\
-	if ((szone)->debug_flags & CHECK_REGIONS)				\
-	szone_check_all(szone, fun)
-#else
-# define CHECK(szone,fun)						\
-	do {} while (0)
-#endif
-
-/*********************	VERY LOW LEVEL UTILITIES  ************************/
-
-static void
-szone_sleep(void)
-{
-	if (getenv("MallocErrorStop")) {
-		_malloc_printf(ASL_LEVEL_NOTICE, "*** sending SIGSTOP to help debug\n");
-		kill(getpid(), SIGSTOP);
-	} else if (getenv("MallocErrorSleep")) {
-		_malloc_printf(ASL_LEVEL_NOTICE, "*** sleeping to help debug\n");
-		sleep(3600); // to help debug
-	}
-}
-
-// msg prints after fmt, ...
-static NOINLINE void
-szone_error(szone_t *szone, int is_corruption, const char *msg, const void *ptr, const char *fmt, ...)
-{
-	va_list ap;
-	_SIMPLE_STRING b = _simple_salloc();
-
-	if (b) {
-		if (fmt) {
-			va_start(ap, fmt);
-			_simple_vsprintf(b, fmt, ap);
-			va_end(ap);
-		}
-		if (ptr) {
-			_simple_sprintf(b, "*** error for object %p: %s\n", ptr, msg);
-		} else {
-			_simple_sprintf(b, "*** error: %s\n", msg);
-		}
-		malloc_printf("%s*** set a breakpoint in malloc_error_break to debug\n", _simple_string(b));
-	} else {
-		/*
-		 * Should only get here if vm_allocate() can't get a single page of
-		 * memory, implying _simple_asl_log() would also fail.  So we just
-		 * print to the file descriptor.
-		 */
-		if (fmt) {
-			va_start(ap, fmt);
-			_malloc_vprintf(MALLOC_PRINTF_NOLOG, fmt, ap);
-			va_end(ap);
-		}
-		if (ptr) {
-			_malloc_printf(MALLOC_PRINTF_NOLOG, "*** error for object %p: %s\n", ptr, msg);
-		} else {
-			_malloc_printf(MALLOC_PRINTF_NOLOG, "*** error: %s\n", msg);
-		}
-		_malloc_printf(MALLOC_PRINTF_NOLOG, "*** set a breakpoint in malloc_error_break to debug\n");
-	}
-	malloc_error_break();
-#if DEBUG_MALLOC
-	szone_print(szone, 1);
-#endif
-	szone_sleep();
-	// Call abort() if this is a memory corruption error and the abort on
-	// corruption flag is set, or if any error should abort.
-	if ((is_corruption && (szone->debug_flags & SCALABLE_MALLOC_ABORT_ON_CORRUPTION)) ||
-		(szone->debug_flags & SCALABLE_MALLOC_ABORT_ON_ERROR)) {
-		CRSetCrashLogMessage(b ? _simple_string(b) : msg);
-		abort();
-	} else if (b) {
-		_simple_sfree(b);
-	}
-}
-
-static void
-protect(void *address, size_t size, unsigned protection, unsigned debug_flags)
-{
-	kern_return_t	err;
-
-	if (!(debug_flags & SCALABLE_MALLOC_DONT_PROTECT_PRELUDE)) {
-		err = mprotect((void *)((uintptr_t)address - vm_page_quanta_size), vm_page_quanta_size, protection);
-		if (err) {
-			malloc_printf("*** can't protect(%p) region for prelude guard page at %p\n",
-						  protection,(uintptr_t)address - vm_page_quanta_size);
-		}
-	}
-	if (!(debug_flags & SCALABLE_MALLOC_DONT_PROTECT_POSTLUDE)) {
-		err = mprotect((void *)(round_page_quanta(((uintptr_t)address + size))), vm_page_quanta_size, protection);
-		if (err) {
-			malloc_printf("*** can't protect(%p) region for postlude guard page at %p\n",
-						  protection, (uintptr_t)address + size);
-		}
-	}
-}
-
-static void *
-allocate_pages(szone_t *szone, size_t size, unsigned char align, unsigned debug_flags, int vm_page_label)
-{
-	boolean_t add_guard_pages = debug_flags & SCALABLE_MALLOC_ADD_GUARD_PAGES;
-	boolean_t purgeable = debug_flags & SCALABLE_MALLOC_PURGEABLE;
-	mach_vm_address_t vm_addr;
-	uintptr_t addr;
-	mach_vm_size_t allocation_size = round_page_quanta(size);
-	mach_vm_offset_t allocation_mask = ((mach_vm_offset_t)1 << align) - 1;
-	int alloc_flags = VM_FLAGS_ANYWHERE | VM_MAKE_TAG(vm_page_label);
-	kern_return_t kr;
-
-	if (!allocation_size) allocation_size = vm_page_quanta_size;
-	if (add_guard_pages) {
-		if (align > vm_page_quanta_shift) {
-			/* <rdar://problem/16601499> alignment greater than pagesize needs more work */
-			allocation_size += (1<<align) + vm_page_quanta_size;
-		} else {
-			allocation_size += 2 * vm_page_quanta_size;
-		}
-	}
-
-	if (purgeable) alloc_flags |= VM_FLAGS_PURGABLE;
-	if (allocation_size < size) // size_t arithmetic wrapped!
-		return NULL;
-
-	vm_addr = vm_page_quanta_size;
-	kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size,
-			allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
-			VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
-	if (kr) {
-		szone_error(szone, 0, "can't allocate region", NULL,
-				"*** mach_vm_map(size=%lu) failed (error code=%d)\n", size, kr);
-		return NULL;
-	}
-	addr = (uintptr_t)vm_addr;
-
-	if (add_guard_pages) {
-		if (align > vm_page_quanta_shift) {
-			/* <rdar://problem/16601499> calculate the first address inside the alignment padding
-			 * where we can place the guard page and still be aligned.
-			 *
-			 * |-----------------------------------------------------------|
-			 * |leading|gp|                  alloc                  |gp| t |
-			 * |-----------------------------------------------------------|
-			 */
-			uintptr_t alignaddr = ((addr + vm_page_quanta_size) + (1<<align) - 1) & ~((1<<align) - 1);
-			size_t leading = alignaddr - addr - vm_page_quanta_size;
-			size_t trailing = (1<<align) - vm_page_quanta_size - leading;
-
-			/* Unmap the excess area. */
-			kr = mach_vm_deallocate(mach_task_self(), addr, leading);
-			if (kr) {
-				szone_error(szone, 0, "can't unmap excess guard region", NULL,
-						"*** mach_vm_deallocate(addr=%p, size=%lu) failed (code=%d)", addr, leading, kr);
-				return NULL;
-			}
-
-			kr = mach_vm_deallocate(mach_task_self(), addr + allocation_size - trailing, trailing);
-			if (kr) {
-				szone_error(szone, 0, "can't unmap excess trailing guard region", NULL,
-						"*** mach_vm_deallocate(addr=%p, size=%lu) failed (code=%d)", addr + allocation_size - trailing, trailing, kr);
-				return NULL;
-			}
-
-			addr = alignaddr;
-		} else {
-			addr += vm_page_quanta_size;
-		}
-		protect((void *)addr, size, PROT_NONE, debug_flags);
-	}
-	return (void *)addr;
-}
-
-static void *
-allocate_pages_securely(szone_t *szone, size_t size, unsigned char align, int vm_page_label)
-{
-	mach_vm_address_t vm_addr;
-	uintptr_t addr;
-	mach_vm_size_t allocation_size = round_page_quanta(size);
-	mach_vm_offset_t allocation_mask = ((mach_vm_offset_t)1 << align) - 1;
-	int alloc_flags = VM_FLAGS_ANYWHERE | VM_MAKE_TAG(vm_page_label);
-	kern_return_t kr;
-
-	if (szone->debug_flags & DISABLE_ASLR) {
-		return allocate_pages(szone, size, align, 0, vm_page_label);
-	}
-
-	if (!allocation_size) allocation_size = vm_page_quanta_size;
-	if (allocation_size < size) // size_t arithmetic wrapped!
-		return NULL;
-
-retry:
-	vm_addr = entropic_address;
-	kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size,
-			allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
-			VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
-	if (kr == KERN_NO_SPACE) {
-		vm_addr = vm_page_quanta_size;
-		kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size,
-				allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
-				VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
-	}
-	if (kr) {
-		szone_error(szone, 0, "can't allocate region securely", NULL,
-				"*** mach_vm_map(size=%lu) failed (error code=%d)\n", size, kr);
-		return NULL;
-	}
-	addr = (uintptr_t)vm_addr;
-
-	// Don't allow allocation to rise above entropic_limit (for tidiness).
-	if (addr + allocation_size > entropic_limit) { // Exhausted current range?
-		uintptr_t t = entropic_address;
-		uintptr_t u = t - ENTROPIC_KABILLION;
-
-		if (u < t) { // provided we don't wrap, deallocate and retry, in the expanded entropic range
-			mach_vm_deallocate(mach_task_self(), vm_addr, allocation_size);
-			(void)__sync_bool_compare_and_swap(&entropic_address, t, u); // Just one reduction please
-			goto retry;
-		}
-		// fall through to use what we got
-	}
-
-	if (addr < entropic_address) { // we wrapped to find this allocation, expand the entropic range
-		uintptr_t t = entropic_address;
-		uintptr_t u = t - ENTROPIC_KABILLION;
-		if (u < t)
-			(void)__sync_bool_compare_and_swap(&entropic_address, t, u); // Just one reduction please
-		// fall through to use what we got
-	}
-	return (void *)addr;
-}
-
-static void
-deallocate_pages(szone_t *szone, void *addr, size_t size, unsigned debug_flags)
-{
-	boolean_t add_guard_pages = debug_flags & SCALABLE_MALLOC_ADD_GUARD_PAGES;
-	mach_vm_address_t vm_addr = (mach_vm_address_t)addr;
-	mach_vm_size_t allocation_size = size;
-	kern_return_t kr;
-
-	if (add_guard_pages) {
-		vm_addr -= vm_page_quanta_size;
-		allocation_size += 2 * vm_page_quanta_size;
-	}
-	kr = mach_vm_deallocate(mach_task_self(), vm_addr, allocation_size);
-	if (kr && szone)
-		szone_error(szone, 0, "Can't deallocate_pages region", addr, NULL);
-}
-
-/* On OS X we use MADV_FREE_REUSABLE, which signals the kernel to remove the given
- * pages from the memory statistics for our process. However, on returning that memory
- * to use we have to signal that it has been reused.
- *
- * On iOS MADV_FREE is used, which does no such tinkering and madvise_reuse_range is a
- * no-op.
- */
-#if TARGET_OS_EMBEDDED
-# define MADVISE_STYLE MADV_FREE
-#else
-# define MADVISE_STYLE MADV_FREE_REUSABLE
-#endif
-
-static int
-madvise_free_range(szone_t *szone, region_t r, uintptr_t pgLo, uintptr_t pgHi, uintptr_t *last)
-{
-	if (pgHi > pgLo) {
-		size_t len = pgHi - pgLo;
-
-		if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE) {
-			memset((void *)pgLo, SCRUBBLE_BYTE, len); // Scribble on MADV_FREEd memory
-		}
-
-#if TARGET_OS_EMBEDDED
-		if (last) {
-			if (*last == pgLo)
-				return 0;
-
-			*last = pgLo;
-		}
-#endif
-
-		MAGMALLOC_MADVFREEREGION((void *)szone, (void *)r, (void *)pgLo, len); // DTrace USDT Probe
-		if (-1 == madvise((void *)pgLo, len, MADVISE_STYLE)) {
-			/* -1 return: VM map entry change makes this unfit for reuse. Something evil lurks. */
-#if DEBUG_MADVISE
-			szone_error(szone, 0, "madvise_free_range madvise(..., MADV_FREE_REUSABLE) failed",
-						(void *)pgLo, "length=%d\n", len);
-#endif
-		}
-	}
-	return 0;
-}
-
-static int
-madvise_reuse_range(szone_t *szone, region_t r, uintptr_t pgLo, uintptr_t phHi)
-{
-#if !TARGET_OS_EMBEDDED
-	if (phHi > pgLo) {
-		size_t len = phHi - pgLo;
-
-		if (madvise((void *)pgLo, len, MADV_FREE_REUSE) == -1) {
-			/* -1 return: VM map entry change makes this unfit for reuse. Something evil lurks. */
-#if DEBUG_MADVISE
-			szone_error(szone, 0, "madvise_reuse_range madvise(..., MADV_FREE_REUSE) failed",
-					sparse_region, "length=%d\n", TINY_REGION_PAYLOAD_BYTES);
-#endif
-			return 1;
-		}
-	}
-#endif
-	return 0;
-}
-
-static kern_return_t
-_szone_default_reader(task_t task, vm_address_t address, vm_size_t size, void **ptr)
-{
-	*ptr = (void *)address;
-	return 0;
-}
-
-/*
- * These commpage routines provide fast access to the logical cpu number
- * of the calling processor assuming no pre-emption occurs.
- */
-
-static INLINE mag_index_t
-mag_get_thread_index(szone_t *szone)
-{
-	return _os_cpu_number() & (TINY_MAX_MAGAZINES - 1);
-}
-
-static magazine_t *
-mag_lock_zine_for_region_trailer(szone_t *szone, magazine_t *magazines, region_trailer_t *trailer, mag_index_t mag_index)
-{
-	mag_index_t refreshed_index;
-	magazine_t *mag_ptr = &(magazines[mag_index]);
-
-	// Take the lock  on entry.
-	SZONE_MAGAZINE_PTR_LOCK(szone, mag_ptr);
-
-	// Now in the time it took to acquire the lock, the region may have migrated
-	// from one magazine to another. In which case the magazine lock we obtained
-	// (namely magazines[mag_index].mag_lock) is stale. If so, keep on tryin' ...
-	while (mag_index != (refreshed_index = trailer->mag_index)) { // Note assignment
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, mag_ptr);
-
-		mag_index = refreshed_index;
-		mag_ptr = &(magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(szone, mag_ptr);
-	}
-
-	return mag_ptr;
-}
-
-/*******************************************************************************
- * Region hash implementation
- *
- * This is essentially a duplicate of the existing Large allocator hash, minus
- * the ability to remove entries.  The two should be combined eventually.
- ******************************************************************************/
-#pragma mark region hash
-
-/*
- * hash_lookup_region_no_lock - Scan a hash ring looking for an entry for a
- * given region.
- *
- * FIXME: If consecutive queries of the same region are likely, a one-entry
- * cache would likely be a significant performance win here.
- */
-static INLINE rgnhdl_t
-hash_lookup_region_no_lock(region_t *regions, size_t num_entries, size_t shift, region_t r) {
-	size_t	index, hash_index;
-	rgnhdl_t	entry;
-
-	if (!num_entries)
-		return 0;
-
-	// Multiplicative hash where the multiplier is a prime near (ULONG_MAX / phi). [phi = 1.618033...]
-	// Since the values of (((uintptr_t)r >> HASH_BLOCKS_ALIGN) are (roughly) an ascending sequence of integers,
-	// this hash works really well. See Knuth TAOCP, Vol. 3.
-#if __LP64__
-	index = hash_index = (((uintptr_t)r >> HASH_BLOCKS_ALIGN) * 11400714819323198549ULL) >> (64 - shift);
-#else
-	index = hash_index = (((uintptr_t)r >> HASH_BLOCKS_ALIGN) * 2654435761UL) >> (32 - shift);
-#endif
-	do {
-		entry = regions + index;
-		if (*entry == 0)
-			return 0;
-		if (*entry == r)
-			return entry;
-		if (++index == num_entries)
-			index = 0;
-	} while (index != hash_index);
-	return 0;
-}
-
-/*
- * hash_region_insert_no_lock - Insert a region into the hash ring.
- */
-static void
-hash_region_insert_no_lock(region_t *regions, size_t num_entries, size_t shift, region_t r) {
-	size_t	index, hash_index;
-	rgnhdl_t	entry;
-
-	// Multiplicative hash where the multiplier is a prime near (ULONG_MAX / phi). [phi = 1.618033...]
-	// Since the values of (((uintptr_t)r >> HASH_BLOCKS_ALIGN) are (roughly) an ascending sequence of integers,
-	// this hash works really well. See Knuth TAOCP, Vol. 3.
-#if __LP64__
-	index = hash_index = (((uintptr_t)r >> HASH_BLOCKS_ALIGN) * 11400714819323198549ULL) >> (64 - shift);
-#else
-	index = hash_index = (((uintptr_t)r >> HASH_BLOCKS_ALIGN) * 2654435761UL) >> (32 - shift);
-#endif
-	do {
-		entry = regions + index;
-		if (*entry == HASHRING_OPEN_ENTRY || *entry == HASHRING_REGION_DEALLOCATED) {
-			*entry = r;
-			return;
-		}
-		if (++index == num_entries)
-			index = 0;
-	} while (index != hash_index);
-}
-
-/*
- * hash_regions_alloc_no_lock - Allocate space for a number of entries.  This
- * must be a VM allocation as to avoid recursing between allocating a new small
- * region, and asking the small region to allocate space for the new list of
- * regions.
- */
-static region_t *
-hash_regions_alloc_no_lock(szone_t *szone, size_t num_entries)
-{
-	size_t	size = num_entries * sizeof(region_t);
-
-	return allocate_pages(szone, round_page_quanta(size), 0, 0, VM_MEMORY_MALLOC);
-}
-
-/*
- * hash_regions_grow_no_lock - Grow the hash ring, and rehash the entries.
- * Return the new region and new size to update the szone.  Do not deallocate
- * the old entries since someone may still be allocating them.
- */
-static region_t *
-hash_regions_grow_no_lock(szone_t *szone, region_t *regions, size_t old_size, size_t *mutable_shift,
-						  size_t *new_size)
-{
-	// double in size and allocate memory for the regions
-	*new_size = old_size + old_size;
-	*mutable_shift = *mutable_shift + 1;
-	region_t *new_regions = hash_regions_alloc_no_lock(szone, *new_size);
-
-	// rehash the entries into the new list
-	size_t index;
-	for (index = 0; index < old_size; ++index) {
-		region_t r = regions[index];
-		if (r != HASHRING_OPEN_ENTRY && r != HASHRING_REGION_DEALLOCATED)
-			hash_region_insert_no_lock(new_regions, *new_size, *mutable_shift, r);
-	}
-	return new_regions;
-}
-
-/*********************	FREE LIST UTILITIES  ************************/
-
-// A free list entry is comprised of a pair of pointers, previous and next.
-// These are used to implement a doubly-linked list, which permits efficient
-// extraction.
-//
-// Because the free list entries are previously freed objects, a misbehaved
-// program may write to a pointer after it has called free() on that pointer,
-// either by dereference or buffer overflow from an adjacent pointer. This write
-// would then corrupt the free list's previous and next pointers, leading to a
-// crash.  In order to detect this case, we take advantage of the fact that
-// malloc'd pointers are known to be at least 16 byte aligned, and thus have
-// at least 4 trailing zero bits.
-//
-// When an entry is added to the free list, a checksum of the previous and next
-// pointers is calculated and written to the high four bits of the respective
-// pointers.  Upon detection of an invalid checksum, an error is logged and NULL
-// is returned.  Since all code which un-checksums pointers checks for a NULL
-// return, a potentially crashing or malicious dereference is avoided at the
-// cost of leaking the corrupted block, and any subsequent blocks on the free
-// list of that size.
-
-static NOINLINE void
-free_list_checksum_botch(szone_t *szone, free_list_t *ptr)
-{
-	szone_error(szone, 1, "incorrect checksum for freed object "
-				"- object was probably modified after being freed.", ptr, NULL);
-}
-
-static INLINE uintptr_t free_list_gen_checksum(uintptr_t ptr)
-{
-	uint8_t chk;
-
-	chk  = (unsigned char)(ptr >>  0);
-	chk += (unsigned char)(ptr >>  8);
-	chk += (unsigned char)(ptr >> 16);
-	chk += (unsigned char)(ptr >> 24);
-#if  __LP64__
-	chk += (unsigned char)(ptr >> 32);
-	chk += (unsigned char)(ptr >> 40);
-	chk += (unsigned char)(ptr >> 48);
-	chk += (unsigned char)(ptr >> 56);
-#endif
-
-	return chk & (uintptr_t)0xF;
-}
-
-#define NYBBLE 4
-#if  __LP64__
-#define ANTI_NYBBLE (64 - NYBBLE)
-#else
-#define ANTI_NYBBLE (32 - NYBBLE)
-#endif
-
-static INLINE uintptr_t
-free_list_checksum_ptr(szone_t *szone, void *ptr)
-{
-	uintptr_t p = (uintptr_t)ptr;
-	return (p >> NYBBLE) | (free_list_gen_checksum(p ^ szone->cookie) << ANTI_NYBBLE); // compiles to rotate instruction
-}
-
-static INLINE void *
-free_list_unchecksum_ptr(szone_t *szone, ptr_union *ptr)
-{
-	ptr_union p;
-	uintptr_t t = ptr->u;
-
-	t = (t << NYBBLE) | (t >> ANTI_NYBBLE); // compiles to rotate instruction
-	p.u = t &  ~(uintptr_t)0xF;
-
-	if ((t & (uintptr_t)0xF) != free_list_gen_checksum(p.u ^ szone->cookie))
-	{
-		free_list_checksum_botch(szone, (free_list_t *)ptr);
-		return NULL;
-	}
-	return p.p;
-}
-
-#undef ANTI_NYBBLE
-#undef NYBBLE
-
-static unsigned
-free_list_count(szone_t *szone, free_list_t *ptr)
-{
-	unsigned	count = 0;
-
-	while (ptr) {
-		count++;
-		ptr = free_list_unchecksum_ptr(szone, &ptr->next);
-	}
-	return count;
-}
-
-static INLINE void
-recirc_list_extract(szone_t *szone, magazine_t *mag_ptr, region_trailer_t *node)
-{
-	// excise node from list
-	if (NULL == node->prev)
-		mag_ptr->firstNode = node->next;
-	else
-		node->prev->next = node->next;
-
-	if (NULL == node->next)
-		mag_ptr->lastNode = node->prev;
-	else
-		node->next->prev = node->prev;
-
-	mag_ptr->recirculation_entries--;
-}
-
-static INLINE void
-recirc_list_splice_last(szone_t *szone, magazine_t *mag_ptr, region_trailer_t *node)
-{
-	if (NULL == mag_ptr->lastNode) {
-		mag_ptr->firstNode = node;
-		node->prev = NULL;
-	} else {
-		node->prev = mag_ptr->lastNode;
-		mag_ptr->lastNode->next = node;
-	}
-	mag_ptr->lastNode = node;
-	node->next = NULL;
-	node->recirc_suitable = FALSE;
-	mag_ptr->recirculation_entries++;
-}
-
-static INLINE void
-recirc_list_splice_first(szone_t *szone, magazine_t *mag_ptr, region_trailer_t *node)
-{
-	if (NULL == mag_ptr->firstNode) {
-		mag_ptr->lastNode = node;
-		node->next = NULL;
-	} else {
-		node->next = mag_ptr->firstNode;
-		mag_ptr->firstNode->prev = node;
-	}
-	mag_ptr->firstNode = node;
-	node->prev = NULL;
-	node->recirc_suitable = FALSE;
-	mag_ptr->recirculation_entries++;
-}
-
-/* Macros used to manipulate the uint32_t quantity mag_bitmap. */
-
-/* BITMAPV variants are used by tiny. */
-#if defined(__LP64__)
-// assert(NUM_SLOTS == 64) in which case (slot >> 5) is either 0 or 1
-#define BITMAPV_SET(bitmap,slot) 	(bitmap[(slot) >> 5] |= 1 << ((slot) & 31))
-#define BITMAPV_CLR(bitmap,slot) 	(bitmap[(slot) >> 5] &= ~ (1 << ((slot) & 31)))
-#define BITMAPV_BIT(bitmap,slot)	((bitmap[(slot) >> 5] >> ((slot) & 31)) & 1)
-#define BITMAPV_CTZ(bitmap)		(__builtin_ctzl(bitmap))
-#else
-// assert(NUM_SLOTS == 32) in which case (slot >> 5) is always 0, so code it that way
-#define BITMAPV_SET(bitmap,slot) 	(bitmap[0] |= 1 << (slot))
-#define BITMAPV_CLR(bitmap,slot)	(bitmap[0] &= ~ (1 << (slot)))
-#define BITMAPV_BIT(bitmap,slot) 	((bitmap[0] >> (slot)) & 1)
-#define BITMAPV_CTZ(bitmap)		(__builtin_ctz(bitmap))
-#endif
-
-/* BITMAPN is used by small. (slot >> 5) takes on values from 0 to 7. */
-#define BITMAPN_SET(bitmap,slot) 	(bitmap[(slot) >> 5] |= 1 << ((slot) & 31))
-#define BITMAPN_CLR(bitmap,slot) 	(bitmap[(slot) >> 5] &= ~ (1 << ((slot) & 31)))
-#define BITMAPN_BIT(bitmap,slot)	((bitmap[(slot) >> 5] >> ((slot) & 31)) & 1)
-
-/* returns bit # of least-significant one bit, starting at 0 (undefined if !bitmap) */
-#define BITMAP32_CTZ(bitmap)		(__builtin_ctz(bitmap[0]))
-
-/*********************	TINY FREE LIST UTILITIES	************************/
-
-// We encode the meta-headers as follows:
-// Each quantum has an associated set of 2 bits:
-// block_header when 1 says this block is the beginning of a block
-// in_use when 1 says this block is in use
-// so a block in use of size 3 is 1-1 0-X 0-X
-// for a free block TINY_FREE_SIZE(ptr) carries the size and the bits are 1-0 X-X X-X
-// for a block middle the bits are 0-0
-
-// We store the meta-header bit arrays by interleaving them 32 bits at a time.
-// Initial 32 bits of block_header, followed by initial 32 bits of in_use, followed
-// by next 32 bits of block_header, followed by next 32 bits of in_use, etc.
-// This localizes memory references thereby reducing cache and TLB pressures.
-
-static INLINE void
-BITARRAY_SET(uint32_t *bits, msize_t index)
-{
-	// index >> 5 identifies the uint32_t to manipulate in the conceptually contiguous bits array
-	// (index >> 5) << 1 identifies the uint32_t allowing for the actual interleaving
-	bits[(index >> 5) << 1] |= (1 << (index & 31));
-}
-
-static INLINE void
-BITARRAY_CLR(uint32_t *bits, msize_t index)
-{
-	bits[(index >> 5) << 1] &= ~(1 << (index & 31));
-}
-
-static INLINE boolean_t
-BITARRAY_BIT(uint32_t *bits, msize_t index)
-{
-	return ((bits[(index >> 5) << 1]) >> (index & 31)) & 1;
-}
-
-#if 0
-static INLINE void	bitarray_mclr(uint32_t *bits, unsigned start, unsigned end) ALWAYSINLINE;
-
-static INLINE void
-bitarray_mclr(uint32_t *bits, unsigned start, unsigned end)
-{
-	// start >> 5 identifies the uint32_t to manipulate in the conceptually contiguous bits array
-	// (start >> 5) << 1 identifies the uint32_t allowing for the actual interleaving
-	uint32_t	*addr = bits + ((start >> 5) << 1);
-
-	uint32_t	span = end - start;
-	start = start & 31;
-	end = start + span;
-
-	if (end > 31) {
-		addr[0] &= (0xFFFFFFFFU >> (31 - start)) >> 1;
-		addr[2] &= (0xFFFFFFFFU << (end - 32));
-	} else {
-		unsigned mask = (0xFFFFFFFFU >> (31 - start)) >> 1;
-		mask |= (0xFFFFFFFFU << end);
-		addr[0] &= mask;
-	}
-}
-#endif
-
-/*
- * Obtain the size of a free tiny block (in msize_t units).
- */
-static msize_t
-get_tiny_free_size(const void *ptr)
-{
-	void	*next_block = (void *)((uintptr_t)ptr + TINY_QUANTUM);
-	void	*region_end = TINY_REGION_END(TINY_REGION_FOR_PTR(ptr));
-
-	// check whether the next block is outside the tiny region or a block header
-	// if so, then the size of this block is one, and there is no stored size.
-	if (next_block < region_end)
-	{
-		uint32_t	*next_header = TINY_BLOCK_HEADER_FOR_PTR(next_block);
-		msize_t		next_index  = TINY_INDEX_FOR_PTR(next_block);
-
-		if (!BITARRAY_BIT(next_header, next_index))
-			return TINY_FREE_SIZE(ptr);
-	}
-	return 1;
-}
-
-/*
- * Get the size of the previous free block, which is stored in the last two
- * bytes of the block.  If the previous block is not free, then the result is
- * undefined.
- */
-static msize_t
-get_tiny_previous_free_msize(const void *ptr)
-{
-	// check whether the previous block is in the tiny region and a block header
-	// if so, then the size of the previous block is one, and there is no stored
-	// size.
-	if (ptr != TINY_REGION_FOR_PTR(ptr))
-	{
-		void		*prev_block = (void *)((uintptr_t)ptr - TINY_QUANTUM);
-		uint32_t	*prev_header = TINY_BLOCK_HEADER_FOR_PTR(prev_block);
-		msize_t		prev_index  = TINY_INDEX_FOR_PTR(prev_block);
-		if (BITARRAY_BIT(prev_header, prev_index))
-			return 1;
-		return TINY_PREVIOUS_MSIZE(ptr);
-	}
-	// don't read possibly unmapped memory before the beginning of the region
-	return 0;
-}
-
-static INLINE msize_t
-get_tiny_meta_header(const void *ptr, boolean_t *is_free)
-{
-	// returns msize and is_free
-	// may return 0 for the msize component (meaning 65536)
-	uint32_t	*block_header;
-	msize_t	index;
-
-	block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	index = TINY_INDEX_FOR_PTR(ptr);
-
-	msize_t midx = (index >> 5) << 1;
-	uint32_t mask = 1 << (index & 31);
-	*is_free = 0;
-	if (0 == (block_header[midx] & mask)) // if (!BITARRAY_BIT(block_header, index))
-		return 0;
-	if (0 == (block_header[midx + 1] & mask)) { // if (!BITARRAY_BIT(in_use, index))
-		*is_free = 1;
-		return get_tiny_free_size(ptr);
-	}
-
-	// index >> 5 identifies the uint32_t to manipulate in the conceptually contiguous bits array
-	// (index >> 5) << 1 identifies the uint32_t allowing for the actual interleaving
-#if defined(__LP64__)
-	// The return value, msize, is computed as the distance to the next 1 bit in block_header.
-	// That's guaranteed to be somewhwere in the next 64 bits. And those bits could span three
-	// uint32_t block_header elements. Collect the bits into a single uint64_t and measure up with ffsl.
-	uint32_t	*addr = ((uint32_t *)block_header) + ((index >> 5) << 1);
-	uint32_t	bitidx = index & 31;
-	uint64_t	word_lo = addr[0];
-	uint64_t	word_mid = addr[2];
-	uint64_t	word_hi = addr[4];
-	uint64_t	word_lomid = (word_lo >> bitidx) | (word_mid << (32 - bitidx));
-	uint64_t	word = bitidx ? word_lomid | (word_hi << (64 - bitidx)) : word_lomid;
-	uint32_t	result = __builtin_ffsl(word >> 1);
-#else
-	// The return value, msize, is computed as the distance to the next 1 bit in block_header.
-	// That's guaranteed to be somwhwere in the next 32 bits. And those bits could span two
-	// uint32_t block_header elements. Collect the bits into a single uint32_t and measure up with ffs.
-	uint32_t	*addr = ((uint32_t *)block_header) + ((index >> 5) << 1);
-	uint32_t	bitidx = index & 31;
-	uint32_t	word = bitidx ? (addr[0] >> bitidx) | (addr[2] << (32 - bitidx)) : addr[0];
-	uint32_t	result = __builtin_ffs(word >> 1);
-#endif
-	return result;
-}
-
-static INLINE void
-set_tiny_meta_header_in_use(const void *ptr, msize_t msize)
-{
-	uint32_t	*block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	msize_t	index = TINY_INDEX_FOR_PTR(ptr);
-	msize_t	clr_msize = msize - 1;
-	msize_t	midx = (index >> 5) << 1;
-	uint32_t	val = (1 << (index & 31));
-
-#if DEBUG_MALLOC
-	if (msize >= NUM_TINY_SLOTS)
-		malloc_printf("set_tiny_meta_header_in_use() invariant broken %p %d\n", ptr, msize);
-	if ((unsigned)index + (unsigned)msize > 0x10000)
-		malloc_printf("set_tiny_meta_header_in_use() invariant broken (2) %p %d\n", ptr, msize);
-#endif
-
-	block_header[midx] |= val; // BITARRAY_SET(block_header, index);
-	block_header[midx + 1] |= val; // BITARRAY_SET(in_use, index);
-
-	// bitarray_mclr(block_header, index, end_bit);
-	// bitarray_mclr(in_use, index, end_bit);
-
-	index++;
-	midx = (index >> 5) << 1;
-
-	unsigned	start = index & 31;
-	unsigned	end = start + clr_msize;
-
-#if defined(__LP64__)
-	if (end > 63) {
-		unsigned mask0 = (0xFFFFFFFFU >> (31 - start)) >> 1;
-		unsigned mask1 = (0xFFFFFFFFU << (end - 64));
-		block_header[midx + 0] &= mask0; // clear header
-		block_header[midx + 1] &= mask0; // clear in_use
-		block_header[midx + 2] = 0; // clear header
-		block_header[midx + 3] = 0; // clear in_use
-		block_header[midx + 4] &= mask1; // clear header
-		block_header[midx + 5] &= mask1; // clear in_use
-	} else
-#endif
-		if (end > 31) {
-			unsigned mask0 = (0xFFFFFFFFU >> (31 - start)) >> 1;
-			unsigned mask1 = (0xFFFFFFFFU << (end - 32));
-			block_header[midx + 0] &= mask0;
-			block_header[midx + 1] &= mask0;
-			block_header[midx + 2] &= mask1;
-			block_header[midx + 3] &= mask1;
-		} else {
-			unsigned mask = (0xFFFFFFFFU >> (31 - start)) >> 1;
-			mask |= (0xFFFFFFFFU << end);
-			block_header[midx + 0] &= mask;
-			block_header[midx + 1] &= mask;
-		}
-
-	// we set the block_header bit for the following block to reaffirm next block is a block
-	index += clr_msize;
-	midx = (index >> 5) << 1;
-	val = (1 << (index & 31));
-	block_header[midx] |= val; // BITARRAY_SET(block_header, (index+clr_msize));
-#if DEBUG_MALLOC
-	{
-		boolean_t ff;
-		msize_t	mf;
-
-		mf = get_tiny_meta_header(ptr, &ff);
-		if (msize != mf) {
-			malloc_printf("setting header for tiny in_use %p : %d\n", ptr, msize);
-			malloc_printf("reading header for tiny %p : %d %d\n", ptr, mf, ff);
-		}
-	}
-#endif
-}
-
-static INLINE void
-set_tiny_meta_header_in_use_1(const void *ptr) // As above with msize == 1
-{
-	uint32_t	*block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	msize_t	index = TINY_INDEX_FOR_PTR(ptr);
-	msize_t	midx = (index >> 5) << 1;
-	uint32_t	val = (1 << (index & 31));
-
-	block_header[midx] |= val; // BITARRAY_SET(block_header, index);
-	block_header[midx + 1] |= val; // BITARRAY_SET(in_use, index);
-
-	index++;
-	midx = (index >> 5) << 1;
-	val = (1 << (index & 31));
-
-	block_header[midx] |= val; // BITARRAY_SET(block_header, (index+clr_msize))
-}
-
-static INLINE void
-set_tiny_meta_header_middle(const void *ptr)
-{
-	// indicates this block is in the middle of an in use block
-	uint32_t	*block_header;
-	uint32_t	*in_use;
-	msize_t	index;
-
-	block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	in_use = TINY_INUSE_FOR_HEADER(block_header);
-	index = TINY_INDEX_FOR_PTR(ptr);
-
-	BITARRAY_CLR(block_header, index);
-	BITARRAY_CLR(in_use, index);
-}
-
-static INLINE void
-set_tiny_meta_header_free(const void *ptr, msize_t msize)
-{
-	// !msize is acceptable and means 65536
-	uint32_t	*block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	msize_t	index = TINY_INDEX_FOR_PTR(ptr);
-	msize_t	midx = (index >> 5) << 1;
-	uint32_t	val = (1 << (index & 31));
-
-#if DEBUG_MALLOC
-	if ((unsigned)index + (unsigned)msize > 0x10000) {
-		malloc_printf("setting header for tiny free %p msize too large: %d\n", ptr, msize);
-	}
-#endif
-
-	block_header[midx] |= val; // BITARRAY_SET(block_header, index);
-	block_header[midx + 1] &= ~val; // BITARRAY_CLR(in_use, index);
-
-	// mark the end of this block if msize is > 1.  For msize == 0, the whole
-	// region is free, so there is no following block. For msize == 1, there is
-	// no space to write the size on 64 bit systems.  The size for 1 quantum
-	// blocks is computed from the metadata bitmaps.
-	if (msize > 1) {
-		void	*follower = FOLLOWING_TINY_PTR(ptr, msize);
-		TINY_PREVIOUS_MSIZE(follower) = msize;
-		TINY_FREE_SIZE(ptr) = msize;
-	}
-	if (msize == 0) {
-		TINY_FREE_SIZE(ptr) = msize;
-	}
-#if DEBUG_MALLOC
-	boolean_t	ff;
-	msize_t	mf = get_tiny_meta_header(ptr, &ff);
-	if ((msize != mf) || !ff) {
-		malloc_printf("setting header for tiny free %p : %u\n", ptr, msize);
-		malloc_printf("reading header for tiny %p : %u %u\n", ptr, mf, ff);
-	}
-#endif
-}
-
-static INLINE boolean_t
-tiny_meta_header_is_free(const void *ptr)
-{
-	uint32_t	*block_header;
-	uint32_t	*in_use;
-	msize_t	index;
-
-	block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	in_use = TINY_INUSE_FOR_HEADER(block_header);
-	index = TINY_INDEX_FOR_PTR(ptr);
-	if (!BITARRAY_BIT(block_header, index))
-		return 0;
-	return !BITARRAY_BIT(in_use, index);
-}
-
-static INLINE void *
-tiny_previous_preceding_free(void *ptr, msize_t *prev_msize)
-{
-	// returns the previous block, assuming and verifying it's free
-	uint32_t	*block_header;
-	uint32_t	*in_use;
-	msize_t	index;
-	msize_t	previous_msize;
-	msize_t	previous_index;
-	void	*previous_ptr;
-
-	block_header = TINY_BLOCK_HEADER_FOR_PTR(ptr);
-	in_use = TINY_INUSE_FOR_HEADER(block_header);
-	index = TINY_INDEX_FOR_PTR(ptr);
-
-	if (!index)
-		return NULL;
-	if ((previous_msize = get_tiny_previous_free_msize(ptr)) > index)
-		return NULL;
-
-	previous_index = index - previous_msize;
-	previous_ptr = (void *)((uintptr_t)TINY_REGION_FOR_PTR(ptr) + TINY_BYTES_FOR_MSIZE(previous_index));
-	if (!BITARRAY_BIT(block_header, previous_index))
-		return NULL;
-	if (BITARRAY_BIT(in_use, previous_index))
-		return NULL;
-	if (get_tiny_free_size(previous_ptr) != previous_msize)
-		return NULL;
-
-	// conservative check did match true check
-	*prev_msize = previous_msize;
-	return previous_ptr;
-}
-
-/*
- * Adds an item to the proper free list, and also marks the meta-header of the
- * block properly.
- * Assumes szone has been locked
- */
-static void
-tiny_free_list_add_ptr(szone_t *szone, magazine_t *tiny_mag_ptr, void *ptr, msize_t msize)
-{
-	grain_t	slot = (!msize || (msize >= NUM_TINY_SLOTS)) ? NUM_TINY_SLOTS - 1 : msize - 1;
-	free_list_t	*free_ptr = ptr;
-	free_list_t	*free_head = tiny_mag_ptr->mag_free_list[slot];
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
-	}
-	if (((uintptr_t)ptr) & (TINY_QUANTUM - 1)) {
-		szone_error(szone, 1, "tiny_free_list_add_ptr: Unaligned ptr", ptr, NULL);
-	}
-#endif
-	set_tiny_meta_header_free(ptr, msize);
-	if (free_head) {
-#if DEBUG_MALLOC
-		if (free_list_unchecksum_ptr(szone, &free_head->previous)) {
-			szone_error(szone, 1, "tiny_free_list_add_ptr: Internal invariant broken (free_head->previous)", ptr,
-						"ptr=%p slot=%d free_head=%p previous=%p\n", ptr, slot, (void *)free_head, free_head->previous.p);
-		}
-		if (! tiny_meta_header_is_free(free_head)) {
-			szone_error(szone, 1, "tiny_free_list_add_ptr: Internal invariant broken (free_head is not a free pointer)", ptr,
-						"ptr=%p slot=%d free_head=%p\n", ptr, slot, (void *)free_head);
-		}
-#endif
-		free_head->previous.u = free_list_checksum_ptr(szone, free_ptr);
-	} else {
-		BITMAPV_SET(tiny_mag_ptr->mag_bitmap, slot);
-	}
-	free_ptr->previous.u = free_list_checksum_ptr(szone, NULL);
-	free_ptr->next.u = free_list_checksum_ptr(szone, free_head);
-
-	tiny_mag_ptr->mag_free_list[slot] = free_ptr;
-}
-
-/*
- * Removes the item pointed to by ptr in the proper free list.
- * Assumes szone has been locked
- */
-static void
-tiny_free_list_remove_ptr(szone_t *szone, magazine_t *tiny_mag_ptr, void *ptr, msize_t msize)
-{
-	grain_t	slot = (!msize || (msize >= NUM_TINY_SLOTS)) ? NUM_TINY_SLOTS - 1 : msize - 1;
-	free_list_t	*free_ptr = ptr, *next, *previous;
-
-	next = free_list_unchecksum_ptr(szone, &free_ptr->next);
-	previous = free_list_unchecksum_ptr(szone, &free_ptr->previous);
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("In %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
-	}
-#endif
-	if (!previous) {
-		// The block to remove is the head of the free list
-#if DEBUG_MALLOC
-		if (tiny_mag_ptr->mag_free_list[slot] != ptr) {
-			szone_error(szone, 1, "tiny_free_list_remove_ptr: Internal invariant broken (tiny_mag_ptr->mag_free_list[slot])", ptr,
-						"ptr=%p slot=%d msize=%d tiny_mag_ptr->mag_free_list[slot]=%p\n",
-						ptr, slot, msize, (void *)tiny_mag_ptr->mag_free_list[slot]);
-			return;
-		}
-#endif
-		tiny_mag_ptr->mag_free_list[slot] = next;
-		if (!next) BITMAPV_CLR(tiny_mag_ptr->mag_bitmap, slot);
-	} else {
-		// We know free_ptr is already checksummed, so we don't need to do it
-		// again.
-		previous->next = free_ptr->next;
-	}
-	if (next) {
-		// We know free_ptr is already checksummed, so we don't need to do it
-		// again.
-		next->previous = free_ptr->previous;
-	}
-}
-
-/*
- * tiny_region_for_ptr_no_lock - Returns the tiny region containing the pointer,
- * or NULL if not found.
- */
-static INLINE region_t
-tiny_region_for_ptr_no_lock(szone_t *szone, const void *ptr)
-{
-	rgnhdl_t r = hash_lookup_region_no_lock(szone->tiny_region_generation->hashed_regions,
-											szone->tiny_region_generation->num_regions_allocated,
-											szone->tiny_region_generation->num_regions_allocated_shift,
-											TINY_REGION_FOR_PTR(ptr));
-	return r ? *r : r;
-}
-
-static void
-tiny_finalize_region(szone_t *szone, magazine_t *tiny_mag_ptr) {
-	void      *last_block, *previous_block;
-	uint32_t  *last_header;
-	msize_t   last_msize, previous_msize, last_index;
-
-	// It is possible that the block prior to the last block in the region has
-	// been free'd, but was not coalesced with the free bytes at the end of the
-	// block, since we treat the bytes at the end of the region as "in use" in
-	// the meta headers. Attempt to coalesce the last block with the previous
-	// block, so we don't violate the "no consecutive free blocks" invariant.
-	//
-	// FIXME: Need to investigate how much work would be required to increase
-	//        'mag_bytes_free_at_end' when freeing the preceding block, rather
-	//        than performing this workaround.
-	//
-
-	if (tiny_mag_ptr->mag_bytes_free_at_end) {
-		last_block = (void *)
-		((uintptr_t)TINY_REGION_END(tiny_mag_ptr->mag_last_region) - tiny_mag_ptr->mag_bytes_free_at_end);
-		last_msize = TINY_MSIZE_FOR_BYTES(tiny_mag_ptr->mag_bytes_free_at_end);
-		last_header = TINY_BLOCK_HEADER_FOR_PTR(last_block);
-		last_index  = TINY_INDEX_FOR_PTR(last_block);
-
-		// Before anything we transform any remaining mag_bytes_free_at_end into a
-		// regular free block.  We take special care here to update the bitfield
-		// information, since we are bypassing the normal free codepath.  If there
-		// is more than one quanta worth of memory in mag_bytes_free_at_end, then
-		// there will be two block headers:
-		// 1) header for the free space at end, msize = 1
-		// 2) header inserted by set_tiny_meta_header_in_use after block
-		// We must clear the second one so that when the free block's size is
-		// queried, we do not think the block is only 1 quantum in size because
-		// of the second set header bit.
-		if (last_index != (NUM_TINY_BLOCKS - 1))
-			BITARRAY_CLR(last_header, (last_index + 1));
-
-		previous_block = tiny_previous_preceding_free(last_block, &previous_msize);
-		if (previous_block) {
-			set_tiny_meta_header_middle(last_block);
-			tiny_free_list_remove_ptr(szone, tiny_mag_ptr, previous_block, previous_msize);
-			last_block = previous_block;
-			last_msize += previous_msize;
-		}
-
-		// splice last_block into the free list
-		tiny_free_list_add_ptr(szone, tiny_mag_ptr, last_block, last_msize);
-		tiny_mag_ptr->mag_bytes_free_at_end = 0;
-	}
-
-#if ASLR_INTERNAL
-	// Coalesce the big free block at start with any following free blocks
-	if (tiny_mag_ptr->mag_bytes_free_at_start) {
-		last_block = TINY_REGION_ADDRESS(tiny_mag_ptr->mag_last_region);
-		last_msize = TINY_MSIZE_FOR_BYTES(tiny_mag_ptr->mag_bytes_free_at_start);
-
-		void *next_block = (void *) ((uintptr_t)last_block + tiny_mag_ptr->mag_bytes_free_at_start);
-
-		// clear the in use bit we were using to mark the end of the big start block
-		set_tiny_meta_header_middle((void *)((uintptr_t)next_block - TINY_QUANTUM));
-
-		// Coalesce the big start block with any following free blocks
-		if (tiny_meta_header_is_free(next_block)) {
-			msize_t next_msize = get_tiny_free_size(next_block);
-			set_tiny_meta_header_middle(next_block);
-			tiny_free_list_remove_ptr(szone, tiny_mag_ptr, next_block, next_msize);
-			last_msize += next_msize;
-		}
-
-		// splice last_block into the free list
-		tiny_free_list_add_ptr(szone, tiny_mag_ptr, last_block, last_msize);
-		tiny_mag_ptr->mag_bytes_free_at_start = 0;
-	}
-#endif
-
-	tiny_mag_ptr->mag_last_region = NULL;
-}
-
-static int
-tiny_free_detach_region(szone_t *szone, magazine_t *tiny_mag_ptr, region_t r) {
-	uintptr_t	start = (uintptr_t)TINY_REGION_ADDRESS(r);
-	uintptr_t	current = start;
-	uintptr_t	limit =  (uintptr_t)TINY_REGION_END(r);
-	boolean_t	is_free;
-	msize_t	msize;
-	int		total_alloc = 0;
-
-	while (current < limit) {
-		msize = get_tiny_meta_header((void *)current, &is_free);
-		if (is_free && !msize && (current == start)) {
-			// first block is all free
-			break;
-		}
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_printf("*** tiny_free_detach_region error with %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			break;
-		}
-		if (is_free) {
-			tiny_free_list_remove_ptr(szone, tiny_mag_ptr, (void *)current, msize);
-		} else {
-			total_alloc++;
-		}
-		current += TINY_BYTES_FOR_MSIZE(msize);
-	}
-	return total_alloc;
-}
-
-static size_t
-tiny_free_reattach_region(szone_t *szone, magazine_t *tiny_mag_ptr, region_t r) {
-	uintptr_t	start = (uintptr_t)TINY_REGION_ADDRESS(r);
-	uintptr_t	current = start;
-	uintptr_t	limit =  (uintptr_t)TINY_REGION_END(r);
-	boolean_t	is_free;
-	msize_t	msize;
-	size_t	total_alloc = 0;
-
-	while (current < limit) {
-		msize = get_tiny_meta_header((void *)current, &is_free);
-		if (is_free && !msize && (current == start)) {
-			// first block is all free
-			break;
-		}
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_printf("*** tiny_free_reattach_region error with %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			break;
-		}
-		if (is_free) {
-			tiny_free_list_add_ptr(szone, tiny_mag_ptr, (void *)current, msize);
-		} else {
-			total_alloc += TINY_BYTES_FOR_MSIZE(msize);
-		}
-		current += TINY_BYTES_FOR_MSIZE(msize);
-	}
-	return total_alloc;
-}
-
-typedef struct {
-	uint8_t pnum, size;
-} tiny_pg_pair_t;
-
-static void NOINLINE /* want private stack frame for automatic array */
-tiny_free_scan_madvise_free(szone_t *szone, magazine_t *depot_ptr, region_t r) {
-	uintptr_t	start = (uintptr_t)TINY_REGION_ADDRESS(r);
-	uintptr_t	current = start;
-	uintptr_t	limit =  (uintptr_t)TINY_REGION_END(r);
-	boolean_t	is_free;
-	msize_t	msize;
-	tiny_pg_pair_t advisory[((TINY_REGION_PAYLOAD_BYTES + vm_page_quanta_size - 1) >> vm_page_quanta_shift) >> 1]; // 256bytes stack allocated
-	int		advisories = 0;
-
-	// Scan the metadata identifying blocks which span one or more pages. Mark the pages MADV_FREE taking care to preserve free list
-	// management data.
-	while (current < limit) {
-		msize = get_tiny_meta_header((void *)current, &is_free);
-		if (is_free && !msize && (current == start)) {
-			// first block is all free
-#if DEBUG_MALLOC
-			malloc_printf("*** tiny_free_scan_madvise_free first block is all free! %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			uintptr_t pgLo = round_page_quanta(start + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(start + TINY_REGION_SIZE - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				advisory[advisories].pnum = (pgLo - start) >> vm_page_quanta_shift;
-				advisory[advisories].size = (pgHi - pgLo) >> vm_page_quanta_shift;
-				advisories++;
-			}
-			break;
-		}
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_printf("*** tiny_free_scan_madvise_free error with %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			break;
-		}
-		if (is_free) {
-			uintptr_t pgLo = round_page_quanta(current + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(current + TINY_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				advisory[advisories].pnum = (pgLo - start) >> vm_page_quanta_shift;
-				advisory[advisories].size = (pgHi - pgLo) >> vm_page_quanta_shift;
-				advisories++;
-			}
-		}
-		current += TINY_BYTES_FOR_MSIZE(msize);
-	}
-
-	if (advisories > 0) {
-		int i;
-
-		// So long as the following hold for this region:
-		// (1) No malloc()'s are ever performed from the depot (hence free pages remain free,)
-		// (2) The region is not handed over to a per-CPU magazine (where malloc()'s could be performed),
-		// (3) The entire region is not mumap()'d (so the madvise's are applied to the intended addresses),
-		// then the madvise opportunities collected just above can be applied outside all locks.
-		// (1) is ensured by design, (2) and (3) are ensured by bumping the globally visible counter node->pinned_to_depot.
-
-		OSAtomicIncrement32Barrier(&(REGION_TRAILER_FOR_TINY_REGION(r)->pinned_to_depot));
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, depot_ptr);
-		for (i = 0; i < advisories; ++i) {
-			uintptr_t addr = (advisory[i].pnum << vm_page_quanta_shift) + start;
-			size_t size = advisory[i].size << vm_page_quanta_shift;
-
-			madvise_free_range(szone, r, addr, addr + size, NULL);
-		}
-		SZONE_MAGAZINE_PTR_LOCK(szone, depot_ptr);
-		OSAtomicDecrement32Barrier(&(REGION_TRAILER_FOR_TINY_REGION(r)->pinned_to_depot));
-	}
-}
-
-static region_t
-tiny_free_try_depot_unmap_no_lock(szone_t *szone, magazine_t *depot_ptr, region_trailer_t *node)
-{
-	if (0 < node->bytes_used ||
-		0 < node->pinned_to_depot ||
-		depot_ptr->recirculation_entries < (szone->num_tiny_magazines * 2)) {
-		return NULL;
-	}
-
-	// disconnect node from Depot
-	recirc_list_extract(szone, depot_ptr, node);
-
-	// Iterate the region pulling its free entries off the (locked) Depot's free list
-	region_t sparse_region = TINY_REGION_FOR_PTR(node);
-	int objects_in_use = tiny_free_detach_region(szone, depot_ptr, sparse_region);
-
-	if (0 == objects_in_use) {
-		// Invalidate the hash table entry for this region with HASHRING_REGION_DEALLOCATED.
-		// Using HASHRING_REGION_DEALLOCATED preserves the collision chain, using HASHRING_OPEN_ENTRY (0) would not.
-		rgnhdl_t pSlot = hash_lookup_region_no_lock(szone->tiny_region_generation->hashed_regions,
-													szone->tiny_region_generation->num_regions_allocated,
-													szone->tiny_region_generation->num_regions_allocated_shift, sparse_region);
-		if (NULL == pSlot) {
-			szone_error(szone, 1, "tiny_free_try_depot_unmap_no_lock hash lookup failed:", NULL, "%p\n", sparse_region);
-			return NULL;
-		}
-		*pSlot = HASHRING_REGION_DEALLOCATED;
-		depot_ptr->num_bytes_in_magazine -= TINY_REGION_PAYLOAD_BYTES;
-		__sync_fetch_and_add( &(szone->num_tiny_regions_dealloc), 1); // Atomically increment num_tiny_regions_dealloc
-
-		// Caller will transfer ownership of the region back to the OS with no locks held
-		MAGMALLOC_DEALLOCREGION((void *)szone, (void *)sparse_region, TINY_REGION_SIZE); // DTrace USDT Probe
-		return sparse_region;
-	} else {
-		szone_error(szone, 1, "tiny_free_try_depot_unmap_no_lock objects_in_use not zero:", NULL, "%d\n", objects_in_use);
-		return NULL;
-	}
-}
-
-static boolean_t
-tiny_free_do_recirc_to_depot(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index)
-{
-	// The entire magazine crossed the "emptiness threshold". Transfer a region
-	// from this magazine to the Depot. Choose a region that itself has crossed the emptiness threshold (i.e
-	// is at least fraction "f" empty.) Such a region will be marked "suitable" on the recirculation list.
-	region_trailer_t *node = tiny_mag_ptr->firstNode;
-
-	while (node && !node->recirc_suitable) {
-		node = node->next;
-	}
-
-	if (NULL == node) {
-#if DEBUG_MALLOC
-		malloc_printf("*** tiny_free_do_recirc_to_depot end of list\n");
-#endif
-		return TRUE; // Caller must SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-	}
-
-	region_t sparse_region = TINY_REGION_FOR_PTR(node);
-
-	// Deal with unclaimed memory -- mag_bytes_free_at_end or mag_bytes_free_at_start
-	if (sparse_region == tiny_mag_ptr->mag_last_region && (tiny_mag_ptr->mag_bytes_free_at_end || tiny_mag_ptr->mag_bytes_free_at_start)) {
-		tiny_finalize_region(szone, tiny_mag_ptr);
-	}
-
-	// disconnect "suitable" node from magazine
-	recirc_list_extract(szone, tiny_mag_ptr, node);
-
-	// Iterate the region pulling its free entries off its (locked) magazine's free list
-	int objects_in_use = tiny_free_detach_region(szone, tiny_mag_ptr, sparse_region);
-	magazine_t *depot_ptr = &(szone->tiny_magazines[DEPOT_MAGAZINE_INDEX]);
-
-	// hand over the region to the (locked) Depot
-	SZONE_MAGAZINE_PTR_LOCK(szone,depot_ptr);
-	// this will cause tiny_free_list_add_ptr called by tiny_free_reattach_region to use
-	// the depot as its target magazine, rather than magazine formerly associated with sparse_region
-	MAGAZINE_INDEX_FOR_TINY_REGION(sparse_region) = DEPOT_MAGAZINE_INDEX;
-	node->pinned_to_depot = 0;
-
-	// Iterate the region putting its free entries on Depot's free list
-	size_t bytes_inplay = tiny_free_reattach_region(szone, depot_ptr, sparse_region);
-
-	tiny_mag_ptr->mag_num_bytes_in_objects -= bytes_inplay;
-	tiny_mag_ptr->num_bytes_in_magazine -= TINY_REGION_PAYLOAD_BYTES;
-	tiny_mag_ptr->mag_num_objects -= objects_in_use;
-
-	SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr); // Unlock the originating magazine
-
-	depot_ptr->mag_num_bytes_in_objects += bytes_inplay;
-	depot_ptr->num_bytes_in_magazine += TINY_REGION_PAYLOAD_BYTES;
-	depot_ptr->mag_num_objects += objects_in_use;
-
-	// connect to Depot as last node
-	recirc_list_splice_last(szone, depot_ptr, node);
-
-	MAGMALLOC_RECIRCREGION((void *)szone, (int)mag_index, (void *)sparse_region, TINY_REGION_SIZE,
-						   (int)BYTES_USED_FOR_TINY_REGION(sparse_region));  // DTrace USDT Probe
-
-	// Mark free'd dirty pages with MADV_FREE to reduce memory pressure
-	tiny_free_scan_madvise_free(szone, depot_ptr, sparse_region);
-
-	// If the region is entirely empty vm_deallocate() it outside the depot lock
-	region_t r_dealloc = tiny_free_try_depot_unmap_no_lock(szone, depot_ptr, node);
-	SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-	if (r_dealloc)
-		deallocate_pages(szone, r_dealloc, TINY_REGION_SIZE, 0);
-	return FALSE; // Caller need not unlock the originating magazine
-}
-
-static region_t
-tiny_find_msize_region(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	free_list_t		*ptr;
-	grain_t		slot = msize - 1;
-	free_list_t		**free_list = tiny_mag_ptr->mag_free_list;
-	free_list_t		**the_slot = free_list + slot;
-	free_list_t		**limit;
-#if defined(__LP64__)
-	uint64_t		bitmap;
-#else
-	uint32_t		bitmap;
-#endif
-	// Assumes we've locked the magazine
-	CHECK_MAGAZINE_PTR_LOCKED(szone, tiny_mag_ptr, __PRETTY_FUNCTION__);
-
-	// Look for an exact match by checking the freelist for this msize.
-	ptr = *the_slot;
-	if (ptr)
-		return TINY_REGION_FOR_PTR(ptr);
-
-	// Mask off the bits representing slots holding free blocks smaller than the
-	// size we need.  If there are no larger free blocks, try allocating from
-	// the free space at the end of the tiny region.
-#if defined(__LP64__)
-	bitmap = ((uint64_t *)(tiny_mag_ptr->mag_bitmap))[0] & ~ ((1ULL << slot) - 1);
-#else
-	bitmap = tiny_mag_ptr->mag_bitmap[0] & ~ ((1 << slot) - 1);
-#endif
-	if (!bitmap)
-		return NULL;
-
-	slot = BITMAPV_CTZ(bitmap);
-	limit = free_list + NUM_TINY_SLOTS - 1;
-	free_list += slot;
-
-	if (free_list < limit) {
-		ptr = *free_list;
-		if (ptr)
-			return TINY_REGION_FOR_PTR(ptr);
-		else {
-			/* Shouldn't happen. Fall through to look at last slot. */
-#if DEBUG_MALLOC
-			malloc_printf("in tiny_find_msize_region(), mag_bitmap out of sync, slot=%d\n",slot);
-#endif
-		}
-	}
-
-	// We are now looking at the last slot, which contains blocks equal to, or
-	// due to coalescing of free blocks, larger than (NUM_TINY_SLOTS - 1) * tiny quantum size.
-	ptr = *limit;
-	if (ptr)
-		return TINY_REGION_FOR_PTR(ptr);
-
-	return NULL;
-}
-
-static boolean_t
-tiny_get_region_from_depot(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	magazine_t *depot_ptr = &(szone->tiny_magazines[DEPOT_MAGAZINE_INDEX]);
-
-	/* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
-	if (szone->num_tiny_magazines == 1) // Uniprocessor, single magazine, so no recirculation necessary
-		return 0;
-
-#if DEBUG_MALLOC
-	if (DEPOT_MAGAZINE_INDEX == mag_index) {
-		szone_error(szone, 1, "tiny_get_region_from_depot called for magazine index -1", NULL, NULL);
-		return 0;
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(szone,depot_ptr);
-
-	// Appropriate a Depot'd region that can satisfy requested msize.
-	region_trailer_t *node;
-	region_t sparse_region;
-
-	while (1) {
-		sparse_region = tiny_find_msize_region(szone, depot_ptr, DEPOT_MAGAZINE_INDEX, msize);
-		if (NULL == sparse_region) { // Depot empty?
-			SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-			return 0;
-		}
-
-		node = REGION_TRAILER_FOR_TINY_REGION(sparse_region);
-		if (0 >= node->pinned_to_depot)
-			break;
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-		yield();
-		SZONE_MAGAZINE_PTR_LOCK(szone,depot_ptr);
-	}
-
-	// disconnect node from Depot
-	recirc_list_extract(szone, depot_ptr, node);
-
-	// Iterate the region pulling its free entries off the (locked) Depot's free list
-	int objects_in_use = tiny_free_detach_region(szone, depot_ptr, sparse_region);
-
-	// Transfer ownership of the region
-	MAGAZINE_INDEX_FOR_TINY_REGION(sparse_region) = mag_index;
-	node->pinned_to_depot = 0;
-
-	// Iterate the region putting its free entries on its new (locked) magazine's free list
-	size_t bytes_inplay = tiny_free_reattach_region(szone, tiny_mag_ptr, sparse_region);
-
-	depot_ptr->mag_num_bytes_in_objects -= bytes_inplay;
-	depot_ptr->num_bytes_in_magazine -= TINY_REGION_PAYLOAD_BYTES;
-	depot_ptr->mag_num_objects -= objects_in_use;
-
-	tiny_mag_ptr->mag_num_bytes_in_objects += bytes_inplay;
-	tiny_mag_ptr->num_bytes_in_magazine += TINY_REGION_PAYLOAD_BYTES;
-	tiny_mag_ptr->mag_num_objects += objects_in_use;
-
-	// connect to magazine as first node
-	recirc_list_splice_first(szone, tiny_mag_ptr, node);
-
-	SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-
-	// madvise() outside the Depot lock
-	(void)madvise_reuse_range(szone, sparse_region, sparse_region, sparse_region+TINY_REGION_PAYLOAD_BYTES);
-
-	MAGMALLOC_DEPOTREGION((void *)szone, (int)mag_index, (void *)sparse_region, TINY_REGION_SIZE,
-						  (int)BYTES_USED_FOR_TINY_REGION(sparse_region)); // DTrace USDT Probe
-
-	return 1;
-}
-
-#define K 1.5 // headroom measured in number of 1Mb regions
-#define DENSITY_THRESHOLD(a) \
-	((a) - ((a) >> 2)) // "Emptiness" f = 0.25, so "Density" is (1 - f)*a. Generally: ((a) - ((a) >> -log2(f)))
-
-static INLINE boolean_t
-tiny_free_no_lock(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, region_t region, void *ptr,
-				  msize_t msize)
-{
-	void	*original_ptr = ptr;
-	size_t	original_size = TINY_BYTES_FOR_MSIZE(msize);
-	void	*next_block = ((unsigned char *)ptr + original_size);
-	msize_t	previous_msize, next_msize;
-	void	*previous;
-	free_list_t	*big_free_block;
-	free_list_t	*after_next_block;
-	free_list_t	*before_next_block;
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in tiny_free_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-	if (!msize) {
-		szone_error(szone, 1, "trying to free tiny block that is too small", ptr,
-					"in tiny_free_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-#endif
-
-	// We try to coalesce this block with the preceeding one
-	previous = tiny_previous_preceding_free(ptr, &previous_msize);
-	if (previous) {
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr) || LOG(szone,previous)) {
-			malloc_printf("in tiny_free_no_lock(), coalesced backwards for %p previous=%p\n", ptr, previous);
-		}
-#endif
-
-		// clear the meta_header since this is no longer the start of a block
-		set_tiny_meta_header_middle(ptr);
-		tiny_free_list_remove_ptr(szone, tiny_mag_ptr, previous, previous_msize);
-		ptr = previous;
-		msize += previous_msize;
-	}
-	// We try to coalesce with the next block
-	if ((next_block < TINY_REGION_END(region)) && tiny_meta_header_is_free(next_block)) {
-		next_msize = get_tiny_free_size(next_block);
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr) || LOG(szone, next_block)) {
-			malloc_printf("in tiny_free_no_lock(), for ptr=%p, msize=%d coalesced forward=%p next_msize=%d\n",
-						  ptr, msize, next_block, next_msize);
-		}
-#endif
-		// If we are coalescing with the next block, and the next block is in
-		// the last slot of the free list, then we optimize this case here to
-		// avoid removing next_block from the slot (NUM_TINY_SLOTS - 1) and then adding ptr back
-		// to slot (NUM_TINY_SLOTS - 1).
-		if (next_msize >= NUM_TINY_SLOTS) {
-			msize += next_msize;
-
-			big_free_block = (free_list_t *)next_block;
-			after_next_block = free_list_unchecksum_ptr(szone, &big_free_block->next);
-			before_next_block = free_list_unchecksum_ptr(szone, &big_free_block->previous);
-
-			if (!before_next_block) {
-				tiny_mag_ptr->mag_free_list[NUM_TINY_SLOTS-1] = ptr;
-			} else {
-				before_next_block->next.u = free_list_checksum_ptr(szone, ptr);
-			}
-
-			if (after_next_block) {
-				after_next_block->previous.u = free_list_checksum_ptr(szone, ptr);
-			}
-
-			// we don't need to checksum these since they are already checksummed
-			((free_list_t *)ptr)->previous = big_free_block->previous;
-			((free_list_t *)ptr)->next = big_free_block->next;
-
-			// clear the meta_header to enable coalescing backwards
-			set_tiny_meta_header_middle(big_free_block);
-			set_tiny_meta_header_free(ptr, msize);
-
-			goto tiny_free_ending;
-		}
-		tiny_free_list_remove_ptr(szone, tiny_mag_ptr, next_block, next_msize);
-		set_tiny_meta_header_middle(next_block); // clear the meta_header to enable coalescing backwards
-		msize += next_msize;
-	}
-
-	// The tiny cache already scribbles free blocks as they go through the
-	// cache whenever msize < TINY_QUANTUM , so we do not need to do it here.
-	if ((szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE) && msize && (msize >= TINY_QUANTUM))
-		memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
-
-	tiny_free_list_add_ptr(szone, tiny_mag_ptr, ptr, msize);
-
-tiny_free_ending:
-
-	tiny_mag_ptr->mag_num_objects--;
-	// we use original_size and not msize to avoid double counting the coalesced blocks
-	tiny_mag_ptr->mag_num_bytes_in_objects -= original_size;
-
-	// Update this region's bytes in use count
-	region_trailer_t *node = REGION_TRAILER_FOR_TINY_REGION(region);
-	size_t bytes_used = node->bytes_used - original_size;
-	node->bytes_used = bytes_used;
-
-#if !TARGET_OS_EMBEDDED // Always madvise for embedded platforms
-	/* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
-	if (szone->num_tiny_magazines == 1) { // Uniprocessor, single magazine, so no recirculation necessary
-		/* NOTHING */
-	} else if (DEPOT_MAGAZINE_INDEX != mag_index) {
-		// Emptiness discriminant
-		if (bytes_used < DENSITY_THRESHOLD(TINY_REGION_PAYLOAD_BYTES)) {
-			/* Region has crossed threshold from density to sparsity. Mark it "suitable" on the
-			 recirculation candidates list. */
-			node->recirc_suitable = TRUE;
-		} else {
-			/* After this free, we've found the region is still dense, so it must have been even more so before
-			 the free. That implies the region is already correctly marked. Do nothing. */
-		}
-
-		// Has the entire magazine crossed the "emptiness threshold"? If so, transfer a region
-		// from this magazine to the Depot. Choose a region that itself has crossed the emptiness threshold (i.e
-		// is at least fraction "f" empty.) Such a region will be marked "suitable" on the recirculation list.
-		size_t a = tiny_mag_ptr->num_bytes_in_magazine; // Total bytes allocated to this magazine
-		size_t u = tiny_mag_ptr->mag_num_bytes_in_objects; // In use (malloc'd) from this magaqzine
-
-		if (a - u > ((3 * TINY_REGION_PAYLOAD_BYTES) / 2) && u < DENSITY_THRESHOLD(a)) {
-			return tiny_free_do_recirc_to_depot(szone, tiny_mag_ptr, mag_index);
-		}
-
-	} else {
-#endif
-		// Freed to Depot. N.B. Lock on tiny_magazines[DEPOT_MAGAZINE_INDEX] is already held
-		// Calcuate the first page in the coalesced block that would be safe to mark MADV_FREE
-		size_t free_header_size = sizeof(free_list_t) + sizeof(msize_t);
-		uintptr_t safe_ptr = (uintptr_t)ptr + free_header_size;
-		uintptr_t round_safe = round_page_quanta(safe_ptr);
-
-		// Calcuate the last page in the coalesced block that would be safe to mark MADV_FREE
-		size_t free_tail_size = sizeof(msize_t);
-		uintptr_t safe_extent = (uintptr_t)ptr + TINY_BYTES_FOR_MSIZE(msize) - free_tail_size;
-		uintptr_t trunc_extent = trunc_page_quanta(safe_extent);
-
-		// The newly freed block may complete a span of bytes that cover a page. Mark it with MADV_FREE.
-		if (round_safe < trunc_extent) { // Coalesced area covers a page (perhaps many)
-			// Extend the freed block by the free region header and tail sizes to include pages
-			// we may have coalesced that no longer host free region tails and headers.
-			// This may extend over in-use ranges, but the MIN/MAX clamping below will fix that up.
-			uintptr_t lo = trunc_page_quanta((uintptr_t)original_ptr - free_tail_size);
-			uintptr_t hi = round_page_quanta((uintptr_t)original_ptr + original_size + free_header_size);
-
-			uintptr_t free_lo = MAX(round_safe, lo);
-			uintptr_t free_hi = MIN(trunc_extent, hi);
-
-			if (free_lo < free_hi) {
-				tiny_free_list_remove_ptr(szone, tiny_mag_ptr, ptr, msize);
-				set_tiny_meta_header_in_use(ptr, msize);
-
-				OSAtomicIncrement32Barrier(&(node->pinned_to_depot));
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				madvise_free_range(szone, region, free_lo, free_hi, &szone->last_tiny_advise);
-				SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-				OSAtomicDecrement32Barrier(&(node->pinned_to_depot));
-
-				set_tiny_meta_header_free(ptr, msize);
-				tiny_free_list_add_ptr(szone, tiny_mag_ptr, ptr, msize);
-			}
-		}
-
-#if !TARGET_OS_EMBEDDED
-		if (0 < bytes_used || 0 < node->pinned_to_depot) {
-			/* Depot'd region is still live. Leave it in place on the Depot's recirculation list
-			 so as to avoid thrashing between the Depot's free list and a magazines's free list
-			 with detach_region/reattach_region */
-		} else {
-			/* Depot'd region is just now empty. Consider return to OS. */
-			region_t r_dealloc = tiny_free_try_depot_unmap_no_lock(szone, tiny_mag_ptr, node);
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-			if (r_dealloc)
-				deallocate_pages(szone, r_dealloc, TINY_REGION_SIZE, 0);
-			return FALSE; // Caller need not unlock
-		}
-	}
-#endif
-
-	return TRUE; // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr)
-}
-
-// Allocates from the last region or a freshly allocated region
-static void *
-tiny_malloc_from_region_no_lock(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index,
-								msize_t msize, void * aligned_address)
-{
-	void	*ptr;
-
-	// Deal with unclaimed memory -- mag_bytes_free_at_end or mag_bytes_free_at_start
-	if (tiny_mag_ptr->mag_bytes_free_at_end || tiny_mag_ptr->mag_bytes_free_at_start)
-		tiny_finalize_region(szone, tiny_mag_ptr);
-
-	// We set the unused bits of the header in the last pair to be all ones, and those of the inuse to zeroes.
-	((tiny_region_t)aligned_address)->pairs[CEIL_NUM_TINY_BLOCKS_WORDS-1].header =
-	(NUM_TINY_BLOCKS & 31) ? (0xFFFFFFFFU << (NUM_TINY_BLOCKS & 31)) : 0;
-	((tiny_region_t)aligned_address)->pairs[CEIL_NUM_TINY_BLOCKS_WORDS-1].inuse = 0;
-
-	// Here find the only place in tinyland that (infrequently) takes the tiny_regions_lock.
-	// Only one thread at a time should be permitted to assess the density of the hash
-	// ring and adjust if needed.
-	// Only one thread at a time should be permitted to insert its new region on
-	// the hash ring.
-	// It is safe for all other threads to read the hash ring (hashed_regions) and
-	// the associated sizes (num_regions_allocated and num_tiny_regions).
-
-	_malloc_lock_lock(&szone->tiny_regions_lock);
-
-	// Check to see if the hash ring of tiny regions needs to grow.  Try to
-	// avoid the hash ring becoming too dense.
-	if (szone->tiny_region_generation->num_regions_allocated < (2 * szone->num_tiny_regions)) {
-		region_t *new_regions;
-		size_t new_size;
-		size_t new_shift = szone->tiny_region_generation->num_regions_allocated_shift; // In/Out parameter
-		new_regions = hash_regions_grow_no_lock(szone, szone->tiny_region_generation->hashed_regions,
-												szone->tiny_region_generation->num_regions_allocated,
-												&new_shift,
-												&new_size);
-		// Do not deallocate the current hashed_regions allocation since someone may
-		// be iterating it.  Instead, just leak it.
-
-		// Prepare to advance to the "next generation" of the hash ring.
-		szone->tiny_region_generation->nextgen->hashed_regions = new_regions;
-		szone->tiny_region_generation->nextgen->num_regions_allocated = new_size;
-		szone->tiny_region_generation->nextgen->num_regions_allocated_shift = new_shift;
-
-		// Throw the switch to atomically advance to the next generation.
-		szone->tiny_region_generation = szone->tiny_region_generation->nextgen;
-		// Ensure everyone sees the advance.
-		OSMemoryBarrier();
-	}
-	// Tag the region at "aligned_address" as belonging to us,
-	// and so put it under the protection of the magazine lock we are holding.
-	// Do this before advertising "aligned_address" on the hash ring(!)
-	MAGAZINE_INDEX_FOR_TINY_REGION(aligned_address) = mag_index;
-
-	// Insert the new region into the hash ring, and update malloc statistics
-	hash_region_insert_no_lock(szone->tiny_region_generation->hashed_regions,
-							   szone->tiny_region_generation->num_regions_allocated,
-							   szone->tiny_region_generation->num_regions_allocated_shift,
-							   aligned_address);
-
-	szone->num_tiny_regions++;
-	_malloc_lock_unlock(&szone->tiny_regions_lock);
-
-	tiny_mag_ptr->mag_last_region = aligned_address;
-	BYTES_USED_FOR_TINY_REGION(aligned_address) = TINY_BYTES_FOR_MSIZE(msize);
-#if ASLR_INTERNAL
-	int offset_msize = malloc_entropy[0] & TINY_ENTROPY_MASK;
-#if DEBUG_MALLOC
-	if (getenv("MallocASLRForce")) offset_msize = strtol(getenv("MallocASLRForce"), NULL, 0) & TINY_ENTROPY_MASK;
-	if (getenv("MallocASLRPrint")) malloc_printf("Region: %p offset: %d\n", aligned_address, offset_msize);
-#endif
-#else
-	int offset_msize = 0;
-#endif
-	ptr = (void *)((uintptr_t) aligned_address + TINY_BYTES_FOR_MSIZE(offset_msize));
-	set_tiny_meta_header_in_use(ptr, msize);
-	tiny_mag_ptr->mag_num_objects++;
-	tiny_mag_ptr->mag_num_bytes_in_objects += TINY_BYTES_FOR_MSIZE(msize);
-	tiny_mag_ptr->num_bytes_in_magazine += TINY_REGION_PAYLOAD_BYTES;
-
-	// We put a header on the last block so that it appears in use (for coalescing, etc...)
-	set_tiny_meta_header_in_use_1((void *)((uintptr_t)ptr + TINY_BYTES_FOR_MSIZE(msize)));
-	tiny_mag_ptr->mag_bytes_free_at_end = TINY_BYTES_FOR_MSIZE(NUM_TINY_BLOCKS - msize - offset_msize);
-
-#if ASLR_INTERNAL
-	// Put a header on the previous block for same reason
-	tiny_mag_ptr->mag_bytes_free_at_start = TINY_BYTES_FOR_MSIZE(offset_msize);
-	if (offset_msize) {
-		set_tiny_meta_header_in_use_1((void *)((uintptr_t)ptr - TINY_QUANTUM));
-	}
-#else
-	tiny_mag_ptr->mag_bytes_free_at_start = 0;
-#endif
-
-	// connect to magazine as last node
-	recirc_list_splice_last(szone, tiny_mag_ptr, REGION_TRAILER_FOR_TINY_REGION(aligned_address));
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in tiny_malloc_from_region_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-#endif
-	return ptr;
-}
-
-static INLINE void *
-tiny_try_shrink_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_good_size)
-{
-	msize_t new_msize = TINY_MSIZE_FOR_BYTES(new_good_size);
-	msize_t mshrinkage = TINY_MSIZE_FOR_BYTES(old_size) - new_msize;
-
-	if (mshrinkage) {
-		void *q = (void *)((uintptr_t)ptr + TINY_BYTES_FOR_MSIZE(new_msize));
-		magazine_t *tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines,
-																	REGION_TRAILER_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr)),
-																	MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr)));
-
-		// Mark q as block header and in-use, thus creating two blocks.
-		set_tiny_meta_header_in_use(q, mshrinkage);
-		tiny_mag_ptr->mag_num_objects++;
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone,tiny_mag_ptr);
-		szone_free(szone, q); // avoid inlining free_tiny(szone, q, ...);
-	}
-	return ptr;
-}
-
-static INLINE boolean_t
-tiny_try_realloc_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_size)
-{
-	// returns 1 on success
-	msize_t	index;
-	msize_t	old_msize;
-	unsigned	next_index;
-	void	*next_block;
-	boolean_t	is_free;
-	msize_t	next_msize, coalesced_msize, leftover_msize;
-	void	*leftover;
-
-	index = TINY_INDEX_FOR_PTR(ptr);
-	old_msize = TINY_MSIZE_FOR_BYTES(old_size);
-	next_index = index + old_msize;
-
-	if (next_index >= NUM_TINY_BLOCKS) {
-		return 0;
-	}
-	next_block = (char *)ptr + old_size;
-
-	magazine_t	*tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines,
-																 REGION_TRAILER_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr)),
-																 MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr)));
-
-	if (DEPOT_MAGAZINE_INDEX == MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr)))
-	{
-	    SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-	    return 0;
-	}
-
-	/*
-	 * Look for a free block immediately afterwards.  If it's large enough, we can consume (part of)
-	 * it.
-	 */
-	is_free = tiny_meta_header_is_free(next_block);
-	if (!is_free) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone,tiny_mag_ptr);
-		return 0; // next_block is in use;
-	}
-	next_msize = get_tiny_free_size(next_block);
-	if (old_size + TINY_BYTES_FOR_MSIZE(next_msize) < new_size) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone,tiny_mag_ptr);
-		return 0; // even with next block, not enough
-	}
-	/*
-	 * The following block is big enough; pull it from its freelist and chop off enough to satisfy
-	 * our needs.
-	 */
-	tiny_free_list_remove_ptr(szone, tiny_mag_ptr, next_block, next_msize);
-	set_tiny_meta_header_middle(next_block); // clear the meta_header to enable coalescing backwards
-	coalesced_msize = TINY_MSIZE_FOR_BYTES(new_size - old_size + TINY_QUANTUM - 1);
-	leftover_msize = next_msize - coalesced_msize;
-	if (leftover_msize) {
-		/* there's some left, so put the remainder back */
-		leftover = (void *)((uintptr_t)next_block + TINY_BYTES_FOR_MSIZE(coalesced_msize));
-
-		tiny_free_list_add_ptr(szone, tiny_mag_ptr, leftover, leftover_msize);
-	}
-	set_tiny_meta_header_in_use(ptr, old_msize + coalesced_msize);
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in tiny_try_realloc_in_place(), ptr=%p, msize=%d\n", ptr, old_msize + coalesced_msize);
-	}
-#endif
-	tiny_mag_ptr->mag_num_bytes_in_objects += TINY_BYTES_FOR_MSIZE(coalesced_msize);
-
-	// Update this region's bytes in use count
-	region_trailer_t *node = REGION_TRAILER_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr));
-	size_t bytes_used = node->bytes_used + TINY_BYTES_FOR_MSIZE(coalesced_msize);
-	node->bytes_used = bytes_used;
-
-	// Emptiness discriminant
-	if (bytes_used < DENSITY_THRESHOLD(TINY_REGION_PAYLOAD_BYTES)) {
-		/* After this reallocation the region is still sparse, so it must have been even more so before
-		 the reallocation. That implies the region is already correctly marked. Do nothing. */
-	} else {
-		/* Region has crossed threshold from sparsity to density. Mark it not "suitable" on the
-		 recirculation candidates list. */
-		node->recirc_suitable = FALSE;
-	}
-
-	SZONE_MAGAZINE_PTR_UNLOCK(szone,tiny_mag_ptr);
-	CHECK(szone, __PRETTY_FUNCTION__);
-	return 1;
-}
-
-static boolean_t
-tiny_check_region(szone_t *szone, region_t region)
-{
-	uintptr_t	start, ptr, region_end;
-	boolean_t	prev_free = 0;
-	boolean_t	is_free;
-	msize_t	msize;
-	free_list_t	*free_head;
-	void	*follower, *previous, *next;
-	mag_index_t	mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(region);
-	magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-
-	// Assumes locked
-	CHECK_MAGAZINE_PTR_LOCKED(szone, tiny_mag_ptr, __PRETTY_FUNCTION__);
-
-	/* establish region limits */
-	start = (uintptr_t)TINY_REGION_ADDRESS(region);
-	ptr = start;
-	if (region == tiny_mag_ptr->mag_last_region) {
-		ptr += tiny_mag_ptr->mag_bytes_free_at_start;
-
-		/*
-		 * Check the leading block's integrity here also.
-		 */
-		if (tiny_mag_ptr->mag_bytes_free_at_start) {
-			msize = get_tiny_meta_header((void *)(ptr - TINY_QUANTUM), &is_free);
-			if (is_free || (msize != 1)) {
-				malloc_printf("*** invariant broken for leader block %p - %d %d\n", ptr - TINY_QUANTUM, msize, is_free);
-			}
-		}
-	}
-	region_end = (uintptr_t)TINY_REGION_END(region);
-
-	/*
-	 * The last region may have a trailing chunk which has not been converted into inuse/freelist
-	 * blocks yet.
-	 */
-	if (region == tiny_mag_ptr->mag_last_region)
-		region_end -= tiny_mag_ptr->mag_bytes_free_at_end;
-
-	/*
-	 * Scan blocks within the region.
-	 */
-	while (ptr < region_end) {
-		/*
-		 * If the first block is free, and its size is 65536 (msize = 0) then the entire region is
-		 * free.
-		 */
-		msize = get_tiny_meta_header((void *)ptr, &is_free);
-		if (is_free && !msize && (ptr == start)) {
-			return 1;
-		}
-
-		/*
-		 * If the block's size is 65536 (msize = 0) then since we're not the first entry the size is
-		 * corrupt.
-		 */
-		if (!msize) {
-			malloc_printf("*** invariant broken for tiny block %p this msize=%d - size is too small\n",
-						  ptr, msize);
-			return 0;
-		}
-
-		if (!is_free) {
-			/*
-			 * In use blocks cannot be more than (NUM_TINY_SLOTS - 1) quanta large.
-			 */
-			prev_free = 0;
-			if (msize > (NUM_TINY_SLOTS - 1)) {
-				malloc_printf("*** invariant broken for %p this tiny msize=%d - size is too large\n",
-							  ptr, msize);
-				return 0;
-			}
-			/* move to next block */
-			ptr += TINY_BYTES_FOR_MSIZE(msize);
-		} else {
-#if !RELAXED_INVARIANT_CHECKS
-			/*
-			 * Free blocks must have been coalesced, we cannot have a free block following another
-			 * free block.
-			 */
-			if (prev_free) {
-				malloc_printf("*** invariant broken for free block %p this tiny msize=%d: two free blocks in a row\n",
-							  ptr, msize);
-				return 0;
-			}
-#endif // RELAXED_INVARIANT_CHECKS
-			prev_free = 1;
-			/*
-			 * Check the integrity of this block's entry in its freelist.
-			 */
-			free_head = (free_list_t *)ptr;
-			previous = free_list_unchecksum_ptr(szone, &free_head->previous);
-			next = free_list_unchecksum_ptr(szone, &free_head->next);
-			if (previous && !tiny_meta_header_is_free(previous)) {
-				malloc_printf("*** invariant broken for %p (previous %p is not a free pointer)\n",
-							  ptr, previous);
-				return 0;
-			}
-			if (next && !tiny_meta_header_is_free(next)) {
-				malloc_printf("*** invariant broken for %p (next in free list %p is not a free pointer)\n",
-							  ptr, next);
-				return 0;
-			}
-			/*
-			 * Check the free block's trailing size value.
-			 */
-			follower = FOLLOWING_TINY_PTR(ptr, msize);
-			if (((uintptr_t)follower != region_end) && (get_tiny_previous_free_msize(follower) != msize)) {
-				malloc_printf("*** invariant broken for tiny free %p followed by %p in region [%p-%p] "
-							  "(end marker incorrect) should be %d; in fact %d\n",
-							  ptr, follower, TINY_REGION_ADDRESS(region), region_end, msize, get_tiny_previous_free_msize(follower));
-				return 0;
-			}
-			/* move to next block */
-			ptr = (uintptr_t)follower;
-		}
-	}
-	/*
-	 * Ensure that we scanned the entire region
-	 */
-	if (ptr != region_end) {
-		malloc_printf("*** invariant broken for region end %p - %p\n", ptr, region_end);
-		return 0;
-	}
-	/*
-	 * Check the trailing block's integrity.
-	 */
-	if (region == tiny_mag_ptr->mag_last_region) {
-		if (tiny_mag_ptr->mag_bytes_free_at_end) {
-			msize = get_tiny_meta_header((void *)ptr, &is_free);
-			if (is_free || (msize != 1)) {
-				malloc_printf("*** invariant broken for blocker block %p - %d %d\n", ptr, msize, is_free);
-			}
-		}
-	}
-	return 1;
-}
-
-static kern_return_t
-tiny_in_use_enumerator(task_t task, void *context, unsigned type_mask, szone_t *szone,
-					   memory_reader_t reader, vm_range_recorder_t recorder)
-{
-	size_t		num_regions;
-	size_t		index;
-	region_t		*regions;
-	vm_range_t		buffer[MAX_RECORDER_BUFFER];
-	unsigned		count = 0;
-	kern_return_t	err;
-	region_t		region;
-	vm_range_t		range;
-	vm_range_t		admin_range;
-	vm_range_t		ptr_range;
-	unsigned char	*mapped_region;
-	uint32_t		*block_header;
-	uint32_t		*in_use;
-	unsigned		block_index;
-	unsigned		block_limit;
-	boolean_t		is_free;
-	msize_t		msize;
-	void		*mapped_ptr;
-	unsigned 		bit;
-	magazine_t          *tiny_mag_base = NULL;
-
-	region_hash_generation_t *trg_ptr;
-	err = reader(task, (vm_address_t)szone->tiny_region_generation, sizeof(region_hash_generation_t), (void **)&trg_ptr);
-	if (err) return err;
-
-	num_regions = trg_ptr->num_regions_allocated;
-	err = reader(task, (vm_address_t)trg_ptr->hashed_regions, sizeof(region_t) * num_regions, (void **)&regions);
-	if (err) return err;
-
-	if (type_mask & MALLOC_PTR_IN_USE_RANGE_TYPE) {
-		// Map in all active magazines. Do this outside the iteration over regions.
-		err = reader(task, (vm_address_t)(szone->tiny_magazines),
-					 szone->num_tiny_magazines*sizeof(magazine_t),(void **)&tiny_mag_base);
-		if (err) return err;
-	}
-
-	for (index = 0; index < num_regions; ++index) {
-		region = regions[index];
-		if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
-			range.address = (vm_address_t)TINY_REGION_ADDRESS(region);
-			range.size = (vm_size_t)TINY_REGION_SIZE;
-			if (type_mask & MALLOC_ADMIN_REGION_RANGE_TYPE) {
-				admin_range.address = range.address + TINY_METADATA_START;
-				admin_range.size = TINY_METADATA_SIZE;
-				recorder(task, context, MALLOC_ADMIN_REGION_RANGE_TYPE, &admin_range, 1);
-			}
-			if (type_mask & (MALLOC_PTR_REGION_RANGE_TYPE | MALLOC_ADMIN_REGION_RANGE_TYPE)) {
-				ptr_range.address = range.address;
-				ptr_range.size = NUM_TINY_BLOCKS * TINY_QUANTUM;
-				recorder(task, context, MALLOC_PTR_REGION_RANGE_TYPE, &ptr_range, 1);
-			}
-			if (type_mask & MALLOC_PTR_IN_USE_RANGE_TYPE) {
-				void 		*mag_last_free;
-				vm_address_t	mag_last_free_ptr = 0;
-				msize_t		mag_last_free_msize = 0;
-
-				err = reader(task, range.address, range.size, (void **)&mapped_region);
-				if (err)
-					return err;
-
-				mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(mapped_region);
-				magazine_t *tiny_mag_ptr = tiny_mag_base + mag_index;
-
-				if (DEPOT_MAGAZINE_INDEX != mag_index) {
-					mag_last_free = tiny_mag_ptr->mag_last_free;
-					if (mag_last_free) {
-						mag_last_free_ptr = (uintptr_t) mag_last_free & ~(TINY_QUANTUM - 1);
-						mag_last_free_msize = (uintptr_t) mag_last_free & (TINY_QUANTUM - 1);
-					}
-				} else {
-					for (mag_index = 0; mag_index < szone->num_tiny_magazines; mag_index++) {
-						if ((void *)range.address == (tiny_mag_base + mag_index)->mag_last_free_rgn) {
-							mag_last_free = (tiny_mag_base + mag_index)->mag_last_free;
-							if (mag_last_free) {
-								mag_last_free_ptr = (uintptr_t) mag_last_free & ~(TINY_QUANTUM - 1);
-								mag_last_free_msize = (uintptr_t) mag_last_free & (TINY_QUANTUM - 1);
-							}
-						}
-					}
-				}
-
-				block_header = (uint32_t *)(mapped_region + TINY_METADATA_START + sizeof(region_trailer_t));
-				in_use = TINY_INUSE_FOR_HEADER(block_header);
-				block_index = 0;
-				block_limit = NUM_TINY_BLOCKS;
-				if (region == tiny_mag_ptr->mag_last_region) {
-					block_index += TINY_MSIZE_FOR_BYTES(tiny_mag_ptr->mag_bytes_free_at_start);
-					block_limit -= TINY_MSIZE_FOR_BYTES(tiny_mag_ptr->mag_bytes_free_at_end);
-				}
-
-				while (block_index < block_limit) {
-					vm_size_t block_offset = TINY_BYTES_FOR_MSIZE(block_index);
-					is_free = !BITARRAY_BIT(in_use, block_index);
-					if (is_free) {
-						mapped_ptr = mapped_region + block_offset;
-
-						// mapped_region, the address at which 'range' in 'task' has been
-						// mapped into our process, is not necessarily aligned to
-						// TINY_BLOCKS_ALIGN.
-						//
-						// Since the code in get_tiny_free_size() assumes the pointer came
-						// from a properly aligned tiny region, and mapped_region is not
-						// necessarily aligned, then do the size calculation directly.
-						// If the next bit is set in the header bitmap, then the size is one
-						// quantum.  Otherwise, read the size field.
-						if (!BITARRAY_BIT(block_header, (block_index+1)))
-							msize = TINY_FREE_SIZE(mapped_ptr);
-						else
-							msize = 1;
-
-					} else if (range.address + block_offset != mag_last_free_ptr) {
-						msize = 1;
-						bit = block_index + 1;
-						while (! BITARRAY_BIT(block_header, bit)) {
-							bit++;
-							msize ++;
-						}
-						buffer[count].address = range.address + block_offset;
-						buffer[count].size = TINY_BYTES_FOR_MSIZE(msize);
-						count++;
-						if (count >= MAX_RECORDER_BUFFER) {
-							recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE, buffer, count);
-							count = 0;
-						}
-					} else {
-						// Block is not free but it matches mag_last_free_ptr so even
-						// though it is not marked free in the bitmap, we treat it as if
-						// it is and move on
-						msize = mag_last_free_msize;
-					}
-
-					if (!msize)
-						return KERN_FAILURE; // Somethings amiss. Avoid looping at this block_index.
-
-					block_index += msize;
-				}
-				if (count) {
-					recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE, buffer, count);
-					count = 0;
-				}
-			}
-		}
-	}
-	return 0;
-}
-
-static void *
-tiny_malloc_from_free_list(szone_t *szone, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	free_list_t		*ptr;
-	msize_t		this_msize;
-	grain_t		slot = msize - 1;
-	free_list_t		**free_list = tiny_mag_ptr->mag_free_list;
-	free_list_t		**the_slot = free_list + slot;
-	free_list_t		*next;
-	free_list_t		**limit;
-#if defined(__LP64__)
-	uint64_t		bitmap;
-#else
-	uint32_t		bitmap;
-#endif
-	msize_t		leftover_msize;
-	free_list_t		*leftover_ptr;
-
-	// Assumes we've locked the region
-	CHECK_MAGAZINE_PTR_LOCKED(szone, tiny_mag_ptr, __PRETTY_FUNCTION__);
-
-	// Look for an exact match by checking the freelist for this msize.
-	//
-	ptr = *the_slot;
-	if (ptr) {
-		next = free_list_unchecksum_ptr(szone, &ptr->next);
-		if (next) {
-			next->previous = ptr->previous;
-		} else {
-			BITMAPV_CLR(tiny_mag_ptr->mag_bitmap, slot);
-		}
-		*the_slot = next;
-		this_msize = msize;
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr)) {
-			malloc_printf("in tiny_malloc_from_free_list(), exact match ptr=%p, this_msize=%d\n", ptr, this_msize);
-		}
-#endif
-		goto return_tiny_alloc;
-	}
-
-	// Mask off the bits representing slots holding free blocks smaller than the
-	// size we need.  If there are no larger free blocks, try allocating from
-	// the free space at the end of the tiny region.
-#if defined(__LP64__)
-	bitmap = ((uint64_t *)(tiny_mag_ptr->mag_bitmap))[0] & ~ ((1ULL << slot) - 1);
-#else
-	bitmap = tiny_mag_ptr->mag_bitmap[0] & ~ ((1 << slot) - 1);
-#endif
-	if (!bitmap)
-		goto try_tiny_malloc_from_end;
-
-	slot = BITMAPV_CTZ(bitmap);
-	limit = free_list + NUM_TINY_SLOTS - 1;
-	free_list += slot;
-
-	if (free_list < limit) {
-		ptr = *free_list;
-		if (ptr) {
-			next = free_list_unchecksum_ptr(szone, &ptr->next);
-			*free_list = next;
-			if (next) {
-				next->previous = ptr->previous;
-			} else {
-				BITMAPV_CLR(tiny_mag_ptr->mag_bitmap, slot);
-			}
-			this_msize = get_tiny_free_size(ptr);
-			goto add_leftover_and_proceed;
-		}
-#if DEBUG_MALLOC
-		malloc_printf("in tiny_malloc_from_free_list(), mag_bitmap out of sync, slot=%d\n",slot);
-#endif
-	}
-
-	// We are now looking at the last slot, which contains blocks equal to, or
-	// due to coalescing of free blocks, larger than (NUM_TINY_SLOTS - 1) * tiny quantum size.
-	// If the last freelist is not empty, and the head contains a block that is
-	// larger than our request, then the remainder is put back on the free list.
-	ptr = *limit;
-	if (ptr) {
-		this_msize = get_tiny_free_size(ptr);
-		next = free_list_unchecksum_ptr(szone, &ptr->next);
-		if (this_msize - msize >= NUM_TINY_SLOTS) {
-			// the leftover will go back to the free list, so we optimize by
-			// modifying the free list rather than a pop and push of the head
-			leftover_msize = this_msize - msize;
-			leftover_ptr = (free_list_t *)((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
-			*limit = leftover_ptr;
-			if (next) {
-				next->previous.u = free_list_checksum_ptr(szone, leftover_ptr);
-			}
-			leftover_ptr->previous = ptr->previous;
-			leftover_ptr->next = ptr->next;
-			set_tiny_meta_header_free(leftover_ptr, leftover_msize);
-#if DEBUG_MALLOC
-			if (LOG(szone,ptr)) {
-				malloc_printf("in tiny_malloc_from_free_list(), last slot ptr=%p, msize=%d this_msize=%d\n",
-							  ptr, msize, this_msize);
-			}
-#endif
-			this_msize = msize;
-			goto return_tiny_alloc;
-		}
-		if (next) {
-			next->previous = ptr->previous;
-		}
-		*limit = next;
-		goto add_leftover_and_proceed;
-		/* NOTREACHED */
-	}
-
-try_tiny_malloc_from_end:
-	// Let's see if we can use tiny_mag_ptr->mag_bytes_free_at_end
-	if (tiny_mag_ptr->mag_bytes_free_at_end >= TINY_BYTES_FOR_MSIZE(msize)) {
-		ptr = (free_list_t *)((uintptr_t)TINY_REGION_END(tiny_mag_ptr->mag_last_region) -
-							  tiny_mag_ptr->mag_bytes_free_at_end);
-		tiny_mag_ptr->mag_bytes_free_at_end -= TINY_BYTES_FOR_MSIZE(msize);
-		if (tiny_mag_ptr->mag_bytes_free_at_end) {
-			// let's add an in use block after ptr to serve as boundary
-			set_tiny_meta_header_in_use_1((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
-		}
-		this_msize = msize;
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr)) {
-			malloc_printf("in tiny_malloc_from_free_list(), from end ptr=%p, msize=%d\n", ptr, msize);
-		}
-#endif
-		goto return_tiny_alloc;
-	}
-#if ASLR_INTERNAL
-	// Try from start if nothing left at end
-	if (tiny_mag_ptr->mag_bytes_free_at_start >= TINY_BYTES_FOR_MSIZE(msize)) {
-		ptr = (free_list_t *)(TINY_REGION_ADDRESS(tiny_mag_ptr->mag_last_region) +
-							  tiny_mag_ptr->mag_bytes_free_at_start - TINY_BYTES_FOR_MSIZE(msize));
-		tiny_mag_ptr->mag_bytes_free_at_start -= TINY_BYTES_FOR_MSIZE(msize);
-		if (tiny_mag_ptr->mag_bytes_free_at_start) {
-			// let's add an in use block before ptr to serve as boundary
-			set_tiny_meta_header_in_use_1((unsigned char *)ptr - TINY_QUANTUM);
-		}
-		this_msize = msize;
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr)) {
-			malloc_printf("in tiny_malloc_from_free_list(), from start ptr=%p, msize=%d\n", ptr, msize);
-		}
-#endif
-		goto return_tiny_alloc;
-	}
-#endif
-	return NULL;
-
-add_leftover_and_proceed:
-	if (!this_msize || (this_msize > msize)) {
-		leftover_msize = this_msize - msize;
-		leftover_ptr = (free_list_t *)((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
-#if DEBUG_MALLOC
-		if (LOG(szone,ptr)) {
-			malloc_printf("in tiny_malloc_from_free_list(), adding leftover ptr=%p, this_msize=%d\n", ptr, this_msize);
-		}
-#endif
-		tiny_free_list_add_ptr(szone, tiny_mag_ptr, leftover_ptr, leftover_msize);
-		this_msize = msize;
-	}
-
-return_tiny_alloc:
-	tiny_mag_ptr->mag_num_objects++;
-	tiny_mag_ptr->mag_num_bytes_in_objects += TINY_BYTES_FOR_MSIZE(this_msize);
-
-	// Update this region's bytes in use count
-	region_trailer_t *node = REGION_TRAILER_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr));
-	size_t bytes_used = node->bytes_used + TINY_BYTES_FOR_MSIZE(this_msize);
-	node->bytes_used = bytes_used;
-
-	// Emptiness discriminant
-	if (bytes_used < DENSITY_THRESHOLD(TINY_REGION_PAYLOAD_BYTES)) {
-		/* After this allocation the region is still sparse, so it must have been even more so before
-		 the allocation. That implies the region is already correctly marked. Do nothing. */
-	} else {
-		/* Region has crossed threshold from sparsity to density. Mark it not "suitable" on the
-		 recirculation candidates list. */
-		node->recirc_suitable = FALSE;
-	}
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in tiny_malloc_from_free_list(), ptr=%p, this_msize=%d, msize=%d\n", ptr, this_msize, msize);
-	}
-#endif
-	if (this_msize > 1)
-		set_tiny_meta_header_in_use(ptr, this_msize);
-	else
-		set_tiny_meta_header_in_use_1(ptr);
-	return ptr;
-}
-#undef DENSITY_THRESHOLD
-#undef K
-
-static INLINE void *
-tiny_malloc_should_clear(szone_t *szone, msize_t msize, boolean_t cleared_requested)
-{
-	void	*ptr;
-	mag_index_t	mag_index = mag_get_thread_index(szone);
-	magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-
-#if DEBUG_MALLOC
-	if (DEPOT_MAGAZINE_INDEX == mag_index) {
-		szone_error(szone, 1, "malloc called for magazine index -1", NULL, NULL);
-		return(NULL);
-	}
-
-	if (!msize) {
-		szone_error(szone, 1, "invariant broken (!msize) in allocation (region)", NULL, NULL);
-		return(NULL);
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-
-#if TINY_CACHE
-	ptr = tiny_mag_ptr->mag_last_free;
-
-	if ((((uintptr_t)ptr) & (TINY_QUANTUM - 1)) == msize) {
-		// we have a winner
-		tiny_mag_ptr->mag_last_free = NULL;
-		tiny_mag_ptr->mag_last_free_rgn = NULL;
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-		CHECK(szone, __PRETTY_FUNCTION__);
-		ptr = (void *)((uintptr_t)ptr & ~ (TINY_QUANTUM - 1));
-		if (cleared_requested) {
-			memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
-		}
-#if DEBUG_MALLOC
-		if (LOG(szone,ptr)) {
-			malloc_printf("in tiny_malloc_should_clear(), tiny cache ptr=%p, msize=%d\n", ptr, msize);
-		}
-#endif
-		return ptr;
-	}
-#endif /* TINY_CACHE */
-
-	while (1) {
-		ptr = tiny_malloc_from_free_list(szone, tiny_mag_ptr, mag_index, msize);
-		if (ptr) {
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-			CHECK(szone, __PRETTY_FUNCTION__);
-			if (cleared_requested) {
-				memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
-			}
-			return ptr;
-		}
-
-		if (tiny_get_region_from_depot(szone, tiny_mag_ptr, mag_index, msize)) {
-			ptr = tiny_malloc_from_free_list(szone, tiny_mag_ptr, mag_index, msize);
-			if (ptr) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				CHECK(szone, __PRETTY_FUNCTION__);
-				if (cleared_requested) {
-					memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
-				}
-				return ptr;
-			}
-		}
-
-		// The magazine is exhausted. A new region (heap) must be allocated to satisfy this call to malloc().
-		// The allocation, an mmap() system call, will be performed outside the magazine spin locks by the first
-		// thread that suffers the exhaustion. That thread sets "alloc_underway" and enters a critical section.
-		// Threads arriving here later are excluded from the critical section, yield the CPU, and then retry the
-		// allocation. After some time the magazine is resupplied, the original thread leaves with its allocation,
-		// and retry-ing threads succeed in the code just above.
-		if (!tiny_mag_ptr->alloc_underway) {
-			void *fresh_region;
-
-			// time to create a new region (do this outside the magazine lock)
-			tiny_mag_ptr->alloc_underway = TRUE;
-			OSMemoryBarrier();
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-			fresh_region = allocate_pages_securely(szone, TINY_REGION_SIZE, TINY_BLOCKS_ALIGN, VM_MEMORY_MALLOC_TINY);
-			SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-
-			MAGMALLOC_ALLOCREGION((void *)szone, (int)mag_index, fresh_region, TINY_REGION_SIZE); // DTrace USDT Probe
-
-			if (!fresh_region) { // out of memory!
-				tiny_mag_ptr->alloc_underway = FALSE;
-				OSMemoryBarrier();
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				return NULL;
-			}
-
-			ptr = tiny_malloc_from_region_no_lock(szone, tiny_mag_ptr, mag_index, msize, fresh_region);
-
-			// we don't clear because this freshly allocated space is pristine
-			tiny_mag_ptr->alloc_underway = FALSE;
-			OSMemoryBarrier();
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-			CHECK(szone, __PRETTY_FUNCTION__);
-			return ptr;
-		} else {
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-			yield();
-			SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-		}
-	}
-	/* NOTREACHED */
-}
-
-static NOINLINE void
-free_tiny_botch(szone_t *szone, free_list_t *ptr)
-{
-	mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr));
-	magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-	SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-	szone_error(szone, 1, "double free", ptr, NULL);
-}
-
-static INLINE void
-free_tiny(szone_t *szone, void *ptr, region_t tiny_region, size_t known_size)
-{
-	msize_t	msize;
-	boolean_t	is_free;
-	mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(tiny_region);
-	magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-
-	// ptr is known to be in tiny_region
-	if (known_size) {
-		msize = TINY_MSIZE_FOR_BYTES(known_size + TINY_QUANTUM - 1);
-	} else {
-		msize = get_tiny_meta_header(ptr, &is_free);
-		if (is_free) {
-			free_tiny_botch(szone, ptr);
-			return;
-		}
-	}
-#if DEBUG_MALLOC
-	if (!msize) {
-		malloc_printf("*** free_tiny() block in use is too large: %p\n", ptr);
-		return;
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-
-#if TINY_CACHE
-	// Depot does not participate in TINY_CACHE since it can't be directly malloc()'d
-	if (DEPOT_MAGAZINE_INDEX != mag_index) {
-		if (msize < TINY_QUANTUM) { // to see if the bits fit in the last 4 bits
-			void *ptr2 = tiny_mag_ptr->mag_last_free; // Might be NULL
-			region_t rgn2 = tiny_mag_ptr->mag_last_free_rgn;
-
-			/* check that we don't already have this pointer in the cache */
-			if (ptr == (void *)((uintptr_t)ptr2 & ~ (TINY_QUANTUM - 1))) {
-				free_tiny_botch(szone, ptr);
-				return;
-			}
-
-			if ((szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE) && msize)
-				memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
-
-			tiny_mag_ptr->mag_last_free = (void *)(((uintptr_t)ptr) | msize);
-			tiny_mag_ptr->mag_last_free_rgn = tiny_region;
-
-			if (!ptr2) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				CHECK(szone, __PRETTY_FUNCTION__);
-				return;
-			}
-
-			msize = (uintptr_t)ptr2 & (TINY_QUANTUM - 1);
-			ptr = (void *)(((uintptr_t)ptr2) & ~(TINY_QUANTUM - 1));
-			tiny_region = rgn2;
-		}
-	}
-#endif /* TINY_CACHE */
-
-	// Now in the time it took to acquire the lock, the region may have migrated
-	// from one magazine to another. I.e. trailer->mag_index is volatile.
-	// In which case the magazine lock we obtained (namely magazines[mag_index].mag_lock)
-	// is stale. If so, keep on tryin' ...
-	region_trailer_t *trailer = REGION_TRAILER_FOR_TINY_REGION(tiny_region);
-	mag_index_t refreshed_index;
-
-	while (mag_index != (refreshed_index = trailer->mag_index)) { // Note assignment
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-
-		mag_index = refreshed_index;
-		tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-	}
-
-	if (tiny_free_no_lock(szone, tiny_mag_ptr, mag_index, tiny_region, ptr, msize))
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-
-	CHECK(szone, __PRETTY_FUNCTION__);
-}
-
-static void
-print_tiny_free_list(szone_t *szone)
-{
-	free_list_t	*ptr;
-	_SIMPLE_STRING b = _simple_salloc();
-	mag_index_t mag_index;
-
-	if (b) {
-		_simple_sappend(b, "tiny free sizes:\n");
-		for (mag_index = -1; mag_index < szone->num_tiny_magazines; mag_index++) {
-			grain_t	slot = 0;
-			_simple_sprintf(b,"\tMagazine %d: ", mag_index);
-			while (slot < NUM_TINY_SLOTS) {
-				ptr = szone->tiny_magazines[mag_index].mag_free_list[slot];
-				if (ptr) {
-					_simple_sprintf(b, "%s%y[%d]; ", (slot == NUM_TINY_SLOTS-1) ? ">=" : "",
-									(slot+1)*TINY_QUANTUM, free_list_count(szone, ptr));
-				}
-				slot++;
-			}
-			_simple_sappend(b,"\n");
-		}
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-
-static void
-print_tiny_region(boolean_t verbose, region_t region, size_t bytes_at_start, size_t bytes_at_end)
-{
-	unsigned		counts[1024];
-	unsigned		in_use = 0;
-	uintptr_t		start = (uintptr_t)TINY_REGION_ADDRESS(region);
-	uintptr_t		current = start + bytes_at_end;
-	uintptr_t		limit =  (uintptr_t)TINY_REGION_END(region) - bytes_at_end;
-	boolean_t		is_free;
-	msize_t		msize;
-	unsigned		ci;
-	_SIMPLE_STRING	b;
-	uintptr_t		pgTot = 0;
-
-	if (region == HASHRING_REGION_DEALLOCATED) {
-		if ((b = _simple_salloc()) != NULL) {
-			_simple_sprintf(b, "Tiny region [unknown address] was returned to the OS\n");
-			_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-			_simple_sfree(b);
-		}
-		return;
-	}
-
-	memset(counts, 0, sizeof(counts));
-	while (current < limit) {
-		msize = get_tiny_meta_header((void *)current, &is_free);
-		if (is_free & !msize && (current == start)) {
-			// first block is all free
-			uintptr_t pgLo = round_page_quanta(start + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(start + TINY_REGION_SIZE - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				pgTot += (pgHi - pgLo);
-			}
-			break;
-		}
-		if (!msize) {
-			malloc_printf("*** error with %p: msize=%d\n", (void *)current, (unsigned)msize);
-			break;
-		}
-		if (!is_free) {
-			// block in use
-			if (msize > NUM_TINY_SLOTS)
-				malloc_printf("*** error at %p msize for in_use is %d\n", (void *)current, msize);
-			if (msize < 1024)
-				counts[msize]++;
-			in_use++;
-		} else {
-			uintptr_t pgLo = round_page_quanta(current + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(current + TINY_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				pgTot += (pgHi - pgLo);
-			}
-		}
-		current += TINY_BYTES_FOR_MSIZE(msize);
-	}
-	if ((b = _simple_salloc()) != NULL) {
-		_simple_sprintf(b, "Tiny region [%p-%p, %y] \t", (void *)start, TINY_REGION_END(region), (int)TINY_REGION_SIZE);
-		_simple_sprintf(b, "Magazine=%d \t", MAGAZINE_INDEX_FOR_TINY_REGION(region));
-		_simple_sprintf(b, "Allocations in use=%d \t Bytes in use=%ly \t", in_use, BYTES_USED_FOR_TINY_REGION(region));
-		if (bytes_at_end || bytes_at_start)
-			_simple_sprintf(b, "Untouched=%ly ", bytes_at_end + bytes_at_start);
-		if (DEPOT_MAGAZINE_INDEX == MAGAZINE_INDEX_FOR_TINY_REGION(region)) {
-			_simple_sprintf(b, "Advised MADV_FREE=%ly", pgTot);
-		} else {
-			_simple_sprintf(b, "Fragments subject to reclamation=%ly", pgTot);
-		}
-		if (verbose && in_use) {
-			_simple_sappend(b, "\n\tSizes in use: ");
-			for (ci = 0; ci < 1024; ci++)
-				if (counts[ci])
-					_simple_sprintf(b, "%d[%d] ", TINY_BYTES_FOR_MSIZE(ci), counts[ci]);
-		}
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-
-static boolean_t
-tiny_free_list_check(szone_t *szone, grain_t slot)
-{
-	mag_index_t mag_index;
-
-	for (mag_index = -1; mag_index < szone->num_tiny_magazines; mag_index++) {
-		magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-
-		unsigned	count = 0;
-		free_list_t	*ptr = szone->tiny_magazines[mag_index].mag_free_list[slot];
-		boolean_t	is_free;
-		free_list_t	*previous = NULL;
-
-		while (ptr) {
-			is_free = tiny_meta_header_is_free(ptr);
-			if (! is_free) {
-				malloc_printf("*** in-use ptr in free list slot=%d count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				return 0;
-			}
-			if (((uintptr_t)ptr) & (TINY_QUANTUM - 1)) {
-				malloc_printf("*** unaligned ptr in free list slot=%d  count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				return 0;
-			}
-			if (!tiny_region_for_ptr_no_lock(szone, ptr)) {
-				malloc_printf("*** ptr not in szone slot=%d  count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				return 0;
-			}
-			if (free_list_unchecksum_ptr(szone, &ptr->previous) != previous) {
-				malloc_printf("*** previous incorrectly set slot=%d  count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				return 0;
-			}
-			previous = ptr;
-			ptr = free_list_unchecksum_ptr(szone, &ptr->next);
-			count++;
-		}
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-	}
-	return 1;
-}
-
-/*********************	SMALL FREE LIST UTILITIES	************************/
-
-/*
- * Mark a block as free.  Only the first quantum of a block is marked thusly,
- * the remainder are marked "middle".
- */
-static INLINE void
-small_meta_header_set_is_free(msize_t *meta_headers, unsigned index, msize_t msize)
-{
-	meta_headers[index] = msize | SMALL_IS_FREE;
-}
-
-/*
- * Mark a block as in use.  Only the first quantum of a block is marked thusly,
- * the remainder are marked "middle".
- */
-static INLINE void
-small_meta_header_set_in_use(msize_t *meta_headers, msize_t index, msize_t msize)
-{
-	meta_headers[index] = msize;
-}
-
-/*
- * Mark a quantum as being the second or later in a block.
- */
-static INLINE void
-small_meta_header_set_middle(msize_t *meta_headers, msize_t index)
-{
-	meta_headers[index] = 0;
-}
-
-/*
- * Adds an item to the proper free list, and also marks the meta-header of the
- * block properly.
- * Assumes szone has been locked
- */
-static void
-small_free_list_add_ptr(szone_t *szone, magazine_t *small_mag_ptr, void *ptr, msize_t msize)
-{
-	grain_t	slot = (msize <= szone->num_small_slots) ? msize - 1 : szone->num_small_slots - 1;
-	free_list_t	*free_ptr = ptr;
-	free_list_t	*free_head = small_mag_ptr->mag_free_list[slot];
-	void	*follower;
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
-	}
-	if (((uintptr_t)ptr) & (SMALL_QUANTUM - 1)) {
-		szone_error(szone, 1, "small_free_list_add_ptr: Unaligned ptr", ptr, NULL);
-	}
-#endif
-	small_meta_header_set_is_free(SMALL_META_HEADER_FOR_PTR(ptr), SMALL_META_INDEX_FOR_PTR(ptr), msize);
-
-	if (free_head) {
-#if DEBUG_MALLOC
-		if (free_list_unchecksum_ptr(szone, &free_head->previous)) {
-			szone_error(szone, 1, "small_free_list_add_ptr: Internal invariant broken (free_head->previous)", ptr,
-						"ptr=%p slot=%d free_head=%p previous=%p\n", ptr, slot, (void *)free_head, free_head->previous.p);
-		}
-		if (!SMALL_PTR_IS_FREE(free_head)) {
-			szone_error(szone, 1, "small_free_list_add_ptr: Internal invariant broken (free_head is not a free pointer)", ptr,
-						"ptr=%p slot=%d free_head=%p\n", ptr, slot, (void *)free_head);
-		}
-#endif
-		free_head->previous.u = free_list_checksum_ptr(szone, free_ptr);
-	} else {
-		BITMAPN_SET(small_mag_ptr->mag_bitmap, slot);
-	}
-	free_ptr->previous.u = free_list_checksum_ptr(szone, NULL);
-	free_ptr->next.u = free_list_checksum_ptr(szone, free_head);
-
-	small_mag_ptr->mag_free_list[slot] = free_ptr;
-
-	// Store msize at the end of the block denoted by "ptr" (i.e. at a negative offset from "follower")
-	follower = (void *)((uintptr_t)ptr + SMALL_BYTES_FOR_MSIZE(msize));
-	SMALL_PREVIOUS_MSIZE(follower) = msize;
-}
-
-/*
- * Removes the item pointed to by ptr in the proper free list.
- * Assumes szone has been locked
- */
-static void
-small_free_list_remove_ptr(szone_t *szone, magazine_t *small_mag_ptr, void *ptr, msize_t msize)
-{
-	grain_t	slot = (msize <= szone->num_small_slots) ? msize - 1 : szone->num_small_slots - 1;
-	free_list_t	*free_ptr = ptr, *next, *previous;
-
-	next = free_list_unchecksum_ptr(szone, &free_ptr->next);
-	previous = free_list_unchecksum_ptr(szone, &free_ptr->previous);
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("In %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
-	}
-#endif
-
-	if (!previous) {
-		// The block to remove is the head of the free list
-#if DEBUG_MALLOC
-		if (small_mag_ptr->mag_free_list[slot] != ptr) {
-			szone_error(szone, 1, "small_free_list_remove_ptr: Internal invariant broken (small_mag_ptr->mag_free_list[slot])", ptr,
-						"ptr=%p slot=%d msize=%d small_mag_ptr->mag_free_list[slot]=%p\n",
-						ptr, slot, msize, (void *)small_mag_ptr->mag_free_list[slot]);
-			return;
-		}
-#endif
-		small_mag_ptr->mag_free_list[slot] = next;
-		if (!next) BITMAPN_CLR(small_mag_ptr->mag_bitmap, slot);
-	} else {
-		// We know free_ptr is already checksummed, so we don't need to do it
-		// again.
-		previous->next = free_ptr->next;
-	}
-	if (next) {
-		// We know free_ptr is already checksummed, so we don't need to do it
-		// again.
-		next->previous = free_ptr->previous;
-	}
-}
-
-/*
- * small_region_for_ptr_no_lock - Returns the small region containing the pointer,
- * or NULL if not found.
- */
-static INLINE region_t
-small_region_for_ptr_no_lock(szone_t *szone, const void *ptr)
-{
-	rgnhdl_t r = hash_lookup_region_no_lock(szone->small_region_generation->hashed_regions,
-											szone->small_region_generation->num_regions_allocated,
-											szone->small_region_generation->num_regions_allocated_shift,
-											SMALL_REGION_FOR_PTR(ptr));
-	return r ? *r : r;
-}
-
-static void
-small_finalize_region(szone_t *szone, magazine_t *small_mag_ptr) {
-	void      *last_block, *previous_block;
-	msize_t   last_msize, previous_msize, last_index;
-
-	// It is possible that the block prior to the last block in the region has
-	// been free'd, but was not coalesced with the free bytes at the end of the
-	// block, since we treat the bytes at the end of the region as "in use" in
-	// the meta headers. Attempt to coalesce the last block with the previous
-	// block, so we don't violate the "no consecutive free blocks" invariant.
-	//
-	// FIXME: If we could calculate the previous small free size in the same
-	//        manner as tiny_previous_preceding_free, it would eliminate the
-	//        index & previous msize checks, which are a guard against reading
-	//        bogus data out of in-use or written-on-freed memory.
-	//
-	// FIXME: Need to investigate how much work would be required to increase
-	//        'mag_bytes_free_at_end' when freeing the preceding block, rather
-	//        than performing this workaround.
-	//
-	if (small_mag_ptr->mag_bytes_free_at_end) {
-		last_block = SMALL_REGION_END(small_mag_ptr->mag_last_region) - small_mag_ptr->mag_bytes_free_at_end;
-		last_msize = SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end);
-
-		last_index = SMALL_META_INDEX_FOR_PTR(last_block);
-		previous_msize = SMALL_PREVIOUS_MSIZE(last_block);
-
-		if (last_index && (previous_msize <= last_index)) {
-			previous_block = (void *)((uintptr_t)last_block - SMALL_BYTES_FOR_MSIZE(previous_msize));
-			if (*SMALL_METADATA_FOR_PTR(previous_block) == (previous_msize | SMALL_IS_FREE)) {
-				msize_t *meta_headers = SMALL_META_HEADER_FOR_PTR(last_block);
-
-				small_meta_header_set_middle(meta_headers, last_index);
-				small_free_list_remove_ptr(szone, small_mag_ptr, previous_block, previous_msize);
-				last_block = (void *)((uintptr_t)last_block - SMALL_BYTES_FOR_MSIZE(previous_msize));
-				last_msize += previous_msize;
-			}
-		}
-
-		// splice last_block into the free list
-		small_free_list_add_ptr(szone, small_mag_ptr, last_block, last_msize);
-		small_mag_ptr->mag_bytes_free_at_end = 0;
-	}
-
-#if ASLR_INTERNAL
-	if (small_mag_ptr->mag_bytes_free_at_start) {
-		last_block = SMALL_REGION_ADDRESS(small_mag_ptr->mag_last_region);
-		last_msize = SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_start);
-
-		void *next_block = (void *) ((uintptr_t)last_block + small_mag_ptr->mag_bytes_free_at_start);
-		if (SMALL_PTR_IS_FREE(next_block)) {
-			msize_t next_msize = SMALL_PTR_SIZE(next_block);
-
-			small_meta_header_set_middle(SMALL_META_HEADER_FOR_PTR(next_block), SMALL_META_INDEX_FOR_PTR(next_block));
-			small_free_list_remove_ptr(szone, small_mag_ptr, next_block, next_msize);
-			last_msize += next_msize;
-		}
-
-		// splice last_block into the free list
-		small_free_list_add_ptr(szone, small_mag_ptr, last_block, last_msize);
-		small_mag_ptr->mag_bytes_free_at_start = 0;
-	}
-#endif
-
-	// TODO: Will we ever need to coalesce the blocks at the beginning and end when we finalize?
-
-	small_mag_ptr->mag_last_region = NULL;
-}
-
-static int
-small_free_detach_region(szone_t *szone, magazine_t *small_mag_ptr, region_t r) {
-	unsigned char	*ptr = SMALL_REGION_ADDRESS(r);
-	msize_t		*meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
-	uintptr_t		start = (uintptr_t)SMALL_REGION_ADDRESS(r);
-	uintptr_t		current = start;
-	uintptr_t		limit =  (uintptr_t)SMALL_REGION_END(r);
-	int			total_alloc = 0;
-
-	while (current < limit) {
-		unsigned	index = SMALL_META_INDEX_FOR_PTR(current);
-		msize_t		msize_and_free = meta_headers[index];
-		boolean_t	is_free = msize_and_free & SMALL_IS_FREE;
-		msize_t		msize = msize_and_free & ~ SMALL_IS_FREE;
-
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_printf("*** small_free_detach_region error with %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			break;
-		}
-		if (is_free) {
-			small_free_list_remove_ptr(szone, small_mag_ptr, (void *)current, msize);
-		} else {
-			total_alloc++;
-		}
-		current += SMALL_BYTES_FOR_MSIZE(msize);
-	}
-	return total_alloc;
-}
-
-static size_t
-small_free_reattach_region(szone_t *szone, magazine_t *small_mag_ptr, region_t r) {
-	unsigned char	*ptr = SMALL_REGION_ADDRESS(r);
-	msize_t		*meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
-	uintptr_t		start = (uintptr_t)SMALL_REGION_ADDRESS(r);
-	uintptr_t		current = start;
-	uintptr_t		limit =  (uintptr_t)SMALL_REGION_END(r);
-	size_t		total_alloc = 0;
-
-	while (current < limit) {
-		unsigned	index = SMALL_META_INDEX_FOR_PTR(current);
-		msize_t		msize_and_free = meta_headers[index];
-		boolean_t	is_free = msize_and_free & SMALL_IS_FREE;
-		msize_t		msize = msize_and_free & ~ SMALL_IS_FREE;
-
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_printf("*** small_free_reattach_region error with %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			break;
-		}
-		if (is_free) {
-			small_free_list_add_ptr(szone, small_mag_ptr, (void *)current, msize);
-		} else {
-			total_alloc += SMALL_BYTES_FOR_MSIZE(msize);
-		}
-		current += SMALL_BYTES_FOR_MSIZE(msize);
-	}
-	return total_alloc;
-}
-
-typedef struct {
-	uint16_t pnum, size;
-} small_pg_pair_t;
-
-static void NOINLINE /* want private stack frame for automatic array */
-small_free_scan_madvise_free(szone_t *szone, magazine_t *depot_ptr, region_t r) {
-	uintptr_t	start = (uintptr_t)SMALL_REGION_ADDRESS(r);
-	uintptr_t	current = start;
-	uintptr_t	limit =  (uintptr_t)SMALL_REGION_END(r);
-	msize_t	*meta_headers = SMALL_META_HEADER_FOR_PTR(start);
-	small_pg_pair_t advisory[((SMALL_REGION_PAYLOAD_BYTES + vm_page_quanta_size - 1) >> vm_page_quanta_shift) >> 1]; // 4096bytes stack allocated
-	int		advisories = 0;
-
-	// Scan the metadata identifying blocks which span one or more pages. Mark the pages MADV_FREE taking care to preserve free list
-	// management data.
-	while (current < limit) {
-		unsigned	index = SMALL_META_INDEX_FOR_PTR(current);
-		msize_t		msize_and_free = meta_headers[index];
-		boolean_t	is_free = msize_and_free & SMALL_IS_FREE;
-		msize_t		msize = msize_and_free & ~ SMALL_IS_FREE;
-
-		if (is_free && !msize && (current == start)) {
-#if DEBUG_MALLOC
-			// first block is all free
-			malloc_printf("*** small_free_scan_madvise_free first block is all free! %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			uintptr_t pgLo = round_page_quanta(start + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(start + SMALL_REGION_SIZE - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				advisory[advisories].pnum = (pgLo - start) >> vm_page_quanta_shift;
-				advisory[advisories].size = (pgHi - pgLo) >> vm_page_quanta_shift;
-				advisories++;
-			}
-			break;
-		}
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_printf("*** small_free_scan_madvise_free error with %p: msize=%d is_free =%d\n",
-						  (void *)current, msize, is_free);
-#endif
-			break;
-		}
-		if (is_free) {
-			uintptr_t pgLo = round_page_quanta(current + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(current + SMALL_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				advisory[advisories].pnum = (pgLo - start) >> vm_page_quanta_shift;
-				advisory[advisories].size = (pgHi - pgLo) >> vm_page_quanta_shift;
-				advisories++;
-			}
-		}
-		current += SMALL_BYTES_FOR_MSIZE(msize);
-	}
-
-	if (advisories > 0) {
-		int i;
-
-		OSAtomicIncrement32Barrier(&(REGION_TRAILER_FOR_SMALL_REGION(r)->pinned_to_depot));
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, depot_ptr);
-		for (i = 0; i < advisories; ++i) {
-			uintptr_t addr = (advisory[i].pnum << vm_page_quanta_shift) + start;
-			size_t size = advisory[i].size << vm_page_quanta_shift;
-
-			madvise_free_range(szone, r, addr, addr + size, NULL);
-		}
-		SZONE_MAGAZINE_PTR_LOCK(szone, depot_ptr);
-		OSAtomicDecrement32Barrier(&(REGION_TRAILER_FOR_SMALL_REGION(r)->pinned_to_depot));
-	}
-}
-
-static region_t
-small_free_try_depot_unmap_no_lock(szone_t *szone, magazine_t *depot_ptr, region_trailer_t *node)
-{
-	if (0 < node->bytes_used ||
-		0 < node->pinned_to_depot ||
-		depot_ptr->recirculation_entries < (szone->num_small_magazines * 2)) {
-		return NULL;
-	}
-
-	// disconnect first node from Depot
-	recirc_list_extract(szone, depot_ptr, node);
-
-	// Iterate the region pulling its free entries off the (locked) Depot's free list
-	region_t sparse_region = SMALL_REGION_FOR_PTR(node);
-	int objects_in_use = small_free_detach_region(szone, depot_ptr, sparse_region);
-
-	if (0 == objects_in_use) {
-		// Invalidate the hash table entry for this region with HASHRING_REGION_DEALLOCATED.
-		// Using HASHRING_REGION_DEALLOCATED preserves the collision chain, using HASHRING_OPEN_ENTRY (0) would not.
-		rgnhdl_t pSlot = hash_lookup_region_no_lock(szone->small_region_generation->hashed_regions,
-													szone->small_region_generation->num_regions_allocated,
-													szone->small_region_generation->num_regions_allocated_shift, sparse_region);
-		if (NULL == pSlot) {
-			szone_error(szone, 1, "small_free_try_depot_unmap_no_lock hash lookup failed:", NULL, "%p\n", sparse_region);
-			return NULL;
-		}
-		*pSlot = HASHRING_REGION_DEALLOCATED;
-		depot_ptr->num_bytes_in_magazine -= SMALL_REGION_PAYLOAD_BYTES;
-		__sync_fetch_and_add( &(szone->num_small_regions_dealloc), 1); // Atomically increment num_small_regions_dealloc
-
-		// Caller will transfer ownership of the region back to the OS with no locks held
-		MAGMALLOC_DEALLOCREGION((void *)szone, (void *)sparse_region, SMALL_REGION_SIZE); // DTrace USDT Probe
-		return sparse_region;
-
-	} else {
-		szone_error(szone, 1, "small_free_try_depot_unmap_no_lock objects_in_use not zero:", NULL, "%d\n", objects_in_use);
-		return NULL;
-	}
-}
-
-static boolean_t
-small_free_do_recirc_to_depot(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index)
-{
-	// The entire magazine crossed the "emptiness threshold". Transfer a region
-	// from this magazine to the Depot. Choose a region that itself has crossed the emptiness threshold (i.e
-	// is at least fraction "f" empty.) Such a region will be marked "suitable" on the recirculation list.
-	region_trailer_t *node = small_mag_ptr->firstNode;
-
-	while (node && !node->recirc_suitable) {
-		node = node->next;
-	}
-
-	if (NULL == node) {
-#if DEBUG_MALLOC
-		malloc_printf("*** small_free_do_recirc_to_depot end of list\n");
-#endif
-		return TRUE; // Caller must SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-	}
-
-	region_t sparse_region = SMALL_REGION_FOR_PTR(node);
-
-	// Deal with unclaimed memory -- mag_bytes_free_at_end or mag_bytes_free_at start
-	if (sparse_region == small_mag_ptr->mag_last_region && (small_mag_ptr->mag_bytes_free_at_end || small_mag_ptr->mag_bytes_free_at_start)) {
-		small_finalize_region(szone, small_mag_ptr);
-	}
-
-	// disconnect "suitable" node from magazine
-	recirc_list_extract(szone, small_mag_ptr, node);
-
-	// Iterate the region pulling its free entries off its (locked) magazine's free list
-	int objects_in_use = small_free_detach_region(szone, small_mag_ptr, sparse_region);
-	magazine_t *depot_ptr = &(szone->small_magazines[DEPOT_MAGAZINE_INDEX]);
-
-	// hand over the region to the (locked) Depot
-	SZONE_MAGAZINE_PTR_LOCK(szone,depot_ptr);
-	// this will cause small_free_list_add_ptr called by small_free_reattach_region to use
-	// the depot as its target magazine, rather than magazine formerly associated with sparse_region
-	MAGAZINE_INDEX_FOR_SMALL_REGION(sparse_region) = DEPOT_MAGAZINE_INDEX;
-	node->pinned_to_depot = 0;
-
-	// Iterate the region putting its free entries on Depot's free list
-	size_t bytes_inplay = small_free_reattach_region(szone, depot_ptr, sparse_region);
-
-	small_mag_ptr->mag_num_bytes_in_objects -= bytes_inplay;
-	small_mag_ptr->num_bytes_in_magazine -= SMALL_REGION_PAYLOAD_BYTES;
-	small_mag_ptr->mag_num_objects -= objects_in_use;
-
-	SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr); // Unlock the originating magazine
-
-	depot_ptr->mag_num_bytes_in_objects += bytes_inplay;
-	depot_ptr->num_bytes_in_magazine += SMALL_REGION_PAYLOAD_BYTES;
-	depot_ptr->mag_num_objects += objects_in_use;
-
-	// connect to Depot as last node
-	recirc_list_splice_last(szone, depot_ptr, node);
-
-	MAGMALLOC_RECIRCREGION((void *)szone, (int)mag_index, (void *)sparse_region, SMALL_REGION_SIZE,
-						   (int)BYTES_USED_FOR_SMALL_REGION(sparse_region)); // DTrace USDT Probe
-
-	// Mark free'd dirty pages with MADV_FREE to reduce memory pressure
-	small_free_scan_madvise_free(szone, depot_ptr, sparse_region);
-
-	// If the region is entirely empty vm_deallocate() it outside the depot lock
-	region_t r_dealloc = small_free_try_depot_unmap_no_lock(szone, depot_ptr, node);
-	SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-	if (r_dealloc)
-		deallocate_pages(szone, r_dealloc, SMALL_REGION_SIZE, 0);
-	return FALSE; // Caller need not unlock the originating magazine
-}
-
-static region_t
-small_find_msize_region(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	free_list_t		*ptr;
-	grain_t		slot = (msize <= szone->num_small_slots) ? msize - 1 : szone->num_small_slots - 1;
-	free_list_t		**free_list = small_mag_ptr->mag_free_list;
-	free_list_t		**the_slot = free_list + slot;
-	free_list_t		**limit;
-	unsigned		bitmap;
-
-	// Assumes we've locked the magazine
-	CHECK_MAGAZINE_PTR_LOCKED(szone, small_mag_ptr, __PRETTY_FUNCTION__);
-
-	// Look for an exact match by checking the freelist for this msize.
-	ptr = *the_slot;
-	if (ptr)
-		return SMALL_REGION_FOR_PTR(ptr);
-
-	// Mask off the bits representing slots holding free blocks smaller than
-	// the size we need.
-	if (szone->is_largemem) {
-		// BITMAPN_CTZ implementation
-		unsigned idx = slot >> 5;
-		bitmap = 0;
-		unsigned mask = ~ ((1 << (slot & 31)) - 1);
-		for ( ; idx < SMALL_BITMAP_WORDS; ++idx ) {
-			bitmap = small_mag_ptr->mag_bitmap[idx] & mask;
-			if (bitmap != 0)
-				break;
-			mask = ~0U;
-		}
-		// Check for fallthrough: No bits set in bitmap
-		if ((bitmap == 0) && (idx == SMALL_BITMAP_WORDS))
-			return NULL;
-
-		// Start looking at the first set bit, plus 32 bits for every word of
-		// zeroes or entries that were too small.
-		slot = BITMAP32_CTZ((&bitmap)) + (idx * 32);
-	} else {
-		bitmap = small_mag_ptr->mag_bitmap[0] & ~ ((1 << slot) - 1);
-		if (!bitmap)
-			return NULL;
-
-		slot = BITMAP32_CTZ((&bitmap));
-	}
-	limit = free_list + szone->num_small_slots - 1;
-	free_list += slot;
-
-	if (free_list < limit) {
-		ptr = *free_list;
-		if (ptr)
-			return SMALL_REGION_FOR_PTR(ptr);
-		else {
-			/* Shouldn't happen. Fall through to look at last slot. */
-#if DEBUG_MALLOC
-			malloc_printf("in small_malloc_from_free_list(), mag_bitmap out of sync, slot=%d\n",slot);
-#endif
-		}
-	}
-
-	// We are now looking at the last slot, which contains blocks equal to, or
-	// due to coalescing of free blocks, larger than (num_small_slots - 1) * (small quantum size).
-	ptr = *limit;
-	if (ptr)
-		return SMALL_REGION_FOR_PTR(ptr);
-
-	return NULL;
-}
-
-static boolean_t
-small_get_region_from_depot(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	magazine_t *depot_ptr = &(szone->small_magazines[DEPOT_MAGAZINE_INDEX]);
-
-	/* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
-	if (szone->num_small_magazines == 1) // Uniprocessor, single magazine, so no recirculation necessary
-		return 0;
-
-#if DEBUG_MALLOC
-	if (DEPOT_MAGAZINE_INDEX == mag_index) {
-		szone_error(szone, 1, "small_get_region_from_depot called for magazine index -1", NULL, NULL);
-		return 0;
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(szone,depot_ptr);
-
-	// Appropriate a Depot'd region that can satisfy requested msize.
-	region_trailer_t *node;
-	region_t sparse_region;
-
-	while (1) {
-		sparse_region = small_find_msize_region(szone, depot_ptr, DEPOT_MAGAZINE_INDEX, msize);
-		if (NULL == sparse_region) { // Depot empty?
-			SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-			return 0;
-		}
-
-		node = REGION_TRAILER_FOR_SMALL_REGION(sparse_region);
-		if (0 >= node->pinned_to_depot)
-			break;
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-		yield();
-		SZONE_MAGAZINE_PTR_LOCK(szone,depot_ptr);
-	}
-
-	// disconnect node from Depot
-	recirc_list_extract(szone, depot_ptr, node);
-
-	// Iterate the region pulling its free entries off the (locked) Depot's free list
-	int objects_in_use = small_free_detach_region(szone, depot_ptr, sparse_region);
-
-	// Transfer ownership of the region
-	MAGAZINE_INDEX_FOR_SMALL_REGION(sparse_region) = mag_index;
-	node->pinned_to_depot = 0;
-
-	// Iterate the region putting its free entries on its new (locked) magazine's free list
-	size_t bytes_inplay = small_free_reattach_region(szone, small_mag_ptr, sparse_region);
-
-	depot_ptr->mag_num_bytes_in_objects -= bytes_inplay;
-	depot_ptr->num_bytes_in_magazine -= SMALL_REGION_PAYLOAD_BYTES;
-	depot_ptr->mag_num_objects -= objects_in_use;
-
-	small_mag_ptr->mag_num_bytes_in_objects += bytes_inplay;
-	small_mag_ptr->num_bytes_in_magazine += SMALL_REGION_PAYLOAD_BYTES;
-	small_mag_ptr->mag_num_objects += objects_in_use;
-
-	// connect to magazine as first node
-	recirc_list_splice_first(szone, small_mag_ptr, node);
-
-	SZONE_MAGAZINE_PTR_UNLOCK(szone,depot_ptr);
-
-	// madvise() outside the Depot lock
-	(void)madvise_reuse_range(szone, sparse_region, sparse_region, sparse_region+SMALL_REGION_PAYLOAD_BYTES);
-
-	MAGMALLOC_DEPOTREGION((void *)szone, (int)mag_index, (void *)sparse_region, SMALL_REGION_SIZE,
-						  (int)BYTES_USED_FOR_SMALL_REGION(sparse_region)); // DTrace USDT Probe
-
-	return 1;
-}
-
-#define K 1.5 // headroom measured in number of 8Mb regions
-#define DENSITY_THRESHOLD(a) \
-	((a) - ((a) >> 2)) // "Emptiness" f = 0.25, so "Density" is (1 - f)*a. Generally: ((a) - ((a) >> -log2(f)))
-
-static INLINE boolean_t
-small_free_no_lock(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, region_t region, void *ptr, msize_t msize)
-{
-	msize_t		*meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
-	unsigned		index = SMALL_META_INDEX_FOR_PTR(ptr);
-	void		*original_ptr = ptr;
-	size_t		original_size = SMALL_BYTES_FOR_MSIZE(msize);
-	unsigned char	*next_block = ((unsigned char *)ptr + original_size);
-	msize_t		next_index = index + msize;
-	msize_t		previous_msize, next_msize;
-	void		*previous;
-
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in small_free_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-	if (!msize) {
-		szone_error(szone, 1, "trying to free small block that is too small", ptr,
-					"in small_free_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-#endif
-
-	// We try to coalesce this block with the preceeding one
-	if (index && (SMALL_PREVIOUS_MSIZE(ptr) <= index)) {
-		previous_msize = SMALL_PREVIOUS_MSIZE(ptr);
-		if (meta_headers[index - previous_msize] == (previous_msize | SMALL_IS_FREE)) {
-			previous = (void *)((uintptr_t)ptr - SMALL_BYTES_FOR_MSIZE(previous_msize));
-			// previous is really to be coalesced
-#if DEBUG_MALLOC
-			if (LOG(szone, ptr) || LOG(szone,previous)) {
-				malloc_printf("in small_free_no_lock(), coalesced backwards for %p previous=%p\n", ptr, previous);
-			}
-#endif
-			small_free_list_remove_ptr(szone, small_mag_ptr, previous, previous_msize);
-			small_meta_header_set_middle(meta_headers, index);
-			ptr = previous;
-			msize += previous_msize;
-			index -= previous_msize;
-		}
-	}
-	// We try to coalesce with the next block
-	if ((next_block < SMALL_REGION_END(region)) && (meta_headers[next_index] & SMALL_IS_FREE)) {
-		// next block is free, we coalesce
-		next_msize = meta_headers[next_index] & ~ SMALL_IS_FREE;
-#if DEBUG_MALLOC
-		if (LOG(szone,ptr))
-			malloc_printf("In small_free_no_lock(), for ptr=%p, msize=%d coalesced next block=%p next_msize=%d\n",
-						  ptr, msize, next_block, next_msize);
-#endif
-		small_free_list_remove_ptr(szone, small_mag_ptr, next_block, next_msize);
-		small_meta_header_set_middle(meta_headers, next_index);
-		msize += next_msize;
-	}
-	if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE) {
-		if (!msize) {
-			szone_error(szone, 1, "incorrect size information - block header was damaged", ptr, NULL);
-		} else {
-			memset(ptr, SCRABBLE_BYTE, SMALL_BYTES_FOR_MSIZE(msize));
-		}
-	}
-	small_free_list_add_ptr(szone, small_mag_ptr, ptr, msize);
-	small_mag_ptr->mag_num_objects--;
-	// we use original_size and not msize to avoid double counting the coalesced blocks
-	small_mag_ptr->mag_num_bytes_in_objects -= original_size;
-
-	// Update this region's bytes in use count
-	region_trailer_t *node = REGION_TRAILER_FOR_SMALL_REGION(region);
-	size_t bytes_used = node->bytes_used - original_size;
-	node->bytes_used = bytes_used;
-
-#if !TARGET_OS_EMBEDDED // Always madvise for embedded platforms
-	/* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
-	if (szone->num_small_magazines == 1) { // Uniprocessor, single magazine, so no recirculation necessary
-		/* NOTHING */
-	} else if (DEPOT_MAGAZINE_INDEX != mag_index) {
-		// Emptiness discriminant
-		if (bytes_used < DENSITY_THRESHOLD(SMALL_REGION_PAYLOAD_BYTES)) {
-			/* Region has crossed threshold from density to sparsity. Mark it "suitable" on the
-			 recirculation candidates list. */
-			node->recirc_suitable = TRUE;
-		} else {
-			/* After this free, we've found the region is still dense, so it must have been even more so before
-			 the free. That implies the region is already correctly marked. Do nothing. */
-		}
-
-		// Has the entire magazine crossed the "emptiness threshold"? If so, transfer a region
-		// from this magazine to the Depot. Choose a region that itself has crossed the emptiness threshold (i.e
-		// is at least fraction "f" empty.) Such a region will be marked "suitable" on the recirculation list.
-
-		size_t a = small_mag_ptr->num_bytes_in_magazine; // Total bytes allocated to this magazine
-		size_t u = small_mag_ptr->mag_num_bytes_in_objects; // In use (malloc'd) from this magaqzine
-
-		if (a - u > ((3 * SMALL_REGION_PAYLOAD_BYTES) / 2) && u < DENSITY_THRESHOLD(a)) {
-			return small_free_do_recirc_to_depot(szone, small_mag_ptr, mag_index);
-		}
-
-	} else {
-#endif
-		// Freed to Depot. N.B. Lock on small_magazines[DEPOT_MAGAZINE_INDEX] is already held
-		// Calcuate the first page in the coalesced block that would be safe to mark MADV_FREE
-		size_t free_header_size = sizeof(free_list_t) + sizeof(msize_t);
-		uintptr_t safe_ptr = (uintptr_t)ptr + free_header_size;
-		uintptr_t round_safe = round_page_quanta(safe_ptr);
-
-		// Calcuate the last page in the coalesced block that would be safe to mark MADV_FREE
-		size_t free_tail_size = sizeof(msize_t);
-		uintptr_t safe_extent = (uintptr_t)ptr + SMALL_BYTES_FOR_MSIZE(msize) - free_tail_size;
-		uintptr_t trunc_extent = trunc_page_quanta(safe_extent);
-
-		// The newly freed block may complete a span of bytes that cover one or more pages. Mark the span with MADV_FREE.
-		if (round_safe < trunc_extent) { // Coalesced area covers a page (perhaps many)
-			// Extend the freed block by the free region header and tail sizes to include pages
-			// we may have coalesced that no longer host free region tails and headers.
-			// This may extend over in-use ranges, but the MIN/MAX clamping below will fix that up.
-			uintptr_t lo = trunc_page_quanta((uintptr_t)original_ptr - free_tail_size);
-			uintptr_t hi = round_page_quanta((uintptr_t)original_ptr + original_size + free_header_size);
-
-			uintptr_t free_lo = MAX(round_safe, lo);
-			uintptr_t free_hi = MIN(trunc_extent, hi);
-
-			if (free_lo < free_hi) {
-				small_free_list_remove_ptr(szone, small_mag_ptr, ptr, msize);
-				small_meta_header_set_in_use(meta_headers, index, msize);
-
-				OSAtomicIncrement32Barrier(&(node->pinned_to_depot));
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				madvise_free_range(szone, region, free_lo, free_hi, &szone->last_small_advise);
-				SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-				OSAtomicDecrement32Barrier(&(node->pinned_to_depot));
-
-				small_meta_header_set_is_free(meta_headers, index, msize);
-				small_free_list_add_ptr(szone, small_mag_ptr, ptr, msize);
-			}
-		}
-
-#if !TARGET_OS_EMBEDDED
-		if (0 < bytes_used || 0 < node->pinned_to_depot) {
-			/* Depot'd region is still live. Leave it in place on the Depot's recirculation list
-			 so as to avoid thrashing between the Depot's free list and a magazines's free list
-			 with detach_region/reattach_region */
-		} else {
-			/* Depot'd region is just now empty. Consider return to OS. */
-			region_t r_dealloc = small_free_try_depot_unmap_no_lock(szone, small_mag_ptr, node);
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-			if (r_dealloc)
-				deallocate_pages(szone, r_dealloc, SMALL_REGION_SIZE, 0);
-			return FALSE; // Caller need not unlock
-		}
-	}
-#endif
-
-	return TRUE; // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr)
-}
-
-// Allocates from the last region or a freshly allocated region
-static void *
-small_malloc_from_region_no_lock(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index,
-								 msize_t msize, void *aligned_address)
-{
-	void	*ptr;
-
-	// Before anything we transform the mag_bytes_free_at_end or mag_bytes_free_at_start - if any - to a regular free block
-	/* FIXME: last_block needs to be coalesced with previous entry if free, <rdar://5462322> */
-	if (small_mag_ptr->mag_bytes_free_at_end || small_mag_ptr->mag_bytes_free_at_start)
-		small_finalize_region(szone, small_mag_ptr);
-
-	// Here find the only place in smallville that (infrequently) takes the small_regions_lock.
-	// Only one thread at a time should be permitted to assess the density of the hash
-	// ring and adjust if needed.
-	// Only one thread at a time should be permitted to insert its new region on
-	// the hash ring.
-	// It is safe for all other threads to read the hash ring (hashed_regions) and
-	// the associated sizes (num_regions_allocated and num_small_regions).
-
-	_malloc_lock_lock(&szone->small_regions_lock);
-	// Check to see if the hash ring of small regions needs to grow.  Try to
-	// avoid the hash ring becoming too dense.
-	if (szone->small_region_generation->num_regions_allocated < (2 * szone->num_small_regions)) {
-		region_t *new_regions;
-		size_t new_size;
-		size_t new_shift = szone->small_region_generation->num_regions_allocated_shift; // In/Out parameter
-		new_regions = hash_regions_grow_no_lock(szone, szone->small_region_generation->hashed_regions,
-												szone->small_region_generation->num_regions_allocated,
-												&new_shift,
-												&new_size);
-		// Do not deallocate the current hashed_regions allocation since someone
-		// may be iterating it.  Instead, just leak it.
-
-		// Prepare to advance to the "next generation" of the hash ring.
-		szone->small_region_generation->nextgen->hashed_regions = new_regions;
-		szone->small_region_generation->nextgen->num_regions_allocated = new_size;
-		szone->small_region_generation->nextgen->num_regions_allocated_shift = new_shift;
-
-		// Throw the switch to atomically advance to the next generation.
-		szone->small_region_generation = szone->small_region_generation->nextgen;
-		// Ensure everyone sees the advance.
-		OSMemoryBarrier();
-	}
-	// Tag the region at "aligned_address" as belonging to us,
-	// and so put it under the protection of the magazine lock we are holding.
-	// Do this before advertising "aligned_address" on the hash ring(!)
-	MAGAZINE_INDEX_FOR_SMALL_REGION(aligned_address) = mag_index;
-
-	// Insert the new region into the hash ring, and update malloc statistics
-	hash_region_insert_no_lock(szone->small_region_generation->hashed_regions,
-							   szone->small_region_generation->num_regions_allocated,
-							   szone->small_region_generation->num_regions_allocated_shift,
-							   aligned_address);
-
-	szone->num_small_regions++;
-
-	_malloc_lock_unlock(&szone->small_regions_lock);
-
-	small_mag_ptr->mag_last_region = aligned_address;
-	BYTES_USED_FOR_SMALL_REGION(aligned_address) = SMALL_BYTES_FOR_MSIZE(msize);
-#if ASLR_INTERNAL
-	int offset_msize = malloc_entropy[1] & SMALL_ENTROPY_MASK;
-#if DEBUG_MALLOC
-	if (getenv("MallocASLRForce")) offset_msize = strtol(getenv("MallocASLRForce"), NULL, 0) & SMALL_ENTROPY_MASK;
-	if (getenv("MallocASLRPrint")) malloc_printf("Region: %p offset: %d\n", aligned_address, offset_msize);
-#endif
-#else
-	int offset_msize = 0;
-#endif
-	ptr = (void *)((uintptr_t) aligned_address + SMALL_BYTES_FOR_MSIZE(offset_msize));
-	small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), offset_msize, msize);
-	small_mag_ptr->mag_num_objects++;
-	small_mag_ptr->mag_num_bytes_in_objects += SMALL_BYTES_FOR_MSIZE(msize);
-	small_mag_ptr->num_bytes_in_magazine += SMALL_REGION_PAYLOAD_BYTES;
-
-	// add a big free block at the end
-	small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), offset_msize + msize, NUM_SMALL_BLOCKS - msize - offset_msize);
-	small_mag_ptr->mag_bytes_free_at_end = SMALL_BYTES_FOR_MSIZE(NUM_SMALL_BLOCKS - msize - offset_msize);
-
-#if ASLR_INTERNAL
-	// add a big free block at the start
-	small_mag_ptr->mag_bytes_free_at_start = SMALL_BYTES_FOR_MSIZE(offset_msize);
-	if (offset_msize) {
-		small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), 0, offset_msize);
-	}
-#else
-	small_mag_ptr->mag_bytes_free_at_start = 0;
-#endif
-
-	// connect to magazine as last node
-	recirc_list_splice_last(szone, small_mag_ptr, REGION_TRAILER_FOR_SMALL_REGION(aligned_address));
-
-	return ptr;
-}
-
-static INLINE void *
-small_try_shrink_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_good_size)
-{
-	msize_t new_msize = SMALL_MSIZE_FOR_BYTES(new_good_size);
-	msize_t mshrinkage = SMALL_MSIZE_FOR_BYTES(old_size) - new_msize;
-
-	if (mshrinkage) {
-		void *q = (void *)((uintptr_t)ptr + SMALL_BYTES_FOR_MSIZE(new_msize));
-		magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->small_magazines,
-																	 REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)),
-																	 MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)));
-
-		// Mark q as block header and in-use, thus creating two blocks.
-		small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), SMALL_META_INDEX_FOR_PTR(ptr), new_msize);
-		small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(q), SMALL_META_INDEX_FOR_PTR(q), mshrinkage);
-		small_mag_ptr->mag_num_objects++;
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone,small_mag_ptr);
-		szone_free(szone, q); // avoid inlining free_small(szone, q, ...);
-	}
-
-	return ptr;
-}
-
-static INLINE boolean_t
-small_try_realloc_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_size)
-{
-	// returns 1 on success
-	msize_t	*meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
-	unsigned	index;
-	msize_t	old_msize, new_msize;
-	unsigned	next_index;
-	void	*next_block;
-	msize_t	next_msize_and_free;
-	boolean_t	is_free;
-	msize_t	next_msize, leftover_msize;
-	void	*leftover;
-
-	index = SMALL_META_INDEX_FOR_PTR(ptr);
-	old_msize = SMALL_MSIZE_FOR_BYTES(old_size);
-	new_msize = SMALL_MSIZE_FOR_BYTES(new_size + SMALL_QUANTUM - 1);
-	next_index = index + old_msize;
-
-	if (next_index >= NUM_SMALL_BLOCKS) {
-		return 0;
-	}
-	next_block = (char *)ptr + old_size;
-
-#if DEBUG_MALLOC
-	if ((uintptr_t)next_block & (SMALL_QUANTUM - 1)) {
-		szone_error(szone, 1, "internal invariant broken in realloc(next_block)", next_block, NULL);
-	}
-	if (meta_headers[index] != old_msize)
-		malloc_printf("*** small_try_realloc_in_place incorrect old %d %d\n",
-					  meta_headers[index], old_msize);
-#endif
-
-	magazine_t	*small_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->small_magazines,
-																  REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)),
-																  MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)));
-	if (DEPOT_MAGAZINE_INDEX == MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr)))
-	{
-	    SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-	    return 0;
-	}
-
-
-	/*
-	 * Look for a free block immediately afterwards.  If it's large enough, we can consume (part of)
-	 * it.
-	 */
-	next_msize_and_free = meta_headers[next_index];
-	is_free = next_msize_and_free & SMALL_IS_FREE;
-	if (!is_free) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-		return 0; // next_block is in use;
-	}
-	next_msize = next_msize_and_free & ~ SMALL_IS_FREE;
-	if (old_msize + next_msize < new_msize) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-		return 0; // even with next block, not enough
-	}
-	/*
-	 * The following block is big enough; pull it from its freelist and chop off enough to satisfy
-	 * our needs.
-	 */
-	small_free_list_remove_ptr(szone, small_mag_ptr, next_block, next_msize);
-	small_meta_header_set_middle(meta_headers, next_index);
-	leftover_msize = old_msize + next_msize - new_msize;
-	if (leftover_msize) {
-		/* there's some left, so put the remainder back */
-		leftover = (unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(new_msize);
-
-		small_free_list_add_ptr(szone, small_mag_ptr, leftover, leftover_msize);
-	}
-#if DEBUG_MALLOC
-	if (SMALL_BYTES_FOR_MSIZE(new_msize) > szone->large_threshold) {
-		malloc_printf("*** realloc in place for %p exceeded msize=%d\n", new_msize);
-	}
-#endif
-	small_meta_header_set_in_use(meta_headers, index, new_msize);
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in small_try_realloc_in_place(), ptr=%p, msize=%d\n", ptr, *SMALL_METADATA_FOR_PTR(ptr));
-	}
-#endif
-	small_mag_ptr->mag_num_bytes_in_objects += SMALL_BYTES_FOR_MSIZE(new_msize - old_msize);
-
-	// Update this region's bytes in use count
-	region_trailer_t *node = REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
-	size_t bytes_used = node->bytes_used + SMALL_BYTES_FOR_MSIZE(new_msize - old_msize);
-	node->bytes_used = bytes_used;
-
-	// Emptiness discriminant
-	if (bytes_used < DENSITY_THRESHOLD(SMALL_REGION_PAYLOAD_BYTES)) {
-		/* After this reallocation the region is still sparse, so it must have been even more so before
-		 the reallocation. That implies the region is already correctly marked. Do nothing. */
-	} else {
-		/* Region has crossed threshold from sparsity to density. Mark it not "suitable" on the
-		 recirculation candidates list. */
-		node->recirc_suitable = FALSE;
-	}
-
-	SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-	CHECK(szone, __PRETTY_FUNCTION__);
-	return 1;
-}
-
-static boolean_t
-small_check_region(szone_t *szone, region_t region)
-{
-	unsigned char	*ptr = SMALL_REGION_ADDRESS(region);
-	msize_t		*meta_headers = SMALL_META_HEADER_FOR_PTR(ptr);
-	unsigned char	*region_end = SMALL_REGION_END(region);
-	msize_t		prev_free = 0;
-	unsigned		index;
-	msize_t		msize_and_free;
-	msize_t		msize;
-	free_list_t		*free_head;
-	void		*previous, *next;
-	msize_t		*follower;
-	mag_index_t		mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
-	magazine_t		*small_mag_ptr = &(szone->small_magazines[mag_index]);
-
-	// Assumes locked
-	CHECK_MAGAZINE_PTR_LOCKED(szone, small_mag_ptr, __PRETTY_FUNCTION__);
-
-	if (region == small_mag_ptr->mag_last_region) {
-		ptr += small_mag_ptr->mag_bytes_free_at_start;
-		region_end -= small_mag_ptr->mag_bytes_free_at_end;
-	}
-
-	while (ptr < region_end) {
-		index = SMALL_META_INDEX_FOR_PTR(ptr);
-		msize_and_free = meta_headers[index];
-		if (!(msize_and_free & SMALL_IS_FREE)) {
-			// block is in use
-			msize = msize_and_free;
-			if (!msize) {
-				malloc_printf("*** invariant broken: null msize ptr=%p num_small_regions=%d end=%p\n",
-							  ptr, szone->num_small_regions, region_end);
-				return 0;
-			}
-#if !RELAXED_INVARIANT_CHECKS
-			if (SMALL_BYTES_FOR_MSIZE(msize) > szone->large_threshold) {
-				malloc_printf("*** invariant broken for %p this small msize=%d - size is too large\n",
-							  ptr, msize_and_free);
-				return 0;
-			}
-#endif // RELAXED_INVARIANT_CHECKS
-			ptr += SMALL_BYTES_FOR_MSIZE(msize);
-			prev_free = 0;
-		} else {
-			// free pointer
-			msize = msize_and_free & ~ SMALL_IS_FREE;
-			free_head = (free_list_t *)ptr;
-			follower = (msize_t *)FOLLOWING_SMALL_PTR(ptr, msize);
-			if (!msize) {
-				malloc_printf("*** invariant broken for free block %p this msize=%d\n", ptr, msize);
-				return 0;
-			}
-#if !RELAXED_INVARIANT_CHECKS
-			if (prev_free) {
-				malloc_printf("*** invariant broken for %p (2 free in a row)\n", ptr);
-				return 0;
-			}
-#endif
-			previous = free_list_unchecksum_ptr(szone, &free_head->previous);
-			next = free_list_unchecksum_ptr(szone, &free_head->next);
-			if (previous && !SMALL_PTR_IS_FREE(previous)) {
-				malloc_printf("*** invariant broken for %p (previous %p is not a free pointer)\n",
-							  ptr, free_head->previous);
-				return 0;
-			}
-			if (next && !SMALL_PTR_IS_FREE(next)) {
-				malloc_printf("*** invariant broken for %p (next is not a free pointer)\n", ptr);
-				return 0;
-			}
-			if (SMALL_PREVIOUS_MSIZE(follower) != msize) {
-				malloc_printf("*** invariant broken for small free %p followed by %p in region [%p-%p] "
-							  "(end marker incorrect) should be %d; in fact %d\n",
-							  ptr, follower, SMALL_REGION_ADDRESS(region), region_end, msize, SMALL_PREVIOUS_MSIZE(follower));
-				return 0;
-			}
-			ptr = (unsigned char *)follower;
-			prev_free = SMALL_IS_FREE;
-		}
-	}
-	return 1;
-}
-
-static kern_return_t
-small_in_use_enumerator(task_t task, void *context, unsigned type_mask, szone_t *szone,
-						memory_reader_t reader, vm_range_recorder_t recorder)
-{
-	size_t		num_regions;
-	size_t		index;
-	region_t		*regions;
-	vm_range_t		buffer[MAX_RECORDER_BUFFER];
-	unsigned		count = 0;
-	kern_return_t	err;
-	region_t		region;
-	vm_range_t		range;
-	vm_range_t		admin_range;
-	vm_range_t		ptr_range;
-	unsigned char	*mapped_region;
-	msize_t		*block_header;
-	unsigned		block_index;
-	unsigned		block_limit;
-	msize_t		msize_and_free;
-	msize_t		msize;
-	magazine_t          *small_mag_base = NULL;
-
-	region_hash_generation_t *srg_ptr;
-	err = reader(task, (vm_address_t)szone->small_region_generation, sizeof(region_hash_generation_t), (void **)&srg_ptr);
-	if (err) return err;
-
-	num_regions = srg_ptr->num_regions_allocated;
-	err = reader(task, (vm_address_t)srg_ptr->hashed_regions, sizeof(region_t) * num_regions, (void **)&regions);
-	if (err) return err;
-
-	if (type_mask & MALLOC_PTR_IN_USE_RANGE_TYPE) {
-		// Map in all active magazines. Do this outside the iteration over regions.
-		err = reader(task, (vm_address_t)(szone->small_magazines),
-					 szone->num_small_magazines*sizeof(magazine_t),(void **)&small_mag_base);
-		if (err) return err;
-	}
-
-	for (index = 0; index < num_regions; ++index) {
-		region = regions[index];
-		if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
-			range.address = (vm_address_t)SMALL_REGION_ADDRESS(region);
-			range.size = SMALL_REGION_SIZE;
-			if (type_mask & MALLOC_ADMIN_REGION_RANGE_TYPE) {
-				admin_range.address = range.address + SMALL_METADATA_START;
-				admin_range.size = SMALL_METADATA_SIZE;
-				recorder(task, context, MALLOC_ADMIN_REGION_RANGE_TYPE, &admin_range, 1);
-			}
-			if (type_mask & (MALLOC_PTR_REGION_RANGE_TYPE | MALLOC_ADMIN_REGION_RANGE_TYPE)) {
-				ptr_range.address = range.address;
-				ptr_range.size = NUM_SMALL_BLOCKS * SMALL_QUANTUM;
-				recorder(task, context, MALLOC_PTR_REGION_RANGE_TYPE, &ptr_range, 1);
-			}
-			if (type_mask & MALLOC_PTR_IN_USE_RANGE_TYPE) {
-				void 		*mag_last_free;
-				vm_address_t	mag_last_free_ptr = 0;
-				msize_t		mag_last_free_msize = 0;
-
-				err = reader(task, range.address, range.size, (void **)&mapped_region);
-				if (err)
-					return err;
-
-				mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(mapped_region);
-				magazine_t *small_mag_ptr = small_mag_base + mag_index;
-
-				if (DEPOT_MAGAZINE_INDEX != mag_index) {
-					mag_last_free = small_mag_ptr->mag_last_free;
-					if (mag_last_free) {
-						mag_last_free_ptr = (uintptr_t) mag_last_free & ~(SMALL_QUANTUM - 1);
-						mag_last_free_msize = (uintptr_t) mag_last_free & (SMALL_QUANTUM - 1);
-					}
-				} else {
-					for (mag_index = 0; mag_index < szone->num_small_magazines; mag_index++) {
-						if ((void *)range.address == (small_mag_base + mag_index)->mag_last_free_rgn) {
-							mag_last_free = (small_mag_base + mag_index)->mag_last_free;
-							if (mag_last_free) {
-								mag_last_free_ptr = (uintptr_t) mag_last_free & ~(SMALL_QUANTUM - 1);
-								mag_last_free_msize = (uintptr_t) mag_last_free & (SMALL_QUANTUM - 1);
-							}
-						}
-					}
-				}
-
-				block_header = (msize_t *)(mapped_region + SMALL_METADATA_START + sizeof(region_trailer_t));
-				block_index = 0;
-				block_limit = NUM_SMALL_BLOCKS;
-				if (region == small_mag_ptr->mag_last_region) {
-					block_index += SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_start);
-					block_limit -= SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end);
-				}
-				while (block_index < block_limit) {
-					msize_and_free = block_header[block_index];
-					msize = msize_and_free & ~ SMALL_IS_FREE;
-					if (! (msize_and_free & SMALL_IS_FREE) &&
-						range.address + SMALL_BYTES_FOR_MSIZE(block_index) != mag_last_free_ptr) {
-						// Block in use
-						buffer[count].address = range.address + SMALL_BYTES_FOR_MSIZE(block_index);
-						buffer[count].size = SMALL_BYTES_FOR_MSIZE(msize);
-						count++;
-						if (count >= MAX_RECORDER_BUFFER) {
-							recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE, buffer, count);
-							count = 0;
-						}
-					}
-
-					if (!msize)
-						return KERN_FAILURE; // Somethings amiss. Avoid looping at this block_index.
-
-					block_index += msize;
-				}
-				if (count) {
-					recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE, buffer, count);
-					count = 0;
-				}
-			}
-		}
-	}
-	return 0;
-}
-
-static void *
-small_malloc_from_free_list(szone_t *szone, magazine_t *small_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	free_list_t		*ptr;
-	msize_t		this_msize;
-	grain_t		slot = (msize <= szone->num_small_slots) ? msize - 1 : szone->num_small_slots - 1;
-	free_list_t		**free_list = small_mag_ptr->mag_free_list;
-	free_list_t		**the_slot = free_list + slot;
-	free_list_t		*next;
-	free_list_t		**limit;
-	unsigned		bitmap;
-	msize_t		leftover_msize;
-	free_list_t		*leftover_ptr;
-
-	// Assumes we've locked the region
-	CHECK_MAGAZINE_PTR_LOCKED(szone, small_mag_ptr, __PRETTY_FUNCTION__);
-
-	// Look for an exact match by checking the freelist for this msize.
-	//
-	ptr = *the_slot;
-	if (ptr) {
-		next = free_list_unchecksum_ptr(szone, &ptr->next);
-		if (next) {
-			next->previous = ptr->previous;
-		} else {
-			BITMAPN_CLR(small_mag_ptr->mag_bitmap, slot);
-		}
-		*the_slot = next;
-		this_msize = msize;
-		goto return_small_alloc;
-	}
-
-	// Mask off the bits representing slots holding free blocks smaller than
-	// the size we need.  If there are no larger free blocks, try allocating
-	// from the free space at the end of the small region.
-	if (szone->is_largemem) {
-		// BITMAPN_CTZ implementation
-		unsigned idx = slot >> 5;
-		bitmap = 0;
-		unsigned mask = ~ ((1 << (slot & 31)) - 1);
-		for ( ; idx < SMALL_BITMAP_WORDS; ++idx ) {
-			bitmap = small_mag_ptr->mag_bitmap[idx] & mask;
-			if (bitmap != 0)
-				break;
-			mask = ~0U;
-		}
-		// Check for fallthrough: No bits set in bitmap
-		if ((bitmap == 0) && (idx == SMALL_BITMAP_WORDS))
-			goto try_small_from_end;
-
-		// Start looking at the first set bit, plus 32 bits for every word of
-		// zeroes or entries that were too small.
-		slot = BITMAP32_CTZ((&bitmap)) + (idx * 32);
-	} else {
-		bitmap = small_mag_ptr->mag_bitmap[0] & ~ ((1 << slot) - 1);
-		if (!bitmap)
-			goto try_small_from_end;
-
-		slot = BITMAP32_CTZ((&bitmap));
-	}
-	// FIXME: Explain use of - 1 here, last slot has special meaning
-	limit = free_list + szone->num_small_slots - 1;
-	free_list += slot;
-
-	if (free_list < limit) {
-		ptr = *free_list;
-		if (ptr) {
-
-			next = free_list_unchecksum_ptr(szone, &ptr->next);
-			*free_list = next;
-			if (next) {
-				next->previous = ptr->previous;
-			} else {
-				BITMAPN_CLR(small_mag_ptr->mag_bitmap, slot);
-			}
-			this_msize = SMALL_PTR_SIZE(ptr);
-			goto add_leftover_and_proceed;
-		}
-#if DEBUG_MALLOC
-		malloc_printf("in small_malloc_from_free_list(), mag_bitmap out of sync, slot=%d\n",slot);
-#endif
-	}
-
-	// We are now looking at the last slot, which contains blocks equal to, or
-	// due to coalescing of free blocks, larger than (num_small_slots - 1) * (small quantum size).
-	// If the last freelist is not empty, and the head contains a block that is
-	// larger than our request, then the remainder is put back on the free list.
-	//
-	ptr = *limit;
-	if (ptr) {
-		this_msize = SMALL_PTR_SIZE(ptr);
-		next = free_list_unchecksum_ptr(szone, &ptr->next);
-		if (this_msize - msize >= szone->num_small_slots) {
-			// the leftover will go back to the free list, so we optimize by
-			// modifying the free list rather than a pop and push of the head
-			leftover_msize = this_msize - msize;
-			leftover_ptr = (free_list_t *)((unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(msize));
-			*limit = leftover_ptr;
-			if (next) {
-				next->previous.u = free_list_checksum_ptr(szone, leftover_ptr);
-			}
-			leftover_ptr->previous = ptr->previous;
-			leftover_ptr->next = ptr->next;
-			small_meta_header_set_is_free(SMALL_META_HEADER_FOR_PTR(leftover_ptr),
-										  SMALL_META_INDEX_FOR_PTR(leftover_ptr), leftover_msize);
-			// Store msize at the end of the block denoted by "leftover_ptr" (i.e. at a negative offset from follower)
-			SMALL_PREVIOUS_MSIZE(FOLLOWING_SMALL_PTR(leftover_ptr, leftover_msize)) = leftover_msize; // Access is safe
-#if DEBUG_MALLOC
-			if (LOG(szone,ptr)) {
-				malloc_printf("in small_malloc_from_free_list(), last slot ptr=%p, msize=%d this_msize=%d\n", ptr, msize, this_msize);
-			}
-#endif
-			this_msize = msize;
-			goto return_small_alloc;
-		}
-		if (next) {
-			next->previous = ptr->previous;
-		}
-		*limit = next;
-		goto add_leftover_and_proceed;
-	}
-
-try_small_from_end:
-	// Let's see if we can use small_mag_ptr->mag_bytes_free_at_end
-	if (small_mag_ptr->mag_bytes_free_at_end >= SMALL_BYTES_FOR_MSIZE(msize)) {
-		ptr = (free_list_t *)(SMALL_REGION_END(small_mag_ptr->mag_last_region) -
-							  small_mag_ptr->mag_bytes_free_at_end);
-		small_mag_ptr->mag_bytes_free_at_end -= SMALL_BYTES_FOR_MSIZE(msize);
-		if (small_mag_ptr->mag_bytes_free_at_end) {
-			// let's mark this block as in use to serve as boundary
-			small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr),
-										 SMALL_META_INDEX_FOR_PTR((unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(msize)),
-										 SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_end));
-		}
-		this_msize = msize;
-		goto return_small_alloc;
-	}
-#if ASLR_INTERNAL
-	// Try from start if nothing left at end
-	if (small_mag_ptr->mag_bytes_free_at_start >= SMALL_BYTES_FOR_MSIZE(msize)) {
-		ptr = (free_list_t *)(SMALL_REGION_ADDRESS(small_mag_ptr->mag_last_region) +
-							  small_mag_ptr->mag_bytes_free_at_start - SMALL_BYTES_FOR_MSIZE(msize));
-		small_mag_ptr->mag_bytes_free_at_start -= SMALL_BYTES_FOR_MSIZE(msize);
-		if (small_mag_ptr->mag_bytes_free_at_start) {
-			// let's mark this block as in use to serve as boundary
-			small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), 0, SMALL_MSIZE_FOR_BYTES(small_mag_ptr->mag_bytes_free_at_start));
-		}
-		this_msize = msize;
-		goto return_small_alloc;
-	}
-#endif
-	return NULL;
-
-add_leftover_and_proceed:
-	if (this_msize > msize) {
-		leftover_msize = this_msize - msize;
-		leftover_ptr = (free_list_t *)((unsigned char *)ptr + SMALL_BYTES_FOR_MSIZE(msize));
-#if DEBUG_MALLOC
-		if (LOG(szone,ptr)) {
-			malloc_printf("in small_malloc_from_free_list(), adding leftover ptr=%p, this_msize=%d\n", ptr, this_msize);
-		}
-#endif
-		small_free_list_add_ptr(szone, small_mag_ptr, leftover_ptr, leftover_msize);
-		this_msize = msize;
-	}
-
-return_small_alloc:
-	small_mag_ptr->mag_num_objects++;
-	small_mag_ptr->mag_num_bytes_in_objects += SMALL_BYTES_FOR_MSIZE(this_msize);
-
-	// Update this region's bytes in use count
-	region_trailer_t *node = REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
-	size_t bytes_used = node->bytes_used + SMALL_BYTES_FOR_MSIZE(this_msize);
-	node->bytes_used = bytes_used;
-
-	// Emptiness discriminant
-	if (bytes_used < DENSITY_THRESHOLD(SMALL_REGION_PAYLOAD_BYTES)) {
-		/* After this allocation the region is still sparse, so it must have been even more so before
-		 the allocation. That implies the region is already correctly marked. Do nothing. */
-	} else {
-		/* Region has crossed threshold from sparsity to density. Mark in not "suitable" on the
-		 recirculation candidates list. */
-		node->recirc_suitable = FALSE;
-	}
-#if DEBUG_MALLOC
-	if (LOG(szone,ptr)) {
-		malloc_printf("in small_malloc_from_free_list(), ptr=%p, this_msize=%d, msize=%d\n", ptr, this_msize, msize);
-	}
-#endif
-	small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(ptr), SMALL_META_INDEX_FOR_PTR(ptr), this_msize);
-	return ptr;
-}
-#undef DENSITY_THRESHOLD
-#undef K
-
-static INLINE void *
-small_malloc_should_clear(szone_t *szone, msize_t msize, boolean_t cleared_requested)
-{
-	void	*ptr;
-	mag_index_t	mag_index = mag_get_thread_index(szone);
-	magazine_t	*small_mag_ptr = &(szone->small_magazines[mag_index]);
-
-	SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-
-#if SMALL_CACHE
-	ptr = (void *)small_mag_ptr->mag_last_free;
-
-	if ((((uintptr_t)ptr) & (SMALL_QUANTUM - 1)) == msize) {
-		// we have a winner
-		small_mag_ptr->mag_last_free = NULL;
-		small_mag_ptr->mag_last_free_rgn = NULL;
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-		CHECK(szone, __PRETTY_FUNCTION__);
-		ptr = (void *)((uintptr_t)ptr & ~ (SMALL_QUANTUM - 1));
-		if (cleared_requested) {
-			memset(ptr, 0, SMALL_BYTES_FOR_MSIZE(msize));
-		}
-		return ptr;
-	}
-#endif /* SMALL_CACHE */
-
-	while(1) {
-		ptr = small_malloc_from_free_list(szone, small_mag_ptr, mag_index, msize);
-		if (ptr) {
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-			CHECK(szone, __PRETTY_FUNCTION__);
-			if (cleared_requested) {
-				memset(ptr, 0, SMALL_BYTES_FOR_MSIZE(msize));
-			}
-			return ptr;
-		}
-
-		if (small_get_region_from_depot(szone, small_mag_ptr, mag_index, msize)) {
-			ptr = small_malloc_from_free_list(szone, small_mag_ptr, mag_index, msize);
-			if (ptr) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				CHECK(szone, __PRETTY_FUNCTION__);
-				if (cleared_requested) {
-					memset(ptr, 0, SMALL_BYTES_FOR_MSIZE(msize));
-				}
-				return ptr;
-			}
-		}
-
-		// The magazine is exhausted. A new region (heap) must be allocated to satisfy this call to malloc().
-		// The allocation, an mmap() system call, will be performed outside the magazine spin locks by the first
-		// thread that suffers the exhaustion. That thread sets "alloc_underway" and enters a critical section.
-		// Threads arriving here later are excluded from the critical section, yield the CPU, and then retry the
-		// allocation. After some time the magazine is resupplied, the original thread leaves with its allocation,
-		// and retry-ing threads succeed in the code just above.
-		if (!small_mag_ptr->alloc_underway) {
-			void *fresh_region;
-
-			// time to create a new region (do this outside the magazine lock)
-			small_mag_ptr->alloc_underway = TRUE;
-			OSMemoryBarrier();
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-			fresh_region = allocate_pages_securely(szone, SMALL_REGION_SIZE, SMALL_BLOCKS_ALIGN, VM_MEMORY_MALLOC_SMALL);
-			SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-
-			MAGMALLOC_ALLOCREGION((void *)szone, (int)mag_index, fresh_region, SMALL_REGION_SIZE); // DTrace USDT Probe
-
-			if (!fresh_region) { // out of memory!
-				small_mag_ptr->alloc_underway = FALSE;
-				OSMemoryBarrier();
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				return NULL;
-			}
-
-			ptr = small_malloc_from_region_no_lock(szone, small_mag_ptr, mag_index, msize, fresh_region);
-
-			// we don't clear because this freshly allocated space is pristine
-			small_mag_ptr->alloc_underway = FALSE;
-			OSMemoryBarrier();
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-			CHECK(szone, __PRETTY_FUNCTION__);
-			return ptr;
-		} else {
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-			yield();
-			SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-		}
-	}
-	/* NOTREACHED */
-}
-
-static NOINLINE void
-free_small_botch(szone_t *szone, free_list_t *ptr)
-{
-	mag_index_t	mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
-	magazine_t	*small_mag_ptr = &(szone->small_magazines[mag_index]);
-	SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-	szone_error(szone, 1, "double free", ptr, NULL);
-}
-
-static INLINE void
-free_small(szone_t *szone, void *ptr, region_t small_region, size_t known_size)
-{
-	msize_t	msize;
-	mag_index_t	mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
-	magazine_t	*small_mag_ptr = &(szone->small_magazines[mag_index]);
-
-	// ptr is known to be in small_region
-	if (known_size) {
-		msize = SMALL_MSIZE_FOR_BYTES(known_size + SMALL_QUANTUM - 1);
-	} else {
-		msize = SMALL_PTR_SIZE(ptr);
-		if (SMALL_PTR_IS_FREE(ptr)) {
-			free_small_botch(szone, ptr);
-			return;
-		}
-	}
-
-	SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-
-#if SMALL_CACHE
-	// Depot does not participate in SMALL_CACHE since it can't be directly malloc()'d
-	if (DEPOT_MAGAZINE_INDEX != mag_index) {
-
-		void *ptr2 = small_mag_ptr->mag_last_free; // Might be NULL
-		region_t rgn2 = small_mag_ptr->mag_last_free_rgn;
-
-		/* check that we don't already have this pointer in the cache */
-		if (ptr == (void *)((uintptr_t)ptr2 & ~ (SMALL_QUANTUM - 1))) {
-			free_small_botch(szone, ptr);
-			return;
-		}
-
-		if ((szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE) && msize)
-			memset(ptr, SCRABBLE_BYTE, SMALL_BYTES_FOR_MSIZE(msize));
-
-		small_mag_ptr->mag_last_free = (void *)(((uintptr_t)ptr) | msize);
-		small_mag_ptr->mag_last_free_rgn = small_region;
-
-		if (!ptr2) {
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-			CHECK(szone, __PRETTY_FUNCTION__);
-			return;
-		}
-
-		msize = (uintptr_t)ptr2 & (SMALL_QUANTUM - 1);
-		ptr = (void *)(((uintptr_t)ptr2) & ~(SMALL_QUANTUM - 1));
-		small_region = rgn2;
-	}
-#endif /* SMALL_CACHE */
-
-	// Now in the time it took to acquire the lock, the region may have migrated
-	// from one magazine to another. I.e. trailer->mag_index is volatile.
-	// In which case the magazine lock we obtained (namely magazines[mag_index].mag_lock)
-	// is stale. If so, keep on tryin' ...
-	region_trailer_t *trailer = REGION_TRAILER_FOR_SMALL_REGION(small_region);
-	mag_index_t refreshed_index;
-
-	while (mag_index != (refreshed_index = trailer->mag_index)) { // Note assignment
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-
-		mag_index = refreshed_index;
-		small_mag_ptr = &(szone->small_magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-	}
-
-	if (small_free_no_lock(szone, small_mag_ptr, mag_index, small_region, ptr, msize))
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-
-	CHECK(szone, __PRETTY_FUNCTION__);
-}
-
-static void
-print_small_free_list(szone_t *szone)
-{
-	free_list_t		*ptr;
-	_SIMPLE_STRING	b = _simple_salloc();
-	mag_index_t mag_index;
-
-	if (b) {
-		_simple_sappend(b, "small free sizes:\n");
-		for (mag_index = -1; mag_index < szone->num_small_magazines; mag_index++) {
-			grain_t	slot = 0;
-			_simple_sprintf(b,"\tMagazine %d: ", mag_index);
-			while (slot < szone->num_small_slots) {
-				ptr = szone->small_magazines[mag_index].mag_free_list[slot];
-				if (ptr) {
-					_simple_sprintf(b, "%s%y[%d]; ", (slot == szone->num_small_slots-1) ? ">=" : "",
-									(slot + 1) * SMALL_QUANTUM, free_list_count(szone, ptr));
-				}
-				slot++;
-			}
-			_simple_sappend(b,"\n");
-		}
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-
-static void
-print_small_region(szone_t *szone, boolean_t verbose, region_t region, size_t bytes_at_start, size_t bytes_at_end)
-{
-	unsigned		counts[1024];
-	unsigned		in_use = 0;
-	uintptr_t		start = (uintptr_t)SMALL_REGION_ADDRESS(region);
-	uintptr_t		current = start + bytes_at_start;
-	uintptr_t		limit = (uintptr_t)SMALL_REGION_END(region) - bytes_at_end;
-	msize_t		msize_and_free;
-	msize_t		msize;
-	unsigned		ci;
-	_SIMPLE_STRING	b;
-	uintptr_t		pgTot = 0;
-
-	if (region == HASHRING_REGION_DEALLOCATED) {
-		if ((b = _simple_salloc()) != NULL) {
-			_simple_sprintf(b, "Small region [unknown address] was returned to the OS\n");
-			_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-			_simple_sfree(b);
-		}
-		return;
-	}
-
-	memset(counts, 0, sizeof(counts));
-	while (current < limit) {
-		msize_and_free = *SMALL_METADATA_FOR_PTR(current);
-		msize = msize_and_free & ~ SMALL_IS_FREE;
-		if (!msize) {
-			malloc_printf("*** error with %p: msize=%d\n", (void *)current, (unsigned)msize);
-			break;
-		}
-		if (!(msize_and_free & SMALL_IS_FREE)) {
-			// block in use
-			if (msize < 1024)
-				counts[msize]++;
-			in_use++;
-		} else {
-			uintptr_t pgLo = round_page_quanta(current + sizeof(free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_quanta(current + SMALL_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				pgTot += (pgHi - pgLo);
-			}
-		}
-		current += SMALL_BYTES_FOR_MSIZE(msize);
-	}
-	if ((b = _simple_salloc()) != NULL) {
-		_simple_sprintf(b, "Small region [%p-%p, %y] \t", (void *)start, SMALL_REGION_END(region), (int)SMALL_REGION_SIZE);
-		_simple_sprintf(b, "Magazine=%d \t", MAGAZINE_INDEX_FOR_SMALL_REGION(region));
-		_simple_sprintf(b, "Allocations in use=%d \t Bytes in use=%ly \t", in_use, BYTES_USED_FOR_SMALL_REGION(region));
-		if (bytes_at_end || bytes_at_start)
-			_simple_sprintf(b, "Untouched=%ly ", bytes_at_end + bytes_at_start);
-		if (DEPOT_MAGAZINE_INDEX == MAGAZINE_INDEX_FOR_SMALL_REGION(region)) {
-			_simple_sprintf(b, "Advised MADV_FREE=%ly", pgTot);
-		} else {
-			_simple_sprintf(b, "Fragments subject to reclamation=%ly", pgTot);
-		}
-		if (verbose && in_use) {
-			_simple_sappend(b, "\n\tSizes in use: ");
-			for (ci = 0; ci < 1024; ci++)
-				if (counts[ci])
-					_simple_sprintf(b, "%d[%d] ", SMALL_BYTES_FOR_MSIZE(ci), counts[ci]);
-		}
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-
-static boolean_t
-small_free_list_check(szone_t *szone, grain_t slot)
-{
-	mag_index_t mag_index;
-
-	for (mag_index = -1; mag_index < szone->num_small_magazines; mag_index++) {
-		magazine_t	*small_mag_ptr = &(szone->small_magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(szone, small_mag_ptr);
-
-		unsigned	count = 0;
-		free_list_t	*ptr = szone->small_magazines[mag_index].mag_free_list[slot];
-		msize_t		msize_and_free;
-		free_list_t	*previous = NULL;
-
-		while (ptr) {
-			msize_and_free = *SMALL_METADATA_FOR_PTR(ptr);
-			if (!(msize_and_free & SMALL_IS_FREE)) {
-				malloc_printf("*** in-use ptr in free list slot=%d count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				return 0;
-			}
-			if (((uintptr_t)ptr) & (SMALL_QUANTUM - 1)) {
-				malloc_printf("*** unaligned ptr in free list slot=%d  count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				return 0;
-			}
-			if (!small_region_for_ptr_no_lock(szone, ptr)) {
-				malloc_printf("*** ptr not in szone slot=%d  count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				return 0;
-			}
-			if (free_list_unchecksum_ptr(szone, &ptr->previous) != previous) {
-				malloc_printf("*** previous incorrectly set slot=%d  count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				return 0;
-			}
-			previous = ptr;
-			ptr = free_list_unchecksum_ptr(szone, &ptr->next);
-			count++;
-		}
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-	}
-	return 1;
-}
-
-/*******************************************************************************
- * Large allocator implementation
- ******************************************************************************/
-#pragma mark large allocator
-
-#if DEBUG_MALLOC
-
-static void
-large_debug_print(szone_t *szone)
-{
-	unsigned		index;
-	large_entry_t	*range;
-	_SIMPLE_STRING	b = _simple_salloc();
-
-	if (b) {
-		for (index = 0, range = szone->large_entries; index < szone->num_large_entries; index++, range++)
-			if (range->address)
-				_simple_sprintf(b, "%d: %p(%y);  ", index, range->address, range->size);
-
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-#endif
-
-/*
- * Scan the hash ring looking for an entry for the given pointer.
- */
-static large_entry_t *
-large_entry_for_pointer_no_lock(szone_t *szone, const void *ptr)
-{
-	// result only valid with lock held
-	unsigned		num_large_entries = szone->num_large_entries;
-	unsigned		hash_index;
-	unsigned		index;
-	large_entry_t	*range;
-
-	if (!num_large_entries)
-		return NULL;
-
-	hash_index = ((uintptr_t)ptr >> vm_page_quanta_shift) % num_large_entries;
-	index = hash_index;
-
-	do {
-		range = szone->large_entries + index;
-		if (range->address == (vm_address_t)ptr)
-			return range;
-		if (0 == range->address)
-			return NULL; // end of chain
-		index++;
-		if (index == num_large_entries)
-			index = 0;
-	} while (index != hash_index);
-
-	return NULL;
-}
-
-static void
-large_entry_insert_no_lock(szone_t *szone, large_entry_t range)
-{
-	unsigned		num_large_entries = szone->num_large_entries;
-	unsigned		hash_index = (((uintptr_t)(range.address)) >> vm_page_quanta_shift) % num_large_entries;
-	unsigned		index = hash_index;
-	large_entry_t	*entry;
-
-	// assert(szone->num_large_objects_in_use < szone->num_large_entries); /* must be called with room to spare */
-
-	do {
-		entry = szone->large_entries + index;
-		if (0 == entry->address) {
-			*entry = range;
-			return; // end of chain
-		}
-		index++;
-		if (index == num_large_entries)
-			index = 0;
-	} while (index != hash_index);
-
-	// assert(0); /* must not fallthrough! */
-}
-
-// FIXME: can't we simply swap the (now empty) entry with the last entry on the collision chain for this hash slot?
-static INLINE void
-large_entries_rehash_after_entry_no_lock(szone_t *szone, large_entry_t *entry)
-{
-	unsigned		num_large_entries = szone->num_large_entries;
-	unsigned		hash_index = entry - szone->large_entries;
-	unsigned		index = hash_index;
-	large_entry_t	range;
-
-	// assert(entry->address == 0) /* caller must have cleared *entry */
-
-	do {
-		index++;
-		if (index == num_large_entries)
-			index = 0;
-		range = szone->large_entries[index];
-		if (0 == range.address)
-			return;
-		szone->large_entries[index].address = (vm_address_t)0;
-		szone->large_entries[index].size = 0;
-		szone->large_entries[index].did_madvise_reusable = FALSE;
-		large_entry_insert_no_lock(szone, range); // this will reinsert in the
-		// proper place
-	} while (index != hash_index);
-
-	// assert(0); /* since entry->address == 0, must not fallthrough! */
-}
-
-// FIXME: num should probably be a size_t, since you can theoretically allocate
-// more than 2^32-1 large_threshold objects in 64 bit.
-static INLINE large_entry_t *
-large_entries_alloc_no_lock(szone_t *szone, unsigned num)
-{
-	size_t	size = num * sizeof(large_entry_t);
-
-	// Note that we allocate memory (via a system call) under a spin lock
-	// That is certainly evil, however it's very rare in the lifetime of a process
-	// The alternative would slow down the normal case
-	return allocate_pages(szone, round_page_quanta(size), 0, 0, VM_MEMORY_MALLOC_LARGE);
-}
-
-static void
-large_entries_free_no_lock(szone_t *szone, large_entry_t *entries, unsigned num, vm_range_t *range_to_deallocate)
-{
-	size_t	size = num * sizeof(large_entry_t);
-
-	range_to_deallocate->address = (vm_address_t)entries;
-	range_to_deallocate->size = round_page_quanta(size);
-}
-
-static large_entry_t *
-large_entries_grow_no_lock(szone_t *szone, vm_range_t *range_to_deallocate)
-{
-	// sets range_to_deallocate
-	unsigned		old_num_entries = szone->num_large_entries;
-	large_entry_t	*old_entries = szone->large_entries;
-	// always an odd number for good hashing
-	unsigned		new_num_entries = (old_num_entries) ? old_num_entries * 2 + 1 :
-	((vm_page_quanta_size / sizeof(large_entry_t)) - 1);
-	large_entry_t	*new_entries = large_entries_alloc_no_lock(szone, new_num_entries);
-	unsigned		index = old_num_entries;
-	large_entry_t	oldRange;
-
-	// if the allocation of new entries failed, bail
-	if (new_entries == NULL)
-		return NULL;
-
-	szone->num_large_entries = new_num_entries;
-	szone->large_entries = new_entries;
-
-	/* rehash entries into the new list */
-	while (index--) {
-		oldRange = old_entries[index];
-		if (oldRange.address) {
-			large_entry_insert_no_lock(szone, oldRange);
-		}
-	}
-
-	if (old_entries) {
-		large_entries_free_no_lock(szone, old_entries, old_num_entries, range_to_deallocate);
-	} else {
-		range_to_deallocate->address = (vm_address_t)0;
-		range_to_deallocate->size = 0;
-	}
-
-	return new_entries;
-}
-
-// frees the specific entry in the size table
-// returns a range to truly deallocate
-static vm_range_t
-large_entry_free_no_lock(szone_t *szone, large_entry_t *entry)
-{
-	vm_range_t		range;
-
-	range.address = entry->address;
-	range.size = entry->size;
-
-	if (szone->debug_flags & SCALABLE_MALLOC_ADD_GUARD_PAGES) {
-		protect((void *)range.address, range.size, PROT_READ | PROT_WRITE, szone->debug_flags);
-		range.address -= vm_page_quanta_size;
-		range.size += 2 * vm_page_quanta_size;
-	}
-
-	entry->address = 0;
-	entry->size = 0;
-	entry->did_madvise_reusable = FALSE;
-	large_entries_rehash_after_entry_no_lock(szone, entry);
-
-#if DEBUG_MALLOC
-	if (large_entry_for_pointer_no_lock(szone, (void *)range.address)) {
-		malloc_printf("*** freed entry %p still in use; num_large_entries=%d\n",
-					  range.address, szone->num_large_entries);
-		large_debug_print(szone);
-		szone_sleep();
-	}
-#endif
-	return range;
-}
-
-static NOINLINE kern_return_t
-large_in_use_enumerator(task_t task, void *context, unsigned type_mask, vm_address_t large_entries_address,
-						unsigned num_entries, memory_reader_t reader, vm_range_recorder_t recorder)
-{
-	unsigned		index = 0;
-	vm_range_t		buffer[MAX_RECORDER_BUFFER];
-	unsigned		count = 0;
-	large_entry_t	*entries;
-	kern_return_t	err;
-	vm_range_t		range;
-	large_entry_t	entry;
-
-	err = reader(task, large_entries_address, sizeof(large_entry_t) * num_entries, (void **)&entries);
-	if (err)
-		return err;
-
-	index = num_entries;
-	if (type_mask & MALLOC_ADMIN_REGION_RANGE_TYPE) {
-		range.address = large_entries_address;
-		range.size = round_page_quanta(num_entries * sizeof(large_entry_t));
-		recorder(task, context, MALLOC_ADMIN_REGION_RANGE_TYPE, &range, 1);
-	}
-	if (type_mask & (MALLOC_PTR_IN_USE_RANGE_TYPE | MALLOC_PTR_REGION_RANGE_TYPE)) {
-		while (index--) {
-			entry = entries[index];
-			if (entry.address) {
-				range.address = entry.address;
-				range.size = entry.size;
-				buffer[count++] = range;
-				if (count >= MAX_RECORDER_BUFFER) {
-					recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE | MALLOC_PTR_REGION_RANGE_TYPE,
-							 buffer, count);
-					count = 0;
-				}
-			}
-		}
-	}
-	if (count) {
-		recorder(task, context, MALLOC_PTR_IN_USE_RANGE_TYPE | MALLOC_PTR_REGION_RANGE_TYPE,
-				 buffer, count);
-	}
-	return 0;
-}
-
-static void *
-large_malloc(szone_t *szone, size_t num_kernel_pages, unsigned char alignment,
-			 boolean_t cleared_requested)
-{
-	void		*addr;
-	vm_range_t		range_to_deallocate;
-	size_t		size;
-	large_entry_t	large_entry;
-
-	if (!num_kernel_pages)
-		num_kernel_pages = 1; // minimal allocation size for this szone
-	size = (size_t)num_kernel_pages << vm_page_quanta_shift;
-	range_to_deallocate.size = 0;
-	range_to_deallocate.address = 0;
-
-#if LARGE_CACHE
-	if (size < LARGE_CACHE_SIZE_ENTRY_LIMIT) { // Look for a large_entry_t on the death-row cache?
-		SZONE_LOCK(szone);
-
-		int i, best = -1, idx = szone->large_entry_cache_newest, stop_idx = szone->large_entry_cache_oldest;
-		size_t best_size = SIZE_T_MAX;
-
-		while (1) { // Scan large_entry_cache for best fit, starting with most recent entry
-			size_t this_size = szone->large_entry_cache[idx].size;
-			addr = (void *)szone->large_entry_cache[idx].address;
-
-			if (0 == alignment || 0 == (((uintptr_t) addr) & (((uintptr_t) 1 << alignment) - 1))) {
-				if (size == this_size) { // size match!
-					best = idx;
-					best_size = this_size;
-					break;
-				}
-
-				if (size <= this_size && this_size < best_size) { // improved fit?
-					best = idx;
-					best_size = this_size;
-				}
-			}
-
-			if (idx == stop_idx) // exhausted live ring?
-				break;
-
-			if (idx)
-				idx--; // bump idx down
-			else
-				idx = LARGE_ENTRY_CACHE_SIZE - 1; // wrap idx
-		}
-
-		if (best > -1 && (best_size - size) < size) { //limit fragmentation to 50%
-			addr = (void *)szone->large_entry_cache[best].address;
-			boolean_t was_madvised_reusable = szone->large_entry_cache[best].did_madvise_reusable;
-
-			// Compact live ring to fill entry now vacated at large_entry_cache[best]
-			// while preserving time-order
-			if (szone->large_entry_cache_oldest < szone->large_entry_cache_newest) {
-
-				// Ring hasn't wrapped. Fill in from right.
-				for (i = best; i < szone->large_entry_cache_newest; ++i)
-					szone->large_entry_cache[i] = szone->large_entry_cache[i + 1];
-
-				szone->large_entry_cache_newest--; // Pull in right endpoint.
-
-			} else if (szone->large_entry_cache_newest < szone->large_entry_cache_oldest) {
-
-				// Ring has wrapped. Arrange to fill in from the contiguous side.
-				if (best <= szone->large_entry_cache_newest) {
-					// Fill from right.
-					for (i = best; i < szone->large_entry_cache_newest; ++i)
-						szone->large_entry_cache[i] = szone->large_entry_cache[i + 1];
-
-					if (0 < szone->large_entry_cache_newest)
-						szone->large_entry_cache_newest--;
-					else
-						szone->large_entry_cache_newest = LARGE_ENTRY_CACHE_SIZE - 1;
-				} else {
-					// Fill from left.
-					for ( i = best; i > szone->large_entry_cache_oldest; --i)
-						szone->large_entry_cache[i] = szone->large_entry_cache[i - 1];
-
-					if (szone->large_entry_cache_oldest < LARGE_ENTRY_CACHE_SIZE - 1)
-						szone->large_entry_cache_oldest++;
-					else
-						szone->large_entry_cache_oldest = 0;
-				}
-
-			} else {
-				// By trichotomy, large_entry_cache_newest == large_entry_cache_oldest.
-				// That implies best == large_entry_cache_newest == large_entry_cache_oldest
-				// and the ring is now empty.
-				szone->large_entry_cache[best].address = 0;
-				szone->large_entry_cache[best].size = 0;
-				szone->large_entry_cache[best].did_madvise_reusable = FALSE;
-			}
-
-			if ((szone->num_large_objects_in_use + 1) * 4 > szone->num_large_entries) {
-				// density of hash table too high; grow table
-				// we do that under lock to avoid a race
-				large_entry_t *entries = large_entries_grow_no_lock(szone, &range_to_deallocate);
-				if (entries == NULL) {
-					SZONE_UNLOCK(szone);
-					return NULL;
-				}
-			}
-
-			large_entry.address = (vm_address_t)addr;
-			large_entry.size = best_size;
-			large_entry.did_madvise_reusable = FALSE;
-			large_entry_insert_no_lock(szone, large_entry);
-
-			szone->num_large_objects_in_use ++;
-			szone->num_bytes_in_large_objects += best_size;
-			if (!was_madvised_reusable)
-				szone->large_entry_cache_reserve_bytes -= best_size;
-
-			szone->large_entry_cache_bytes -= best_size;
-
-			if (szone->flotsam_enabled && szone->large_entry_cache_bytes < SZONE_FLOTSAM_THRESHOLD_LOW) {
-				szone->flotsam_enabled = FALSE;
-			}
-
-			SZONE_UNLOCK(szone);
-
-			if (range_to_deallocate.size) {
-				// we deallocate outside the lock
-				deallocate_pages(szone, (void *)range_to_deallocate.address, range_to_deallocate.size, 0);
-			}
-
-			// Perform the madvise() outside the lock.
-			// Typically the madvise() is successful and we'll quickly return from this routine.
-			// In the unusual case of failure, reacquire the lock to unwind.
-#if TARGET_OS_EMBEDDED
-			// Ok to do this madvise on embedded because we won't call MADV_FREE_REUSABLE on a large
-			// cache block twice without MADV_FREE_REUSE in between.
-#endif
-			if (was_madvised_reusable && -1 == madvise(addr, size, MADV_FREE_REUSE)) {
-				/* -1 return: VM map entry change makes this unfit for reuse. */
-#if DEBUG_MADVISE
-				szone_error(szone, 0, "large_malloc madvise(..., MADV_FREE_REUSE) failed",
-							addr, "length=%d\n", size);
-#endif
-
-				SZONE_LOCK(szone);
-				szone->num_large_objects_in_use--;
-				szone->num_bytes_in_large_objects -= large_entry.size;
-
-				// Re-acquire "entry" after interval just above where we let go the lock.
-				large_entry_t *entry = large_entry_for_pointer_no_lock(szone, addr);
-				if (NULL == entry) {
-					szone_error(szone, 1, "entry for pointer being discarded from death-row vanished", addr, NULL);
-					SZONE_UNLOCK(szone);
-				} else {
-
-					range_to_deallocate = large_entry_free_no_lock(szone, entry);
-					SZONE_UNLOCK(szone);
-
-					if (range_to_deallocate.size) {
-						// we deallocate outside the lock
-						deallocate_pages(szone, (void *)range_to_deallocate.address, range_to_deallocate.size, 0);
-					}
-				}
-				/* Fall through to allocate_pages() afresh. */
-			} else {
-				if (cleared_requested) {
-					memset(addr, 0, size);
-				}
-
-				return addr;
-			}
-		} else {
-			SZONE_UNLOCK(szone);
-		}
-	}
-
-	range_to_deallocate.size = 0;
-	range_to_deallocate.address = 0;
-#endif /* LARGE_CACHE */
-
-	addr = allocate_pages(szone, size, alignment, szone->debug_flags, VM_MEMORY_MALLOC_LARGE);
-	if (addr == NULL) {
-		return NULL;
-	}
-
-	SZONE_LOCK(szone);
-	if ((szone->num_large_objects_in_use + 1) * 4 > szone->num_large_entries) {
-		// density of hash table too high; grow table
-		// we do that under lock to avoid a race
-		large_entry_t *entries = large_entries_grow_no_lock(szone, &range_to_deallocate);
-		if (entries == NULL) {
-			SZONE_UNLOCK(szone);
-			return NULL;
-		}
-	}
-
-	large_entry.address = (vm_address_t)addr;
-	large_entry.size = size;
-	large_entry.did_madvise_reusable = FALSE;
-	large_entry_insert_no_lock(szone, large_entry);
-
-	szone->num_large_objects_in_use ++;
-	szone->num_bytes_in_large_objects += size;
-	SZONE_UNLOCK(szone);
-
-	if (range_to_deallocate.size) {
-		// we deallocate outside the lock
-		deallocate_pages(szone, (void *)range_to_deallocate.address, range_to_deallocate.size, 0);
-	}
-	return addr;
-}
-
-static NOINLINE void
-free_large(szone_t *szone, void *ptr)
-{
-	// We have established ptr is page-aligned and neither tiny nor small
-	large_entry_t	*entry;
-	vm_range_t		vm_range_to_deallocate;
-
-	SZONE_LOCK(szone);
-	entry = large_entry_for_pointer_no_lock(szone, ptr);
-	if (entry) {
-#if LARGE_CACHE
-		if (entry->size < LARGE_CACHE_SIZE_ENTRY_LIMIT &&
-			-1 != madvise((void *)(entry->address), entry->size, MADV_CAN_REUSE)) { // Put the large_entry_t on the death-row cache?
-			int idx = szone->large_entry_cache_newest, stop_idx = szone->large_entry_cache_oldest;
-			large_entry_t this_entry = *entry; // Make a local copy, "entry" is volatile when lock is let go.
-			boolean_t reusable = TRUE;
-			boolean_t should_madvise = szone->large_entry_cache_reserve_bytes + this_entry.size > szone->large_entry_cache_reserve_limit;
-
-			// Already freed?
-			// [Note that repeated entries in death-row risk vending the same entry subsequently
-			// to two different malloc() calls. By checking here the (illegal) double free
-			// is accommodated, matching the behavior of the previous implementation.]
-			while (1) { // Scan large_entry_cache starting with most recent entry
-				if (szone->large_entry_cache[idx].address == entry->address) {
-					szone_error(szone, 1, "pointer being freed already on death-row", ptr, NULL);
-					SZONE_UNLOCK(szone);
-					return;
-				}
-
-				if (idx == stop_idx) // exhausted live ring?
-					break;
-
-				if (idx)
-					idx--; // bump idx down
-				else
-					idx = LARGE_ENTRY_CACHE_SIZE - 1; // wrap idx
-			}
-
-			SZONE_UNLOCK(szone);
-
-			if (szone->debug_flags & SCALABLE_MALLOC_PURGEABLE) { // Are we a purgable zone?
-				int state = VM_PURGABLE_NONVOLATILE; // restore to default condition
-
-				if (KERN_SUCCESS != vm_purgable_control(mach_task_self(), this_entry.address, VM_PURGABLE_SET_STATE, &state)) {
-					malloc_printf("*** can't vm_purgable_control(..., VM_PURGABLE_SET_STATE) for large freed block at %p\n",
-								  this_entry.address);
-					reusable = FALSE;
-				}
-			}
-
-			if (szone->large_legacy_reset_mprotect) { // Linked for Leopard?
-				// Accomodate Leopard apps that (illegally) mprotect() their own guard pages on large malloc'd allocations
-				int err = mprotect((void *)(this_entry.address), this_entry.size, PROT_READ | PROT_WRITE);
-				if (err) {
-					malloc_printf("*** can't reset protection for large freed block at %p\n", this_entry.address);
-					reusable = FALSE;
-				}
-			}
-
-			// madvise(..., MADV_REUSABLE) death-row arrivals if hoarding would exceed large_entry_cache_reserve_limit
-			if (should_madvise) {
-				// Issue madvise to avoid paging out the dirtied free()'d pages in "entry"
-				MAGMALLOC_MADVFREEREGION((void *)szone, (void *)0, (void *)(this_entry.address), this_entry.size); // DTrace USDT Probe
-
-#if TARGET_OS_EMBEDDED
-				// Ok to do this madvise on embedded because we won't call MADV_FREE_REUSABLE on a large
-				// cache block twice without MADV_FREE_REUSE in between.
-#endif
-				if (-1 == madvise((void *)(this_entry.address), this_entry.size, MADV_FREE_REUSABLE)) {
-					/* -1 return: VM map entry change makes this unfit for reuse. */
-#if DEBUG_MADVISE
-					szone_error(szone, 0, "free_large madvise(..., MADV_FREE_REUSABLE) failed",
-								(void *)this_entry.address, "length=%d\n", this_entry.size);
-#endif
-					reusable = FALSE;
-				}
-			}
-
-			SZONE_LOCK(szone);
-
-			// Re-acquire "entry" after interval just above where we let go the lock.
-			entry = large_entry_for_pointer_no_lock(szone, ptr);
-			if (NULL == entry) {
-				szone_error(szone, 1, "entry for pointer being freed from death-row vanished", ptr, NULL);
-				SZONE_UNLOCK(szone);
-				return;
-			}
-
-			// Add "entry" to death-row ring
-			if (reusable) {
-				int idx = szone->large_entry_cache_newest; // Most recently occupied
-				vm_address_t addr;
-				size_t adjsize;
-
-				if (szone->large_entry_cache_newest == szone->large_entry_cache_oldest &&
-					0 == szone->large_entry_cache[idx].address) {
-					// Ring is empty, idx is good as it stands
-					addr = 0;
-					adjsize = 0;
-				} else {
-					// Extend the queue to the "right" by bumping up large_entry_cache_newest
-					if (idx == LARGE_ENTRY_CACHE_SIZE - 1)
-						idx = 0; // Wrap index
-					else
-						idx++; // Bump index
-
-					if (idx == szone->large_entry_cache_oldest) { // Fully occupied
-						// Drop this entry from the cache and deallocate the VM
-						addr = szone->large_entry_cache[idx].address;
-						adjsize = szone->large_entry_cache[idx].size;
-						szone->large_entry_cache_bytes -= adjsize;
-						if (!szone->large_entry_cache[idx].did_madvise_reusable)
-							szone->large_entry_cache_reserve_bytes -= adjsize;
-					} else {
-						// Using an unoccupied cache slot
-						addr = 0;
-						adjsize = 0;
-					}
-				}
-
-				if ((szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE))
-					memset((void *)(entry->address), should_madvise ? SCRUBBLE_BYTE : SCRABBLE_BYTE, entry->size);
-
-				entry->did_madvise_reusable = should_madvise; // Was madvise()'d above?
-				if (!should_madvise) // Entered on death-row without madvise() => up the hoard total
-					szone->large_entry_cache_reserve_bytes += entry->size;
-
-				szone->large_entry_cache_bytes += entry->size;
-
-				if (!szone->flotsam_enabled && szone->large_entry_cache_bytes > SZONE_FLOTSAM_THRESHOLD_HIGH) {
-					szone->flotsam_enabled = TRUE;
-				}
-
-				szone->large_entry_cache[idx] = *entry;
-				szone->large_entry_cache_newest = idx;
-
-				szone->num_large_objects_in_use--;
-				szone->num_bytes_in_large_objects -= entry->size;
-
-				(void)large_entry_free_no_lock(szone, entry);
-
-				if (0 == addr) {
-					SZONE_UNLOCK(szone);
-					return;
-				}
-
-				// Fall through to drop large_entry_cache_oldest from the cache,
-				// and then deallocate its pages.
-
-				// Trim the queue on the "left" by bumping up large_entry_cache_oldest
-				if (szone->large_entry_cache_oldest == LARGE_ENTRY_CACHE_SIZE - 1)
-					szone->large_entry_cache_oldest = 0;
-				else
-					szone->large_entry_cache_oldest++;
-
-				// we deallocate_pages, including guard pages, outside the lock
-				SZONE_UNLOCK(szone);
-				deallocate_pages(szone, (void *)addr, (size_t)adjsize, 0);
-				return;
-			} else {
-				/* fall through to discard an allocation that is not reusable */
-			}
-		}
-#endif /* LARGE_CACHE */
-
-		szone->num_large_objects_in_use--;
-		szone->num_bytes_in_large_objects -= entry->size;
-
-		vm_range_to_deallocate = large_entry_free_no_lock(szone, entry);
-	} else {
-#if DEBUG_MALLOC
-		large_debug_print(szone);
-#endif
-		szone_error(szone, 1, "pointer being freed was not allocated", ptr, NULL);
-		SZONE_UNLOCK(szone);
-		return;
-	}
-	SZONE_UNLOCK(szone); // we release the lock asap
-	CHECK(szone, __PRETTY_FUNCTION__);
-
-	// we deallocate_pages, including guard pages, outside the lock
-	if (vm_range_to_deallocate.address) {
-#if DEBUG_MALLOC
-		// FIXME: large_entry_for_pointer_no_lock() needs the lock held ...
-		if (large_entry_for_pointer_no_lock(szone, (void *)vm_range_to_deallocate.address)) {
-			malloc_printf("*** invariant broken: %p still in use num_large_entries=%d\n",
-						  vm_range_to_deallocate.address, szone->num_large_entries);
-			large_debug_print(szone);
-			szone_sleep();
-		}
-#endif
-		deallocate_pages(szone, (void *)vm_range_to_deallocate.address, (size_t)vm_range_to_deallocate.size, 0);
-	}
-}
-
-static INLINE void *
-large_try_shrink_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_good_size)
-{
-	size_t shrinkage = old_size - new_good_size;
-
-	if (shrinkage) {
-		SZONE_LOCK(szone);
-		/* contract existing large entry */
-		large_entry_t *large_entry = large_entry_for_pointer_no_lock(szone, ptr);
-		if (!large_entry) {
-			szone_error(szone, 1, "large entry reallocated is not properly in table", ptr, NULL);
-			SZONE_UNLOCK(szone);
-			return ptr;
-		}
-
-		large_entry->address = (vm_address_t)ptr;
-		large_entry->size = new_good_size;
-		szone->num_bytes_in_large_objects -= shrinkage;
-		SZONE_UNLOCK(szone); // we release the lock asap
-
-		deallocate_pages(szone, (void *)((uintptr_t)ptr + new_good_size), shrinkage, 0);
-	}
-	return ptr;
-}
-
-static INLINE int
-large_try_realloc_in_place(szone_t *szone, void *ptr, size_t old_size, size_t new_size)
-{
-	vm_address_t	addr = (vm_address_t)ptr + old_size;
-	large_entry_t	*large_entry;
-	kern_return_t	err;
-
-	SZONE_LOCK(szone);
-	large_entry = large_entry_for_pointer_no_lock(szone, (void *)addr);
-	SZONE_UNLOCK(szone);
-
-	if (large_entry) { // check if "addr = ptr + old_size" is already spoken for
-		return 0; // large pointer already exists in table - extension is not going to work
-	}
-
-	new_size = round_page_quanta(new_size);
-	/*
-	 * Ask for allocation at a specific address, and mark as realloc
-	 * to request coalescing with previous realloc'ed extensions.
-	 */
-	err = vm_allocate(mach_task_self(), &addr, new_size - old_size, VM_MAKE_TAG(VM_MEMORY_REALLOC));
-	if (err != KERN_SUCCESS) {
-		return 0;
-	}
-
-	SZONE_LOCK(szone);
-	/* extend existing large entry */
-	large_entry = large_entry_for_pointer_no_lock(szone, ptr);
-	if (!large_entry) {
-		szone_error(szone, 1, "large entry reallocated is not properly in table", ptr, NULL);
-		SZONE_UNLOCK(szone);
-		return 0; // Bail, leaking "addr"
-	}
-
-	large_entry->address = (vm_address_t)ptr;
-	large_entry->size = new_size;
-	szone->num_bytes_in_large_objects += new_size - old_size;
-	SZONE_UNLOCK(szone); // we release the lock asap
-
-	return 1;
-}
+#define LOG(szone, ptr) 0
+#endif
+
+// Maximum number of magazines, set from the number of logical CPUS and
+// possibly limited by the MallocMaxMagazines environment variable.
+int max_magazines;
+
+// Control whether medium is enabled at all when creating new magazine zones
+bool magazine_medium_enabled = true;
+
+// Control the DRAM limit at which medium kicks in.
+uint64_t magazine_medium_active_threshold = MEDIUM_ACTIVATION_THRESHOLD;
+
+// Control the DRAM limit at which the expanded large cache kicks in.
+uint64_t magazine_large_expanded_cache_threshold = LARGE_CACHE_EXPANDED_THRESHOLD;
+
+#if CONFIG_AGGRESSIVE_MADVISE
+bool aggressive_madvise_enabled = DEFAULT_AGGRESSIVE_MADVISE_ENABLED;
+#endif // CONFIG_AGGRESSIVE_MADVISE
+
+#if CONFIG_LARGE_CACHE
+bool large_cache_enabled = DEFAULT_LARGE_CACHE_ENABLED;
+#endif // CONFIG_LARGE_CACHE
+
+// <rdar://problem/47353961> Maximum number of magzines that the medium
+// allocator will use. This addresses a 32-bit load-offset range issue found
+// in some apps when introducing medium.
+int max_medium_magazines;
+
+// Number of regions to retain in a recirc depot.
+#if CONFIG_RECIRC_DEPOT
+int recirc_retained_regions = DEFAULT_RECIRC_RETAINED_REGIONS;
+#endif // CONFIG_RECIRC_DEPOT
 
 /*********************	Zone call backs	************************/
 /*
- * Mark these NOINLINE to avoid bloating the purgeable zone call backs
+ * Mark these MALLOC_NOINLINE to avoid bloating the purgeable zone call backs
  */
-static NOINLINE void
+void
 szone_free(szone_t *szone, void *ptr)
 {
-	region_t	tiny_region;
-	region_t	small_region;
+	region_t tiny_region;
+	region_t small_region;
 
 #if DEBUG_MALLOC
-	if (LOG(szone, ptr))
-		malloc_printf("in szone_free with %p\n", ptr);
-#endif
-	if (!ptr)
-		return;
+	if (LOG(szone, ptr)) {
+		malloc_report(ASL_LEVEL_INFO, "in szone_free with %p\n", ptr);
+	}
+#endif
+	if (!ptr) {
+		return;
+	}
 	/*
 	 * Try to free to a tiny region.
 	 */
 	if ((uintptr_t)ptr & (TINY_QUANTUM - 1)) {
-		szone_error(szone, 1, "Non-aligned pointer being freed", ptr, NULL);
-		return;
-	}
-	if ((tiny_region = tiny_region_for_ptr_no_lock(szone, ptr)) != NULL) {
+		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed\n", ptr);
+		return;
+	}
+	if ((tiny_region = tiny_region_for_ptr_no_lock(&szone->tiny_rack, ptr)) != NULL) {
 		if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS) {
-			szone_error(szone, 1, "Pointer to metadata being freed", ptr, NULL);
+			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed\n", ptr);
 			return;
 		}
-		free_tiny(szone, ptr, tiny_region, 0);
+		free_tiny(&szone->tiny_rack, ptr, tiny_region, 0, false);
 		return;
 	}
 
@@ -6164,55 +112,71 @@
 	 * Try to free to a small region.
 	 */
 	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1)) {
-		szone_error(szone, 1, "Non-aligned pointer being freed (2)", ptr, NULL);
-		return;
-	}
-	if ((small_region = small_region_for_ptr_no_lock(szone, ptr)) != NULL) {
+		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed (2)\n", ptr);
+		return;
+	}
+	if ((small_region = small_region_for_ptr_no_lock(&szone->small_rack, ptr)) != NULL) {
 		if (SMALL_META_INDEX_FOR_PTR(ptr) >= NUM_SMALL_BLOCKS) {
-			szone_error(szone, 1, "Pointer to metadata being freed (2)", ptr, NULL);
+			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed (2)\n", ptr);
 			return;
 		}
-		free_small(szone, ptr, small_region, 0);
-		return;
-	}
+		free_small(&szone->small_rack, ptr, small_region, 0);
+		return;
+	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	region_t medium_region;
+
+	if (szone->is_medium_engaged &&
+			(medium_region = medium_region_for_ptr_no_lock(&szone->medium_rack, ptr)) != NULL) {
+		if (MEDIUM_META_INDEX_FOR_PTR(ptr) >= NUM_MEDIUM_BLOCKS) {
+			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed (2)\n", ptr);
+			return;
+		}
+		free_medium(&szone->medium_rack, ptr, medium_region, 0);
+		return;
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
 
 	/* check that it's a legal large allocation */
 	if ((uintptr_t)ptr & (vm_page_quanta_size - 1)) {
-		szone_error(szone, 1, "non-page-aligned, non-allocated pointer being freed", ptr, NULL);
+		malloc_zone_error(szone->debug_flags, true, "non-page-aligned, non-allocated pointer %p being freed\n", ptr);
 		return;
 	}
 	free_large(szone, ptr);
 }
 
-static NOINLINE void
+void
 szone_free_definite_size(szone_t *szone, void *ptr, size_t size)
 {
 #if DEBUG_MALLOC
-	if (LOG(szone, ptr))
-		malloc_printf("in szone_free_definite_size with %p\n", ptr);
+	if (LOG(szone, ptr)) {
+		malloc_report(ASL_LEVEL_INFO, "in szone_free_definite_size with %p\n", ptr);
+	}
 
 	if (0 == size) {
-		szone_error(szone, 1, "pointer of size zero being freed", ptr, NULL);
-		return;
-	}
-
-#endif
-	if (!ptr)
-		return;
+		malloc_zone_error(szone->debug_flags, true, "pointer %p of size zero being freed\n", ptr);
+		return;
+	}
+
+#endif
+	if (!ptr) {
+		return;
+	}
 
 	/*
 	 * Try to free to a tiny region.
 	 */
 	if ((uintptr_t)ptr & (TINY_QUANTUM - 1)) {
-		szone_error(szone, 1, "Non-aligned pointer being freed", ptr, NULL);
-		return;
-	}
-	if (size <= (NUM_TINY_SLOTS - 1)*TINY_QUANTUM) {
+		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed\n", ptr);
+		return;
+	}
+	if (size <= TINY_LIMIT_THRESHOLD) {
 		if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS) {
-			szone_error(szone, 1, "Pointer to metadata being freed", ptr, NULL);
+			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed\n", ptr);
 			return;
 		}
-		free_tiny(szone, ptr, TINY_REGION_FOR_PTR(ptr), size);
+		free_tiny(&szone->tiny_rack, ptr, TINY_REGION_FOR_PTR(ptr), size, false);
 		return;
 	}
 
@@ -6220,124 +184,133 @@
 	 * Try to free to a small region.
 	 */
 	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1)) {
-		szone_error(szone, 1, "Non-aligned pointer being freed (2)", ptr, NULL);
-		return;
-	}
-	if (size <= szone->large_threshold) {
+		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed (2)\n", ptr);
+		return;
+	}
+	if (size <= SMALL_LIMIT_THRESHOLD) {
 		if (SMALL_META_INDEX_FOR_PTR(ptr) >= NUM_SMALL_BLOCKS) {
-			szone_error(szone, 1, "Pointer to metadata being freed (2)", ptr, NULL);
+			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed (2)\n", ptr);
 			return;
 		}
-		free_small(szone, ptr, SMALL_REGION_FOR_PTR(ptr), size);
-		return;
-	}
+		free_small(&szone->small_rack, ptr, SMALL_REGION_FOR_PTR(ptr), size);
+		return;
+	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	/*
+	 * Try to free to a medium region.
+	 */
+	if (szone->is_medium_engaged && size <= MEDIUM_LIMIT_THRESHOLD) {
+		if (MEDIUM_META_INDEX_FOR_PTR(ptr) >= NUM_MEDIUM_BLOCKS) {
+			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed (2)\n", ptr);
+			return;
+		}
+		free_medium(&szone->medium_rack, ptr, MEDIUM_REGION_FOR_PTR(ptr), size);
+		return;
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
 
 	/* check that it's a legal large allocation */
 	if ((uintptr_t)ptr & (vm_page_quanta_size - 1)) {
-		szone_error(szone, 1, "non-page-aligned, non-allocated pointer being freed", ptr, NULL);
+		malloc_zone_error(szone->debug_flags, true, "non-page-aligned, non-allocated pointer %p being freed\n", ptr);
 		return;
 	}
 	free_large(szone, ptr);
 }
 
-static NOINLINE void *
+MALLOC_NOINLINE void *
 szone_malloc_should_clear(szone_t *szone, size_t size, boolean_t cleared_requested)
 {
-	void	*ptr;
-	msize_t	msize;
-
-	if (size <= (NUM_TINY_SLOTS - 1)*TINY_QUANTUM) {
-		// think tiny
+	void *ptr;
+	msize_t msize;
+
+	if (size <= TINY_LIMIT_THRESHOLD) {
 		msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
-		if (!msize)
+		if (!msize) {
 			msize = 1;
-		ptr = tiny_malloc_should_clear(szone, msize, cleared_requested);
-	} else if (size <= szone->large_threshold) {
-		// think small
+		}
+		ptr = tiny_malloc_should_clear(&szone->tiny_rack, msize, cleared_requested);
+	} else if (size <= SMALL_LIMIT_THRESHOLD) {
 		msize = SMALL_MSIZE_FOR_BYTES(size + SMALL_QUANTUM - 1);
-		if (!msize)
+		if (!msize) {
 			msize = 1;
-		ptr = small_malloc_should_clear(szone, msize, cleared_requested);
+		}
+		ptr = small_malloc_should_clear(&szone->small_rack, msize, cleared_requested);
+#if CONFIG_MEDIUM_ALLOCATOR
+	} else if (szone->is_medium_engaged && size <= MEDIUM_LIMIT_THRESHOLD) {
+		msize = MEDIUM_MSIZE_FOR_BYTES(size + MEDIUM_QUANTUM - 1);
+		if (!msize) {
+			msize = 1;
+		}
+		ptr = medium_malloc_should_clear(&szone->medium_rack, msize, cleared_requested);
+#endif
 	} else {
-		// large
-		size_t num_kernel_pages = round_page_quanta(size) >> vm_page_quanta_shift;
-		if (num_kernel_pages == 0)	/* Overflowed */
+		size_t num_kernel_pages = round_large_page_quanta(size) >> large_vm_page_quanta_shift;
+		if (num_kernel_pages == 0) { /* Overflowed */
 			ptr = 0;
-		else
+		} else {
 			ptr = large_malloc(szone, num_kernel_pages, 0, cleared_requested);
+		}
 	}
 #if DEBUG_MALLOC
-	if (LOG(szone, ptr))
-		malloc_printf("szone_malloc returned %p\n", ptr);
+	if (LOG(szone, ptr)) {
+		malloc_report(ASL_LEVEL_INFO, "szone_malloc returned %p\n", ptr);
+	}
 #endif
 	/*
 	 * If requested, scribble on allocated memory.
 	 */
-	if ((szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE) && ptr && !cleared_requested && size)
+	if ((szone->debug_flags & MALLOC_DO_SCRIBBLE) && ptr && !cleared_requested && size) {
 		memset(ptr, SCRIBBLE_BYTE, szone_size(szone, ptr));
+	}
 
 	return ptr;
 }
 
-static NOINLINE void *
-szone_malloc(szone_t *szone, size_t size) {
+void *
+szone_malloc(szone_t *szone, size_t size)
+{
 	return szone_malloc_should_clear(szone, size, 0);
 }
 
-static NOINLINE void *
+void *
 szone_calloc(szone_t *szone, size_t num_items, size_t size)
 {
-	size_t total_bytes = num_items * size;
-
-	// Check for overflow of integer multiplication
-	if (num_items > 1) {
-#if __LP64__ /* size_t is uint64_t */
-		if ((num_items | size) & 0xffffffff00000000ul) {
-			// num_items or size equals or exceeds sqrt(2^64) == 2^32, appeal to wider arithmetic
-			__uint128_t product = ((__uint128_t)num_items) * ((__uint128_t)size);
-			if ((uint64_t)(product >> 64)) // compiles to test on upper register of register pair
-				return NULL;
-		}
-#else /* size_t is uint32_t */
-		if ((num_items | size) & 0xffff0000ul) {
-			// num_items or size equals or exceeds sqrt(2^32) == 2^16, appeal to wider arithmetic
-			uint64_t product = ((uint64_t)num_items) * ((uint64_t)size);
-			if ((uint32_t)(product >> 32)) // compiles to test on upper register of register pair
-				return NULL;
-		}
-#endif
-	}
-
+	size_t total_bytes;
+	if (calloc_get_size(num_items, size, 0, &total_bytes)) {
+		return NULL;
+	}
 	return szone_malloc_should_clear(szone, total_bytes, 1);
 }
 
-static NOINLINE void *
+void *
 szone_valloc(szone_t *szone, size_t size)
 {
-	void	*ptr;
-
-	if (size <= szone->large_threshold) {
+	void *ptr;
+
+	if (size <= MEDIUM_LIMIT_THRESHOLD) {
 		ptr = szone_memalign(szone, vm_page_quanta_size, size);
 	} else {
-		size_t	num_kernel_pages;
-
-		num_kernel_pages = round_page_quanta(size) >> vm_page_quanta_shift;
+		size_t num_kernel_pages;
+
+		num_kernel_pages = round_large_page_quanta(size) >> large_vm_page_quanta_shift;
 		ptr = large_malloc(szone, num_kernel_pages, 0, 0);
 	}
 
 #if DEBUG_MALLOC
-	if (LOG(szone, ptr))
-		malloc_printf("szone_valloc returned %p\n", ptr);
+	if (LOG(szone, ptr)) {
+		malloc_report(ASL_LEVEL_INFO, "szone_valloc returned %p\n", ptr);
+	}
 #endif
 	return ptr;
 }
 
 /* Isolate PIC-base load here. */
-static NOINLINE size_t
+size_t
 szone_size_try_large(szone_t *szone, const void *ptr)
 {
-	size_t		size = 0;
-	large_entry_t	*entry;
+	size_t size = 0;
+	large_entry_t *entry;
 
 	SZONE_LOCK(szone);
 	entry = large_entry_for_pointer_no_lock(szone, ptr);
@@ -6347,95 +320,68 @@
 	SZONE_UNLOCK(szone);
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_printf("szone_size for %p returned %d\n", ptr, (unsigned)size);
+		malloc_report(ASL_LEVEL_INFO, "szone_size for %p returned %d\n", ptr, (unsigned)size);
 	}
 #endif
 	return size;
 }
 
-static NOINLINE size_t
+size_t
 szone_size(szone_t *szone, const void *ptr)
 {
-	boolean_t		is_free;
-	msize_t		msize, msize_and_free;
-
-	if (!ptr)
+	size_t sz = 0;
+
+	if (!ptr) {
 		return 0;
+	}
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_printf("in szone_size for %p (szone=%p)\n", ptr, szone);
+		malloc_report(ASL_LEVEL_INFO, "in szone_size for %p (szone=%p)\n", ptr, szone);
 	}
 #endif
 
 	/*
 	 * Look for it in a tiny region.
 	 */
-	if ((uintptr_t)ptr & (TINY_QUANTUM - 1))
+	if ((uintptr_t)ptr & (TINY_QUANTUM - 1)) {
 		return 0;
-	if (tiny_region_for_ptr_no_lock(szone, ptr)) {
-		if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS)
-			return 0;
-		msize = get_tiny_meta_header(ptr, &is_free);
-		if (is_free)
-			return 0;
-#if TINY_CACHE
-		{
-			mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr));
-			if (DEPOT_MAGAZINE_INDEX != mag_index) {
-				magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-
-				if (msize < TINY_QUANTUM && ptr == (void *)((uintptr_t)(tiny_mag_ptr->mag_last_free) & ~ (TINY_QUANTUM - 1)))
-					return 0;
-			} else {
-				for (mag_index = 0; mag_index < szone->num_tiny_magazines; mag_index++) {
-					magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-
-					if (msize < TINY_QUANTUM && ptr == (void *)((uintptr_t)(tiny_mag_ptr->mag_last_free) & ~ (TINY_QUANTUM - 1)))
-						return 0;
-				}
-			}
-		}
-#endif
-		return TINY_BYTES_FOR_MSIZE(msize);
+	}
+
+	sz = tiny_size(&szone->tiny_rack, ptr);
+	if (sz) {
+		return sz;
 	}
 
 	/*
 	 * Look for it in a small region.
 	 */
-	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1))
+	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1)) {
 		return 0;
-	if (small_region_for_ptr_no_lock(szone, ptr)) {
-		if (SMALL_META_INDEX_FOR_PTR(ptr) >= NUM_SMALL_BLOCKS)
-			return 0;
-		msize_and_free = *SMALL_METADATA_FOR_PTR(ptr);
-		if (msize_and_free & SMALL_IS_FREE)
-			return 0;
-#if SMALL_CACHE
-		{
-			mag_index_t	mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(ptr));
-			if (DEPOT_MAGAZINE_INDEX != mag_index) {
-				magazine_t	*small_mag_ptr = &(szone->small_magazines[mag_index]);
-
-				if (ptr == (void *)((uintptr_t)(small_mag_ptr->mag_last_free) & ~ (SMALL_QUANTUM - 1)))
-					return 0;
-			} else {
-				for (mag_index = 0; mag_index < szone->num_small_magazines; mag_index++) {
-					magazine_t	*small_mag_ptr = &(szone->small_magazines[mag_index]);
-
-					if (ptr == (void *)((uintptr_t)(small_mag_ptr->mag_last_free) & ~ (SMALL_QUANTUM - 1)))
-						return 0;
-				}
-			}
-		}
-#endif
-		return SMALL_BYTES_FOR_MSIZE(msize_and_free);
-	}
+	}
+
+	sz = small_size(&szone->small_rack, ptr);
+	if (sz) {
+		return sz;
+	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	/*
+	 * Look for it in a medium region.
+	 */
+	if (szone->is_medium_engaged) {
+		sz = medium_size(&szone->medium_rack, ptr);
+		if (sz) {
+			return sz;
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
 
 	/*
 	 * If not page-aligned, it cannot have come from a large allocation.
 	 */
-	if ((uintptr_t)ptr & (vm_page_quanta_size - 1))
+	if ((uintptr_t)ptr & (vm_page_quanta_size - 1)) {
 		return 0;
+	}
 
 	/*
 	 * Look for it in a large entry.
@@ -6443,15 +389,15 @@
 	return szone_size_try_large(szone, ptr);
 }
 
-static NOINLINE void *
+void *
 szone_realloc(szone_t *szone, void *ptr, size_t new_size)
 {
-	size_t	old_size, new_good_size, valid_size;
-	void	*new_ptr;
+	size_t old_size, new_good_size, valid_size;
+	void *new_ptr;
 
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_printf("in szone_realloc for %p, %d\n", ptr, (unsigned)new_size);
+		malloc_report(ASL_LEVEL_INFO, "in szone_realloc for %p, %d\n", ptr, (unsigned)new_size);
 	}
 #endif
 	if (NULL == ptr) {
@@ -6467,7 +413,7 @@
 
 	old_size = szone_size(szone, ptr);
 	if (!old_size) {
-		szone_error(szone, 1, "pointer being reallocated was not allocated", ptr, NULL);
+		malloc_zone_error(szone->debug_flags, true, "pointer %p being reallocated was not allocated\n", ptr);
 		return NULL;
 	}
 
@@ -6480,24 +426,26 @@
 	 * If the new size suits the tiny allocator and the pointer being resized
 	 * belongs to a tiny region, try to reallocate in-place.
 	 */
-	if (new_good_size <= (NUM_TINY_SLOTS - 1) * TINY_QUANTUM) {
-		if (old_size <= (NUM_TINY_SLOTS - 1) * TINY_QUANTUM) {
+	if (new_good_size <= TINY_LIMIT_THRESHOLD) {
+		if (old_size <= TINY_LIMIT_THRESHOLD) {
 			if (new_good_size <= (old_size >> 1)) {
 				/*
 				 * Serious shrinkage (more than half). free() the excess.
 				 */
-				return tiny_try_shrink_in_place(szone, ptr, old_size, new_good_size);
+				return tiny_try_shrink_in_place(&szone->tiny_rack, ptr, old_size, new_good_size);
 			} else if (new_good_size <= old_size) {
 				/*
 				 * new_good_size smaller than old_size but not by much (less than half).
 				 * Avoid thrashing at the expense of some wasted storage.
 				 */
-				if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+				if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 					memset(ptr + new_size, SCRIBBLE_BYTE, old_size - new_size);
+				}
 				return ptr;
-			} else if (tiny_try_realloc_in_place(szone, ptr, old_size, new_good_size)) { // try to grow the allocation
-				if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+			} else if (tiny_try_realloc_in_place(&szone->tiny_rack, ptr, old_size, new_good_size)) { // try to grow the allocation
+				if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 					memset(ptr + old_size, SCRIBBLE_BYTE, new_good_size - old_size);
+				}
 				return ptr;
 			}
 		}
@@ -6507,35 +455,57 @@
 		 * belongs to a small region, and we're not protecting the small allocations
 		 * try to reallocate in-place.
 		 */
-	} else if (new_good_size <= szone->large_threshold) {
-		if ((NUM_TINY_SLOTS - 1) * TINY_QUANTUM < old_size && old_size <= szone->large_threshold) {
+	} else if (new_good_size <= SMALL_LIMIT_THRESHOLD) {
+		if (TINY_LIMIT_THRESHOLD < old_size && old_size <= SMALL_LIMIT_THRESHOLD) {
 			if (new_good_size <= (old_size >> 1)) {
-				return small_try_shrink_in_place(szone, ptr, old_size, new_good_size);
+				return small_try_shrink_in_place(&szone->small_rack, ptr, old_size, new_good_size);
 			} else if (new_good_size <= old_size) {
-				if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+				if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 					memset(ptr + new_size, SCRIBBLE_BYTE, old_size - new_size);
+				}
 				return ptr;
-			} else if (small_try_realloc_in_place(szone, ptr, old_size, new_good_size)) {
-				if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+			} else if (small_try_realloc_in_place(&szone->small_rack, ptr, old_size, new_good_size)) {
+				if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 					memset(ptr + old_size, SCRIBBLE_BYTE, new_good_size - old_size);
+				}
 				return ptr;
 			}
 		}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	} else if (szone->is_medium_engaged && new_good_size <= MEDIUM_LIMIT_THRESHOLD) {
+		if (SMALL_LIMIT_THRESHOLD < old_size && old_size <= MEDIUM_LIMIT_THRESHOLD) {
+			if (new_good_size <= (old_size >> 1)) {
+				return medium_try_shrink_in_place(&szone->medium_rack, ptr, old_size, new_good_size);
+			} else if (new_good_size <= old_size) {
+				if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
+					memset(ptr + new_size, SCRIBBLE_BYTE, old_size - new_size);
+				}
+			} else if (medium_try_realloc_in_place(&szone->medium_rack, ptr, old_size, new_good_size)) {
+				if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
+					memset(ptr + old_size, SCRIBBLE_BYTE, new_good_size - old_size);
+				}
+				return ptr;
+			}
+		}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
 		/*
 		 * Else if the allocation's a large allocation, try to reallocate in-place there.
 		 */
-	} else if (!(szone->debug_flags & SCALABLE_MALLOC_PURGEABLE) && // purgeable needs fresh allocation
-			   (old_size > szone->large_threshold) &&
-			   (new_good_size > szone->large_threshold)) {
+	} else if (!(szone->debug_flags & MALLOC_PURGEABLE) && // purgeable needs fresh allocation
+			   (old_size > LARGE_THRESHOLD(szone)) && (new_good_size > LARGE_THRESHOLD(szone))) {
 		if (new_good_size <= (old_size >> 1)) {
 			return large_try_shrink_in_place(szone, ptr, old_size, new_good_size);
 		} else if (new_good_size <= old_size) {
-			if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+			if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 				memset(ptr + new_size, SCRIBBLE_BYTE, old_size - new_size);
+			}
 			return ptr;
 		} else if (large_try_realloc_in_place(szone, ptr, old_size, new_good_size)) {
-			if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+			if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 				memset(ptr + old_size, SCRIBBLE_BYTE, new_good_size - old_size);
+			}
 			return ptr;
 		}
 	}
@@ -6546,290 +516,140 @@
 	if (new_good_size <= (old_size >> 1)) {
 		/* Serious shrinkage (more than half). FALL THROUGH to alloc/copy/free. */
 	} else if (new_good_size <= old_size) {
-		if (szone->debug_flags & SCALABLE_MALLOC_DO_SCRIBBLE)
+		if (szone->debug_flags & MALLOC_DO_SCRIBBLE) {
 			memset(ptr + new_size, SCRIBBLE_BYTE, old_size - new_size);
+		}
 		return ptr;
 	}
 
 	new_ptr = szone_malloc(szone, new_size);
-	if (new_ptr == NULL)
+	if (new_ptr == NULL) {
 		return NULL;
+	}
 
 	/*
 	 * If the allocation's large enough, try to copy using VM.  If that fails, or
 	 * if it's too small, just copy by hand.
 	 */
 	valid_size = MIN(old_size, new_size);
-	if ((valid_size < szone->vm_copy_threshold) ||
-		vm_copy(mach_task_self(), (vm_address_t)ptr, valid_size, (vm_address_t)new_ptr))
+#if CONFIG_REALLOC_CAN_USE_VMCOPY
+	if ((valid_size <= VM_COPY_THRESHOLD) ||
+			vm_copy(mach_task_self(), (vm_address_t)ptr, valid_size, (vm_address_t)new_ptr))
+#endif
+	{
 		memcpy(new_ptr, ptr, valid_size);
+	}
 	szone_free(szone, ptr);
 
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_printf("szone_realloc returned %p for %d\n", new_ptr, (unsigned)new_size);
+		malloc_report(ASL_LEVEL_INFO, "szone_realloc returned %p for %d\n", new_ptr, (unsigned)new_size);
 	}
 #endif
 	return new_ptr;
 }
 
-static NOINLINE void *
+void *
 szone_memalign(szone_t *szone, size_t alignment, size_t size)
 {
-	if (size == 0)
+	if (size == 0) {
 		size = 1; // Ensures we'll return an aligned free()-able pointer
-
-	if ((size + alignment) < size) // size_t arithmetic wrapped!
+	}
+	if ((size + alignment) < size) { // size_t arithmetic wrapped!
 		return NULL;
-
-	// alignment is gauranteed a power of 2 at least as large as sizeof(void *), hence non-zero.
-	// Since size + alignment didn't wrap, 0 <= size + alignment - 1 < size + alignment
+	}
+
+	// alignment is a power of 2 at least as large as sizeof(void *), hence
+	// non-zero.  Since size + alignment didn't wrap, 0 <= size + alignment - 1
+	// < size + alignment
 	size_t span = size + alignment - 1;
 
 	if (alignment <= TINY_QUANTUM) {
-		return szone_malloc(szone, size); // Trivially satisfied by tiny, small, or large
-
-	} else if (span <= (NUM_TINY_SLOTS - 1)*TINY_QUANTUM) {
-		msize_t mspan = TINY_MSIZE_FOR_BYTES(span + TINY_QUANTUM - 1);
-		void *p = szone_malloc(szone, span); // avoids inlining tiny_malloc_should_clear(szone, mspan, 0);
-
-		if (NULL == p)
-			return NULL;
-
-		size_t offset = ((uintptr_t) p) & (alignment - 1); // p % alignment
-		size_t pad = (0 == offset) ? 0 : alignment - offset; // p + pad achieves desired alignment
-
-		msize_t msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
-		msize_t mpad = TINY_MSIZE_FOR_BYTES(pad + TINY_QUANTUM - 1);
-		msize_t mwaste = mspan - msize - mpad; // excess blocks
-
-		if (mpad > 0) {
-			void *q = (void *)(((uintptr_t) p) + pad);
-
-			// Mark q as a block header and in-use, thus creating two blocks.
-			magazine_t	*tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines,
-																		 REGION_TRAILER_FOR_TINY_REGION(TINY_REGION_FOR_PTR(p)),
-																		 MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(p)));
-			set_tiny_meta_header_in_use(q, msize);
-			tiny_mag_ptr->mag_num_objects++;
-
-			// set_tiny_meta_header_in_use() "reaffirms" the block_header on the *following* block, so
-			// now set its in_use bit as well. But only if its within the original allocation made above.
-			if (mwaste > 0)
-				BITARRAY_SET(TINY_INUSE_FOR_HEADER(TINY_BLOCK_HEADER_FOR_PTR(q)), TINY_INDEX_FOR_PTR(q) + msize);
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-
-			// Give up mpad blocks beginning at p to the tiny free list
-			// region_t r = TINY_REGION_FOR_PTR(p);
-			szone_free(szone, p); // avoids inlining free_tiny(szone, p, &r);
-
-			p = q; // advance p to the desired alignment
-		}
-
-		if (mwaste > 0) {
-			void *q = (void *)(((uintptr_t) p) + TINY_BYTES_FOR_MSIZE(msize));
-			// Mark q as block header and in-use, thus creating two blocks.
-			magazine_t	*tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines,
-																		 REGION_TRAILER_FOR_TINY_REGION(TINY_REGION_FOR_PTR(p)),
-																		 MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(p)));
-			set_tiny_meta_header_in_use(q, mwaste);
-			tiny_mag_ptr->mag_num_objects++;
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-
-			// Give up mwaste blocks beginning at q to the tiny free list
-			// region_t r = TINY_REGION_FOR_PTR(q);
-			szone_free(szone, q); // avoids inlining free_tiny(szone, q, &r);
-		}
-
-		return p; // p has the desired size and alignment, and can later be free()'d
-
-	} else if ((NUM_TINY_SLOTS - 1)*TINY_QUANTUM < size && alignment <= SMALL_QUANTUM) {
-		return szone_malloc(szone, size); // Trivially satisfied by small or large
-
-	} else if (span <= szone->large_threshold) {
-
-		if (size <= (NUM_TINY_SLOTS - 1)*TINY_QUANTUM) {
-			size = (NUM_TINY_SLOTS - 1)*TINY_QUANTUM + TINY_QUANTUM; // ensure block allocated by small does not have a tiny-possible size
+		// Trivially satisfied by tiny, small, medium, or large.
+		return szone_malloc(szone, size);
+	}
+	if (span <= TINY_LIMIT_THRESHOLD) {
+		return tiny_memalign(szone, alignment, size, span);
+	}
+	if (TINY_LIMIT_THRESHOLD < size && alignment <= SMALL_QUANTUM) {
+		// Trivially satisfied by small, medium or large.
+		return szone_malloc(szone, size);
+	}
+	if (size <= TINY_LIMIT_THRESHOLD) {
+		// The allocation asked for a size that TINY would normally fulfill
+		// but it cannot guarantee the alignment. So bump it up to fit inside
+		// SMALL and try again.
+		size = TINY_LIMIT_THRESHOLD + TINY_QUANTUM;
+		span = size + alignment - 1;
+	}
+	if (span <= SMALL_LIMIT_THRESHOLD) {
+		return small_memalign(szone, alignment, size, span);
+	}
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		if (size <= SMALL_LIMIT_THRESHOLD) {
+			size = SMALL_LIMIT_THRESHOLD + SMALL_QUANTUM;
 			span = size + alignment - 1;
 		}
-
-		msize_t mspan = SMALL_MSIZE_FOR_BYTES(span + SMALL_QUANTUM - 1);
-		void *p = szone_malloc(szone, span); // avoid inlining small_malloc_should_clear(szone, mspan, 0);
-
-		if (NULL == p)
-			return NULL;
-
-		size_t offset = ((uintptr_t) p) & (alignment - 1); // p % alignment
-		size_t pad = (0 == offset) ? 0 : alignment - offset; // p + pad achieves desired alignment
-
-		msize_t msize = SMALL_MSIZE_FOR_BYTES(size + SMALL_QUANTUM - 1);
-		msize_t mpad = SMALL_MSIZE_FOR_BYTES(pad + SMALL_QUANTUM - 1);
-		msize_t mwaste = mspan - msize - mpad; // excess blocks
-
-		if (mpad > 0) {
-			void *q = (void *)(((uintptr_t) p) + pad);
-
-			// Mark q as block header and in-use, thus creating two blocks.
-			magazine_t	*small_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->small_magazines,
-																		  REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)),
-																		  MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)));
-			small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(p), SMALL_META_INDEX_FOR_PTR(p), mpad);
-			small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(q), SMALL_META_INDEX_FOR_PTR(q), msize + mwaste);
-			small_mag_ptr->mag_num_objects++;
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-
-			// Give up mpad blocks beginning at p to the small free list
-			// region_t r = SMALL_REGION_FOR_PTR(p);
-			szone_free(szone, p); // avoid inlining free_small(szone, p, &r);
-
-			p = q; // advance p to the desired alignment
-		}
-		if (mwaste > 0) {
-			void *q = (void *)(((uintptr_t) p) + SMALL_BYTES_FOR_MSIZE(msize));
-			// Mark q as block header and in-use, thus creating two blocks.
-			magazine_t	*small_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->small_magazines,
-																		  REGION_TRAILER_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)),
-																		  MAGAZINE_INDEX_FOR_SMALL_REGION(SMALL_REGION_FOR_PTR(p)));
-			small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(p), SMALL_META_INDEX_FOR_PTR(p), msize);
-			small_meta_header_set_in_use(SMALL_META_HEADER_FOR_PTR(q), SMALL_META_INDEX_FOR_PTR(q), mwaste);
-			small_mag_ptr->mag_num_objects++;
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-
-			// Give up mwaste blocks beginning at q to the small free list
-			// region_t r = SMALL_REGION_FOR_PTR(q);
-			szone_free(szone, q); // avoid inlining free_small(szone, q, &r);
-		}
-
-		return p; // p has the desired size and alignment, and can later be free()'d
-
-	} else if (szone->large_threshold < size && alignment <= vm_page_quanta_size) {
-		return szone_malloc(szone, size); // Trivially satisfied by large
-
+		if (szone->is_medium_engaged && span <= MEDIUM_LIMIT_THRESHOLD) {
+			return medium_memalign(szone, alignment, size, span);
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+	if (LARGE_THRESHOLD(szone) < size && alignment <= vm_page_quanta_size) {
+		// Trivially satisfied by large (which rounds to a whole page).
+		return szone_malloc(szone, size);
+	}
+	// ensure block allocated by large does not have a small-possible size
+	size_t num_kernel_pages = round_large_page_quanta(MAX(LARGE_THRESHOLD(szone) + 1,
+			size)) >> large_vm_page_quanta_shift;
+	if (num_kernel_pages == 0) { /* Overflowed */
+		return NULL;
 	} else {
-		// ensure block allocated by large does not have a small-possible size
-		size_t num_kernel_pages = round_page_quanta(MAX(szone->large_threshold + 1, size)) >> vm_page_quanta_shift;
-		void *p;
-
-		if (num_kernel_pages == 0)	/* Overflowed */
-			p = NULL;
-		else
-			p = large_malloc(szone, num_kernel_pages, MAX(vm_page_quanta_shift, __builtin_ctz(alignment)), 0);
-
-		return p;
+		return large_malloc(szone, num_kernel_pages,
+				MAX(vm_page_quanta_shift, __builtin_ctz((unsigned)alignment)), 0);
 	}
 	/* NOTREACHED */
-}
-
-// given a size, returns the number of pointers allocated capable of holding
+	__builtin_unreachable();
+}
+
+// Given a size, returns the number of pointers allocated capable of holding
 // that size, up to the limit specified by the 'count' argument.  These pointers
 // are stored in the 'results' array, which must be allocated by the caller.
-// may return zero, since this function is only a best attempt at allocating
-// the pointers.  clients should be prepared to call malloc for any additional
+// May return zero, since this function is only a best attempt at allocating
+// the pointers. Clients should be prepared to call malloc for any additional
 // blocks they need.
-static NOINLINE unsigned
+unsigned
 szone_batch_malloc(szone_t *szone, size_t size, void **results, unsigned count)
 {
-	msize_t	msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
-	unsigned	found = 0;
-	mag_index_t	mag_index = mag_get_thread_index(szone);
-	magazine_t	*tiny_mag_ptr = &(szone->tiny_magazines[mag_index]);
-
 	// only bother implementing this for tiny
-	if (size > (NUM_TINY_SLOTS - 1)*TINY_QUANTUM)
-		return 0;
-	// make sure to return objects at least one quantum in size
-	if (!msize)
-		msize = 1;
-
-	CHECK(szone, __PRETTY_FUNCTION__);
-
-	// We must lock the zone now, since tiny_malloc_from_free_list assumes that
-	// the caller has done so.
-	SZONE_MAGAZINE_PTR_LOCK(szone, tiny_mag_ptr);
-
-	// with the zone locked, allocate objects from the free list until all
-	// sufficiently large objects have been exhausted, or we have met our quota
-	// of objects to allocate.
-	while (found < count) {
-		void *ptr = tiny_malloc_from_free_list(szone, tiny_mag_ptr, mag_index, msize);
-		if (!ptr)
-			break;
-
-		*results++ = ptr;
-		found++;
-	}
-	SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-	return found;
-}
-
-/* Try caching the tiny_region and checking if the next ptr hits there. */
-static NOINLINE void
+	if (size <= TINY_LIMIT_THRESHOLD) {
+		return tiny_batch_malloc(szone, size, results, count);
+	}
+	return 0;
+}
+
+void
 szone_batch_free(szone_t *szone, void **to_be_freed, unsigned count)
 {
-	unsigned	cc = 0;
-	void	*ptr;
-	region_t	tiny_region = NULL;
-	boolean_t	is_free;
-	msize_t	msize;
-	magazine_t	*tiny_mag_ptr = NULL;
-	mag_index_t mag_index = -1;
-
 	// frees all the pointers in to_be_freed
 	// note that to_be_freed may be overwritten during the process
-	if (!count)
-		return;
+	if (!count) {
+		return;
+	}
 
 	CHECK(szone, __PRETTY_FUNCTION__);
-	while (cc < count) {
-		ptr = to_be_freed[cc];
-		if (ptr) {
-			if (NULL == tiny_region || tiny_region != TINY_REGION_FOR_PTR(ptr)) { // region same as last iteration?
-				if (tiny_mag_ptr) { // non-NULL iff magazine lock taken
-					SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-					tiny_mag_ptr = NULL;
-				}
-
-				tiny_region = tiny_region_for_ptr_no_lock(szone, ptr);
-
-				if (tiny_region) {
-					tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines,
-																	REGION_TRAILER_FOR_TINY_REGION(tiny_region),
-																	MAGAZINE_INDEX_FOR_TINY_REGION(tiny_region));
-					mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(tiny_region);
-				}
-			}
-			if (tiny_region) {
-				// this is a tiny pointer
-				if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS)
-					break; // pointer to metadata; let the standard free deal with it
-				msize = get_tiny_meta_header(ptr, &is_free);
-				if (is_free)
-					break; // a double free; let the standard free deal with it
-
-				if (!tiny_free_no_lock(szone, tiny_mag_ptr, mag_index, tiny_region, ptr, msize)) {
-					// Arrange to re-acquire magazine lock
-					tiny_mag_ptr = NULL;
-					tiny_region = NULL;
-				}
-				to_be_freed[cc] = NULL;
-			} else {
-				// No region in this zone claims ptr; let the standard free deal with it
-				break;
-			}
-		}
-		cc++;
-	}
-
-	if (tiny_mag_ptr) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-		tiny_mag_ptr = NULL;
-	}
+
+	// We only support batch malloc in tiny. Let it free all of the pointers
+	// that belong to it, then let the standard free deal with the rest.
+	tiny_batch_free(szone, to_be_freed, count);
 
 	CHECK(szone, __PRETTY_FUNCTION__);
 	while (count--) {
-		ptr = to_be_freed[count];
-		if (ptr)
+		void *ptr = to_be_freed[count];
+		if (ptr) {
 			szone_free(szone, ptr);
+		}
 	}
 }
 
@@ -6837,37 +657,41 @@
 static void
 szone_destroy(szone_t *szone)
 {
-	size_t		index;
-	large_entry_t	*large;
-	vm_range_t		range_to_deallocate;
-
-#if LARGE_CACHE
-	SZONE_LOCK(szone);
-
-	/* disable any memory pressure responder */
-	szone->flotsam_enabled = FALSE;
-
-	// stack allocated copy of the death-row cache
-	int idx = szone->large_entry_cache_oldest, idx_max = szone->large_entry_cache_newest;
-	large_entry_t local_entry_cache[LARGE_ENTRY_CACHE_SIZE];
-
-	memcpy((void *)local_entry_cache, (void *)szone->large_entry_cache, sizeof(local_entry_cache));
-
-	szone->large_entry_cache_oldest = szone->large_entry_cache_newest = 0;
-	szone->large_entry_cache[0].address = 0x0;
-	szone->large_entry_cache[0].size = 0;
-	szone->large_entry_cache_bytes = 0;
-	szone->large_entry_cache_reserve_bytes = 0;
-
-	SZONE_UNLOCK(szone);
-
-	// deallocate the death-row cache outside the zone lock
-	while (idx != idx_max) {
-		deallocate_pages(szone, (void *) local_entry_cache[idx].address, local_entry_cache[idx].size, 0);
-		if (++idx == LARGE_ENTRY_CACHE_SIZE) idx = 0;
-	}
-	if (0 != local_entry_cache[idx].address && 0 != local_entry_cache[idx].size) {
-		deallocate_pages(szone, (void *) local_entry_cache[idx].address, local_entry_cache[idx].size, 0);
+	size_t index;
+	large_entry_t *large;
+	vm_range_t range_to_deallocate;
+
+#if CONFIG_LARGE_CACHE
+	if (large_cache_enabled) {
+		SZONE_LOCK(szone);
+
+		/* disable any memory pressure responder */
+		szone->flotsam_enabled = FALSE;
+
+		// stack allocated copy of the death-row cache
+		int idx = szone->large_entry_cache_oldest, idx_max = szone->large_entry_cache_newest;
+		large_entry_t local_entry_cache[LARGE_ENTRY_CACHE_SIZE_HIGH];
+
+		memcpy((void *)local_entry_cache, (void *)szone->large_entry_cache, sizeof(local_entry_cache));
+
+		szone->large_entry_cache_oldest = szone->large_entry_cache_newest = 0;
+		szone->large_entry_cache[0].address = 0x0;
+		szone->large_entry_cache[0].size = 0;
+		szone->large_entry_cache_bytes = 0;
+		szone->large_entry_cache_reserve_bytes = 0;
+
+		SZONE_UNLOCK(szone);
+
+		// deallocate the death-row cache outside the zone lock
+		while (idx != idx_max) {
+			mvm_deallocate_pages((void *)local_entry_cache[idx].address, local_entry_cache[idx].size, szone->debug_flags);
+			if (++idx == szone->large_cache_depth) {
+				idx = 0;
+			}
+		}
+		if (0 != local_entry_cache[idx].address && 0 != local_entry_cache[idx].size) {
+			mvm_deallocate_pages((void *)local_entry_cache[idx].address, local_entry_cache[idx].size, szone->debug_flags);
+		}
 	}
 #endif
 
@@ -6877,151 +701,193 @@
 		large = szone->large_entries + index;
 		if (large->address) {
 			// we deallocate_pages, including guard pages
-			deallocate_pages(szone, (void *)(large->address), large->size, szone->debug_flags);
+			mvm_deallocate_pages((void *)(large->address), large->size, szone->debug_flags);
 		}
 	}
 	large_entries_free_no_lock(szone, szone->large_entries, szone->num_large_entries, &range_to_deallocate);
-	if (range_to_deallocate.size)
-		deallocate_pages(szone, (void *)range_to_deallocate.address, (size_t)range_to_deallocate.size, 0);
-
-	/* destroy tiny regions */
-	for (index = 0; index < szone->tiny_region_generation->num_regions_allocated; ++index)
-		if ((HASHRING_OPEN_ENTRY != szone->tiny_region_generation->hashed_regions[index]) &&
-			(HASHRING_REGION_DEALLOCATED != szone->tiny_region_generation->hashed_regions[index]))
-			deallocate_pages(szone, szone->tiny_region_generation->hashed_regions[index], TINY_REGION_SIZE, 0);
-
-	/* destroy small regions */
-	for (index = 0; index < szone->small_region_generation->num_regions_allocated; ++index)
-		if ((HASHRING_OPEN_ENTRY != szone->small_region_generation->hashed_regions[index]) &&
-			(HASHRING_REGION_DEALLOCATED != szone->small_region_generation->hashed_regions[index]))
-			deallocate_pages(szone, szone->small_region_generation->hashed_regions[index], SMALL_REGION_SIZE, 0);
-
-	/* destroy region hash rings, if any */
-	if (szone->tiny_region_generation->hashed_regions != szone->initial_tiny_regions) {
-		size_t size = round_page_quanta(szone->tiny_region_generation->num_regions_allocated * sizeof(region_t));
-		deallocate_pages(szone, szone->tiny_region_generation->hashed_regions, size, 0);
-	}
-	if (szone->small_region_generation->hashed_regions != szone->initial_small_regions) {
-		size_t size = round_page_quanta(szone->small_region_generation->num_regions_allocated * sizeof(region_t));
-		deallocate_pages(szone, szone->small_region_generation->hashed_regions, size, 0);
-	}
-
-	/* Now destroy the separate szone region */
-	deallocate_pages(szone, (void *)&(szone->tiny_magazines[-1]), TINY_MAGAZINE_PAGED_SIZE, SCALABLE_MALLOC_ADD_GUARD_PAGES);
-	deallocate_pages(szone, (void *)&(szone->small_magazines[-1]), SMALL_MAGAZINE_PAGED_SIZE, SCALABLE_MALLOC_ADD_GUARD_PAGES);
-	deallocate_pages(szone, (void *)szone, SZONE_PAGED_SIZE, 0);
-}
-
-static NOINLINE size_t
+	if (range_to_deallocate.size) {
+		mvm_deallocate_pages((void *)range_to_deallocate.address, (size_t)range_to_deallocate.size, szone->debug_flags);
+	}
+
+	/* destroy allocator regions */
+	rack_destroy_regions(&szone->tiny_rack, TINY_REGION_SIZE);
+	rack_destroy_regions(&szone->small_rack, SMALL_REGION_SIZE);
+
+	/* destroy rack region hash rings and racks themselves */
+	rack_destroy(&szone->tiny_rack);
+	rack_destroy(&szone->small_rack);
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		rack_destroy_regions(&szone->medium_rack, MEDIUM_REGION_SIZE);
+		rack_destroy(&szone->medium_rack);
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	mvm_deallocate_pages((void *)szone, SZONE_PAGED_SIZE, 0);
+}
+
+size_t
 szone_good_size(szone_t *szone, size_t size)
 {
 	msize_t msize;
 
 	// Find a good size for this tiny allocation.
-	if (size <= (NUM_TINY_SLOTS - 1) * TINY_QUANTUM) {
+	if (size <= TINY_LIMIT_THRESHOLD) {
 		msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
-		if (!msize)
+		if (!msize) {
 			msize = 1;
+		}
 		return TINY_BYTES_FOR_MSIZE(msize);
 	}
 
 	// Find a good size for this small allocation.
-	if (size <= szone->large_threshold) {
+	if (size <= SMALL_LIMIT_THRESHOLD) {
 		msize = SMALL_MSIZE_FOR_BYTES(size + SMALL_QUANTUM - 1);
-		if (!msize)
+		if (!msize) {
 			msize = 1;
+		}
 		return SMALL_BYTES_FOR_MSIZE(msize);
 	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged && size <= MEDIUM_LIMIT_THRESHOLD) {
+		msize = MEDIUM_MSIZE_FOR_BYTES(size + MEDIUM_QUANTUM - 1);
+		if (!msize) {
+			msize = 1;
+		}
+		return MEDIUM_BYTES_FOR_MSIZE(msize);
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
 
 	// Check for integer overflow on the size, since unlike the two cases above,
 	// there is no upper bound on allocation size at this point.
-	if (size > round_page_quanta(size))
+	if (size > round_large_page_quanta(size)) {
 		return (size_t)(-1LL);
+	}
 
 #if DEBUG_MALLOC
 	// It is not acceptable to see a size of zero here, since that means we
 	// failed to catch a request for zero bytes in the tiny check, or the size
 	// overflowed to zero during some arithmetic.
-	if (size == 0)
-		malloc_printf("szone_good_size() invariant broken %y\n", size);
-#endif
-	return round_page_quanta(size);
+	if (size == 0) {
+		malloc_report(ASL_LEVEL_INFO, "szone_good_size() invariant broken %y\n", size);
+	}
+#endif
+	return round_large_page_quanta(size);
+}
+
+boolean_t
+szone_claimed_address(szone_t *szone, void *ptr)
+{
+	return tiny_claimed_address(&szone->tiny_rack, ptr)
+			|| small_claimed_address(&szone->small_rack, ptr)
+#if CONFIG_MEDIUM_ALLOCATOR
+			|| (szone->is_medium_engaged &&
+					medium_claimed_address(&szone->medium_rack, ptr))
+#endif // CONFIG_MEDIUM_ALLOCATOR
+			|| large_claimed_address(szone, ptr);
 }
 
 unsigned szone_check_counter = 0;
 unsigned szone_check_start = 0;
 unsigned szone_check_modulo = 1;
 
-static NOINLINE boolean_t
+static MALLOC_NOINLINE boolean_t
 szone_check_all(szone_t *szone, const char *function)
 {
 	size_t index;
 
 	/* check tiny regions - chould check region count */
-	for (index = 0; index < szone->tiny_region_generation->num_regions_allocated; ++index) {
-		region_t tiny = szone->tiny_region_generation->hashed_regions[index];
-
-		if (HASHRING_REGION_DEALLOCATED == tiny)
+	for (index = 0; index < szone->tiny_rack.region_generation->num_regions_allocated; ++index) {
+		region_t tiny = szone->tiny_rack.region_generation->hashed_regions[index];
+
+		if (HASHRING_REGION_DEALLOCATED == tiny) {
 			continue;
+		}
 
 		if (tiny) {
-			magazine_t *tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines,
-																		REGION_TRAILER_FOR_TINY_REGION(tiny), MAGAZINE_INDEX_FOR_TINY_REGION(tiny));
-
-			if (!tiny_check_region(szone, tiny)) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
-				szone->debug_flags &= ~ CHECK_REGIONS;
-				szone_error(szone, 1, "check: tiny region incorrect", NULL,
-							"*** tiny region %ld incorrect szone_check_all(%s) counter=%d\n",
-							index, function, szone_check_counter);
+			magazine_t *tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone->tiny_rack.magazines,
+					REGION_TRAILER_FOR_TINY_REGION(tiny),
+					MAGAZINE_INDEX_FOR_TINY_REGION(tiny));
+
+			if (!tiny_check_region(&szone->tiny_rack, tiny, index, szone_check_counter)) {
+				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
+				szone->debug_flags &= ~CHECK_REGIONS;
 				return 0;
 			}
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
+			SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
 		}
 	}
 	/* check tiny free lists */
 	for (index = 0; index < NUM_TINY_SLOTS; ++index) {
-		if (!tiny_free_list_check(szone, index)) {
-			szone->debug_flags &= ~ CHECK_REGIONS;
-			szone_error(szone, 1, "check: tiny free list incorrect", NULL,
-						"*** tiny free list incorrect (slot=%ld) szone_check_all(%s) counter=%d\n",
-						index, function, szone_check_counter);
+		if (!tiny_free_list_check(&szone->tiny_rack, (grain_t)index, szone_check_counter)) {
+			szone->debug_flags &= ~CHECK_REGIONS;
 			return 0;
 		}
 	}
 
 	/* check small regions - could check region count */
-	for (index = 0; index < szone->small_region_generation->num_regions_allocated; ++index) {
-		region_t small = szone->small_region_generation->hashed_regions[index];
-
-		if (HASHRING_REGION_DEALLOCATED == small)
+	for (index = 0; index < szone->small_rack.region_generation->num_regions_allocated; ++index) {
+		region_t small = szone->small_rack.region_generation->hashed_regions[index];
+
+		if (HASHRING_REGION_DEALLOCATED == small) {
 			continue;
+		}
 
 		if (small) {
-			magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->small_magazines,
-																		 REGION_TRAILER_FOR_SMALL_REGION(small), MAGAZINE_INDEX_FOR_SMALL_REGION(small));
-
-			if (!small_check_region(szone, small)) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
-				szone->debug_flags &= ~ CHECK_REGIONS;
-				szone_error(szone, 1, "check: small region incorrect", NULL,
-							"*** small region %ld incorrect szone_check_all(%s) counter=%d\n",
-							index, function, szone_check_counter);
+			magazine_t *small_mag_ptr = mag_lock_zine_for_region_trailer(szone->small_rack.magazines,
+					REGION_TRAILER_FOR_SMALL_REGION(small),
+					MAGAZINE_INDEX_FOR_SMALL_REGION(small));
+
+			if (!small_check_region(&szone->small_rack, small, index, szone_check_counter)) {
+				SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
+				szone->debug_flags &= ~CHECK_REGIONS;
 				return 0;
 			}
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
+			SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
 		}
 	}
 	/* check small free lists */
-	for (index = 0; index < szone->num_small_slots; ++index) {
-		if (!small_free_list_check(szone, index)) {
-			szone->debug_flags &= ~ CHECK_REGIONS;
-			szone_error(szone, 1, "check: small free list incorrect", NULL,
-						"*** small free list incorrect (slot=%ld) szone_check_all(%s) counter=%d\n",
-						index, function, szone_check_counter);
+	for (index = 0; index < SMALL_FREE_SLOT_COUNT(&szone->small_rack); ++index) {
+		if (!small_free_list_check(&szone->small_rack, (grain_t)index, szone_check_counter)) {
+			szone->debug_flags &= ~CHECK_REGIONS;
 			return 0;
 		}
 	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		/* check medium regions - could check region count */
+		for (index = 0; index < szone->medium_rack.region_generation->num_regions_allocated; ++index) {
+			region_t medium = szone->medium_rack.region_generation->hashed_regions[index];
+
+			if (HASHRING_REGION_DEALLOCATED == medium) {
+				continue;
+			}
+
+			if (medium) {
+				magazine_t *medium_mag_ptr = mag_lock_zine_for_region_trailer(szone->medium_rack.magazines,
+						REGION_TRAILER_FOR_MEDIUM_REGION(medium),
+						MAGAZINE_INDEX_FOR_MEDIUM_REGION(medium));
+
+				if (!medium_check_region(&szone->medium_rack, medium, index, szone_check_counter)) {
+					SZONE_MAGAZINE_PTR_UNLOCK(medium_mag_ptr);
+					szone->debug_flags &= ~CHECK_REGIONS;
+					return 0;
+				}
+				SZONE_MAGAZINE_PTR_UNLOCK(medium_mag_ptr);
+			}
+		}
+		/* check medium free lists */
+		for (index = 0; index < MEDIUM_FREE_SLOT_COUNT(&szone->medium_rack); ++index) {
+			if (!medium_free_list_check(&szone->medium_rack, (grain_t)index, szone_check_counter)) {
+				szone->debug_flags &= ~CHECK_REGIONS;
+				return 0;
+			}
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
 
 	return 1;
 }
@@ -7029,77 +895,110 @@
 static boolean_t
 szone_check(szone_t *szone)
 {
-	if ((++szone_check_counter % 10000) == 0)
-		_malloc_printf(ASL_LEVEL_NOTICE, "at szone_check counter=%d\n", szone_check_counter);
-
-	if (szone_check_counter < szone_check_start)
+	if ((++szone_check_counter % 10000) == 0) {
+		malloc_report(ASL_LEVEL_NOTICE, "at szone_check counter=%d\n", szone_check_counter);
+	}
+
+	if (szone_check_counter < szone_check_start) {
 		return 1;
-
-	if (szone_check_counter % szone_check_modulo)
+	}
+
+	if (szone_check_counter % szone_check_modulo) {
 		return 1;
+	}
 
 	return szone_check_all(szone, "");
 }
 
 static kern_return_t
-szone_ptr_in_use_enumerator(task_t task, void *context, unsigned type_mask, vm_address_t zone_address,
-							memory_reader_t reader, vm_range_recorder_t recorder)
-{
-	szone_t		*szone;
-	kern_return_t	err;
-
-	if (!reader) reader = _szone_default_reader;
+szone_ptr_in_use_enumerator(task_t task,
+		void *context,
+		unsigned type_mask,
+		vm_address_t zone_address,
+		memory_reader_t reader,
+		vm_range_recorder_t recorder)
+{
+	szone_t *szone;
+	kern_return_t err;
+
+	if (!reader) {
+		reader = _malloc_default_reader;
+	}
 
 	err = reader(task, zone_address, sizeof(szone_t), (void **)&szone);
-	if (err) return err;
+	if (err) {
+		return err;
+	}
 
 	err = tiny_in_use_enumerator(task, context, type_mask, szone, reader, recorder);
-	if (err) return err;
+	if (err) {
+		return err;
+	}
 
 	err = small_in_use_enumerator(task, context, type_mask, szone, reader, recorder);
-	if (err) return err;
-
-	err = large_in_use_enumerator(task, context, type_mask,
-								  (vm_address_t)szone->large_entries, szone->num_large_entries, reader, recorder);
+	if (err) {
+		return err;
+	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		err = medium_in_use_enumerator(task, context, type_mask, szone, reader, recorder);
+		if (err) {
+			return err;
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	err = large_in_use_enumerator(
+			task, context, type_mask, (vm_address_t)szone->large_entries, szone->num_large_entries, reader, recorder);
 	return err;
 }
 
-// Following method is deprecated:  use scalable_zone_statistics instead
-void
-scalable_zone_info(malloc_zone_t *zone, unsigned *info_to_fill, unsigned count)
-{
-	szone_t	*szone = (void *)zone;
-	unsigned	info[13];
+static boolean_t
+scalable_zone_info_task(task_t task, memory_reader_t reader,
+		malloc_zone_t *zone, unsigned *info_to_fill, unsigned count)
+{
+	szone_t *szone = (void *)zone;
+	unsigned info[13];
 
 	// We do not lock to facilitate debug
 
-	size_t	s = 0;
-	unsigned	t = 0;
-	size_t	u = 0;
+	size_t s = 0;
+	unsigned t = 0;
+	size_t u = 0;
 	mag_index_t mag_index;
 
-	for (mag_index = -1; mag_index < szone->num_tiny_magazines; mag_index++) {
-		s += szone->tiny_magazines[mag_index].mag_bytes_free_at_start;
-		s += szone->tiny_magazines[mag_index].mag_bytes_free_at_end;
-		t += szone->tiny_magazines[mag_index].mag_num_objects;
-		u += szone->tiny_magazines[mag_index].mag_num_bytes_in_objects;
-	}
-
-	info[4] = t;
-	info[5] = u;
-
-	for (t = 0, u = 0, mag_index = -1; mag_index < szone->num_small_magazines; mag_index++) {
-		s += szone->small_magazines[mag_index].mag_bytes_free_at_start;
-		s += szone->small_magazines[mag_index].mag_bytes_free_at_end;
-		t += szone->small_magazines[mag_index].mag_num_objects;
-		u += szone->small_magazines[mag_index].mag_num_bytes_in_objects;
-	}
-
-	info[6] = t;
-	info[7] = u;
-
-	info[8] = szone->num_large_objects_in_use;
-	info[9] = szone->num_bytes_in_large_objects;
+	magazine_t *mapped_magazines;
+	if (reader(task, (vm_address_t)szone->tiny_rack.magazines,
+			sizeof(magazine_t), (void **)&mapped_magazines)) {
+		return false;
+	}
+	for (mag_index = -1; mag_index < szone->tiny_rack.num_magazines; mag_index++) {
+		s += mapped_magazines[mag_index].mag_bytes_free_at_start;
+		s += mapped_magazines[mag_index].mag_bytes_free_at_end;
+		t += mapped_magazines[mag_index].mag_num_objects;
+		u += mapped_magazines[mag_index].mag_num_bytes_in_objects;
+	}
+
+	info[4] = (unsigned)t;
+	info[5] = (unsigned)u;
+
+	if (reader(task, (vm_address_t)szone->small_rack.magazines,
+			sizeof(magazine_t), (void **)&mapped_magazines)) {
+		return false;
+	}
+	for (t = 0, u = 0, mag_index = -1; mag_index < szone->small_rack.num_magazines; mag_index++) {
+		s += mapped_magazines[mag_index].mag_bytes_free_at_start;
+		s += mapped_magazines[mag_index].mag_bytes_free_at_end;
+		t += mapped_magazines[mag_index].mag_num_objects;
+		u += mapped_magazines[mag_index].mag_num_bytes_in_objects;
+	}
+
+	info[6] = (unsigned)t;
+	info[7] = (unsigned)u;
+
+	info[8] = (unsigned)szone->num_large_objects_in_use;
+	info[9] = (unsigned)szone->num_bytes_in_large_objects;
 
 	info[10] = 0; // DEPRECATED szone->num_huge_entries;
 	info[11] = 0; // DEPRECATED szone->num_bytes_in_huge_objects;
@@ -7109,87 +1008,293 @@
 	info[0] = info[4] + info[6] + info[8] + info[10];
 	info[1] = info[5] + info[7] + info[9] + info[11];
 
-	info[3] = (szone->num_tiny_regions - szone->num_tiny_regions_dealloc) * TINY_REGION_SIZE +
-	(szone->num_small_regions - szone->num_small_regions_dealloc) * SMALL_REGION_SIZE + info[9] + info[11];
-
-	info[2] = info[3] - s;
-	memcpy(info_to_fill, info, sizeof(unsigned)*count);
+	info[3] = (unsigned)(szone->tiny_rack.num_regions - szone->tiny_rack.num_regions_dealloc) * TINY_REGION_SIZE +
+			  (unsigned)(szone->small_rack.num_regions - szone->small_rack.num_regions_dealloc) * SMALL_REGION_SIZE + info[9] + info[11];
+
+	info[2] = info[3] - (unsigned)s;
+	memcpy(info_to_fill, info, sizeof(unsigned) * count);
+
+	return true;
+}
+
+// Following method is deprecated:  use scalable_zone_statistics instead
+// Required for backward compatibility.
+void
+scalable_zone_info(malloc_zone_t *zone, unsigned *info_to_fill, unsigned count) {
+	scalable_zone_info_task(mach_task_self(), _malloc_default_reader, zone,
+			info_to_fill, count);
 }
 
 // FIXME: consistent picture requires locking!
-static NOINLINE void
-szone_print(szone_t *szone, boolean_t verbose)
-{
-	unsigned	info[13];
-	size_t	index;
-	region_t	region;
-
-	scalable_zone_info((void *)szone, info, 13);
-	_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-				   "Scalable zone %p: inUse=%u(%y) touched=%y allocated=%y flags=%d\n",
-				   szone, info[0], info[1], info[2], info[3], info[12]);
-	_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-				   "\ttiny=%u(%y) small=%u(%y) large=%u(%y) huge=%u(%y)\n",
-				   info[4], info[5], info[6], info[7], info[8], info[9], info[10], info[11]);
+static MALLOC_NOINLINE void
+szone_print(task_t task, unsigned level, vm_address_t zone_address,
+		memory_reader_t reader, print_task_printer_t printer)
+{
+	unsigned info[13];
+	size_t index;
+	region_t region;
+	region_t mapped_region;
+
+	szone_t *szone = (szone_t *)zone_address;
+	szone_t *mapped_szone;
+	if (reader(task, zone_address, sizeof(szone_t), (void **)&mapped_szone)) {
+		printer("Failed to read szone structure\n");
+		return;
+	}
+
+	if (!scalable_zone_info_task(task, reader, (void *)mapped_szone, info, 13)) {
+		printer("Failed to get scalable zone info\n");
+		return;
+	}
+	printer("Scalable zone %p: inUse=%u(%u) touched=%u allocated=%u flags=0x%x\n",
+			zone_address, info[0], info[1], info[2], info[3], info[12]);
+	printer("\ttiny=%u(%u) small=%u(%u) large=%u(%u)\n", info[4],
+			info[5], info[6], info[7], info[8], info[9]);
 	// tiny
-	_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-				   "%lu tiny regions:\n", szone->num_tiny_regions);
-	if (szone->num_tiny_regions_dealloc)
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-					   "[%lu tiny regions have been vm_deallocate'd]\n", szone->num_tiny_regions_dealloc);
-	for (index = 0; index < szone->tiny_region_generation->num_regions_allocated; ++index) {
-		region = szone->tiny_region_generation->hashed_regions[index];
+	printer("%lu tiny regions:\n", mapped_szone->tiny_rack.num_regions);
+	if (mapped_szone->tiny_rack.num_regions_dealloc) {
+		printer("[%lu tiny regions have been vm_deallocate'd]\n",
+				mapped_szone->tiny_rack.num_regions_dealloc);
+	}
+
+	region_hash_generation_t *mapped_region_generation;
+	region_t *mapped_hashed_regions;
+	magazine_t *mapped_magazines;
+	if (reader(task, (vm_address_t)mapped_szone->tiny_rack.region_generation,
+			sizeof(region_hash_generation_t), (void **)&mapped_region_generation)) {
+		printer("Failed to map tiny rack region_generation\n");
+		return;
+	}
+	if (reader(task, (vm_address_t)mapped_region_generation->hashed_regions,
+			sizeof(region_t), (void **)&mapped_hashed_regions)) {
+		printer("Failed to map tiny rack hashed_regions\n");
+		return;
+	}
+	if (reader(task, (vm_address_t)mapped_szone->tiny_rack.magazines,
+			mapped_szone->tiny_rack.num_magazines * sizeof(magazine_t),
+			(void **)&mapped_magazines)) {
+		printer("Failed to map tiny rack magazines\n");
+		return;
+	}
+
+	int recirc_regions = 0;
+	for (index = 0; index < mapped_region_generation->num_regions_allocated; ++index) {
+		region = mapped_hashed_regions[index];
 		if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
-			mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(region);
-			print_tiny_region(verbose, region,
-							  (region == szone->tiny_magazines[mag_index].mag_last_region) ?
-							  szone->tiny_magazines[mag_index].mag_bytes_free_at_start : 0,
-							  (region == szone->tiny_magazines[mag_index].mag_last_region) ?
-							  szone->tiny_magazines[mag_index].mag_bytes_free_at_end : 0);
-		}
-	}
-	if (verbose)
-		print_tiny_free_list(szone);
+			if (reader(task, (vm_address_t)region, sizeof(struct tiny_region),
+					(void **)&mapped_region)) {
+				printer("Failed to map region %p\n", region);
+				return;
+			}
+			mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(mapped_region);
+			if (mag_index == DEPOT_MAGAZINE_INDEX) {
+				recirc_regions++;
+			}
+			print_tiny_region(task, reader, printer, level, region,
+					(region == mapped_magazines[mag_index].mag_last_region)
+						? mapped_magazines[mag_index].mag_bytes_free_at_start
+						: 0,
+					(region == mapped_magazines[mag_index].mag_last_region)
+						? mapped_magazines[mag_index].mag_bytes_free_at_end
+						: 0);
+		}
+	}
+
+#if CONFIG_RECIRC_DEPOT
+	magazine_t *mapped_recirc_depot = &mapped_magazines[DEPOT_MAGAZINE_INDEX];
+	if (mapped_recirc_depot->mag_num_bytes_in_objects) {
+		printer("Tiny recirc depot: total bytes: %llu, in-use bytes: %llu, "
+				"allocations: %llu, regions: %d (min # retained regions: %d)\n",
+				mapped_recirc_depot->num_bytes_in_magazine,
+				mapped_recirc_depot->mag_num_bytes_in_objects,
+				mapped_recirc_depot->mag_num_objects, recirc_regions,
+				recirc_retained_regions);
+	} else {
+		printer("Tiny recirc depot is empty\n");
+	}
+#else // CONFIG_RECIRC_DEPOT
+	printer("Tiny recirc depot not configured\n");
+#endif // CONFIG_RECIRC_DEPOT
+
+	if (level > 0) {
+		print_tiny_free_list(task, reader, printer, &szone->tiny_rack);
+	}
+
 	// small
-	_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-				   "%lu small regions:\n", szone->num_small_regions);
-	if (szone->num_small_regions_dealloc)
-		_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-					   "[%lu small regions have been vm_deallocate'd]\n", szone->num_small_regions_dealloc);
-	for (index = 0; index < szone->small_region_generation->num_regions_allocated; ++index) {
-		region = szone->small_region_generation->hashed_regions[index];
+	printer("%lu small regions:\n", mapped_szone->small_rack.num_regions);
+	if (mapped_szone->small_rack.num_regions_dealloc) {
+		printer("[%lu small regions have been vm_deallocate'd]\n",
+				mapped_szone->small_rack.num_regions_dealloc);
+	}
+	if (reader(task, (vm_address_t)mapped_szone->small_rack.region_generation,
+			sizeof(region_hash_generation_t), (void **)&mapped_region_generation)) {
+		printer("Failed to map small rack region_generation\n");
+		return;
+	}
+	if (reader(task, (vm_address_t)mapped_region_generation->hashed_regions,
+			sizeof(region_t), (void **)&mapped_hashed_regions)) {
+		printer("Failed to map small rack hashed_regions\n");
+		return;
+	}
+	if (reader(task, (vm_address_t)mapped_szone->small_rack.magazines,
+			mapped_szone->small_rack.num_magazines * sizeof(magazine_t),
+			(void **)&mapped_magazines)) {
+		printer("Failed to map small rack magazines\n");
+		return;
+	}
+
+	recirc_regions = 0;
+	for (index = 0; index < mapped_region_generation->num_regions_allocated; ++index) {
+		region = mapped_hashed_regions[index];
 		if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
-			mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(region);
-			print_small_region(szone, verbose, region,
-							   (region == szone->small_magazines[mag_index].mag_last_region) ?
-							   szone->small_magazines[mag_index].mag_bytes_free_at_start : 0,
-							   (region == szone->small_magazines[mag_index].mag_last_region) ?
-							   szone->small_magazines[mag_index].mag_bytes_free_at_end : 0);
-		}
-	}
-	if (verbose)
-		print_small_free_list(szone);
+			if (reader(task, (vm_address_t)region, sizeof(struct small_region),
+					(void **)&mapped_region)) {
+				printer("Failed to map region %p\n", region);
+				return;
+			}
+			mag_index_t mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(mapped_region);
+			if (mag_index == DEPOT_MAGAZINE_INDEX) {
+				recirc_regions++;
+			}
+			print_small_region(task, reader, printer, mapped_szone, level, region,
+					(region == mapped_magazines[mag_index].mag_last_region)
+						? mapped_magazines[mag_index].mag_bytes_free_at_start
+						: 0,
+					(region == mapped_magazines[mag_index].mag_last_region)
+						? mapped_magazines[mag_index].mag_bytes_free_at_end
+						: 0);
+		}
+	}
+
+#if CONFIG_RECIRC_DEPOT
+	mapped_recirc_depot = &mapped_magazines[DEPOT_MAGAZINE_INDEX];
+	if (mapped_recirc_depot->mag_num_bytes_in_objects) {
+		printer("Small recirc depot: total bytes: %llu, in-use bytes: %llu, "
+				"allocations: %llu, regions: %d (min # retained regions: %d)\n",
+				mapped_recirc_depot->num_bytes_in_magazine,
+				mapped_recirc_depot->mag_num_bytes_in_objects,
+				mapped_recirc_depot->mag_num_objects, recirc_regions,
+				recirc_retained_regions);
+	} else {
+		printer("Small recirc depot is empty\n");
+	}
+#else // CONFIG_RECIRC_DEPOT
+	printer("Small recirc depot not configured\n");
+#endif // CONFIG_RECIRC_DEPOT
+
+	if (level > 0) {
+		print_small_free_list(task, reader, printer, &szone->small_rack);
+	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		// medium
+		printer("%lu medium regions:\n", mapped_szone->medium_rack.num_regions);
+		if (mapped_szone->medium_rack.num_regions_dealloc) {
+			printer("[%lu medium regions have been vm_deallocate'd]\n",
+					mapped_szone->medium_rack.num_regions_dealloc);
+		}
+		if (reader(task, (vm_address_t)mapped_szone->medium_rack.region_generation,
+				sizeof(region_hash_generation_t), (void **)&mapped_region_generation)) {
+			printer("Failed to map medium rack region_generation\n");
+			return;
+		}
+		if (reader(task, (vm_address_t)mapped_region_generation->hashed_regions,
+				sizeof(region_t), (void **)&mapped_hashed_regions)) {
+			printer("Failed to map medium rack hashed_regions\n");
+			return;
+		}
+		if (reader(task, (vm_address_t)mapped_szone->medium_rack.magazines,
+				mapped_szone->medium_rack.num_magazines * sizeof(magazine_t),
+				(void **)&mapped_magazines)) {
+			printer("Failed to map medium rack magazines\n");
+			return;
+		}
+
+		recirc_regions = 0;
+		for (index = 0; index < mapped_region_generation->num_regions_allocated; ++index) {
+			region = mapped_hashed_regions[index];
+			if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
+				if (reader(task, (vm_address_t)region, sizeof(struct medium_region),
+						(void **)&mapped_region)) {
+					printer("Failed to map region %p\n", region);
+					return;
+				}
+				mag_index_t mag_index = MAGAZINE_INDEX_FOR_MEDIUM_REGION(mapped_region);
+				if (mag_index == DEPOT_MAGAZINE_INDEX) {
+					recirc_regions++;
+				}
+				print_medium_region(task, reader, printer, mapped_szone, level,
+						region,
+						(region == mapped_magazines[mag_index].mag_last_region)
+							? mapped_magazines[mag_index].mag_bytes_free_at_start
+							: 0,
+						(region == mapped_magazines[mag_index].mag_last_region)
+							? mapped_magazines[mag_index].mag_bytes_free_at_end
+							: 0);
+			}
+		}
+
+#if CONFIG_RECIRC_DEPOT
+		mapped_recirc_depot = &mapped_magazines[DEPOT_MAGAZINE_INDEX];
+		if (mapped_recirc_depot->mag_num_bytes_in_objects) {
+			printer("Medium recirc depot: total bytes: %llu, in-use bytes: %llu, "
+					"allocations: %llu, regions: %d (min # retained regions: %d)\n",
+					mapped_recirc_depot->num_bytes_in_magazine,
+					mapped_recirc_depot->mag_num_bytes_in_objects,
+					mapped_recirc_depot->mag_num_objects, recirc_regions,
+					recirc_retained_regions);
+		} else {
+			printer("Medium recirc depot is empty\n");
+		}
+#else // CONFIG_RECIRC_DEPOT
+		printer("Medium recirc depot not configured\n");
+#endif // CONFIG_RECIRC_DEPOT
+
+		if (level > 0) {
+			print_medium_free_list(task, reader, printer, &szone->medium_rack);
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	// Large
+	large_debug_print(task, level, zone_address, reader, printer);
+}
+
+static void
+szone_print_self(szone_t *szone, boolean_t verbose)
+{
+	szone_print(mach_task_self(), verbose ? MALLOC_VERBOSE_PRINT_LEVEL : 0,
+			(vm_address_t)szone, _malloc_default_reader, malloc_report_simple);
+}
+
+static void
+szone_print_task(task_t task, unsigned level, vm_address_t zone_address,
+		memory_reader_t reader, print_task_printer_t printer)
+{
+	szone_print(task, level, zone_address, reader, printer);
 }
 
 static void
 szone_log(malloc_zone_t *zone, void *log_address)
 {
-	szone_t	*szone = (szone_t *)zone;
+	szone_t *szone = (szone_t *)zone;
 
 	szone->log_address = log_address;
 }
 
 // <rdar://problem/18001324>
 // When forcing the lock on the entire zone, make sure we are out of the critical section in each magazine
-static INLINE void
+static MALLOC_INLINE void
 szone_force_lock_magazine(szone_t *szone, magazine_t *mag)
 {
 	while (1) {
-		SZONE_MAGAZINE_PTR_LOCK(szone, mag);
-		if (!mag->alloc_underway)
+		SZONE_MAGAZINE_PTR_LOCK(mag);
+		if (!mag->alloc_underway) {
 			return;
-
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, mag);
+		}
+
+		SZONE_MAGAZINE_PTR_UNLOCK(mag);
 		yield();
 	}
 }
@@ -7199,15 +1304,24 @@
 {
 	mag_index_t i;
 
-	for (i = 0; i < szone->num_tiny_magazines; ++i) {
-		szone_force_lock_magazine(szone, &szone->tiny_magazines[i]);
-	}
-	szone_force_lock_magazine(szone, &szone->tiny_magazines[DEPOT_MAGAZINE_INDEX]);
-
-	for (i = 0; i < szone->num_small_magazines; ++i) {
-		szone_force_lock_magazine(szone, &szone->small_magazines[i]);
-	}
-	szone_force_lock_magazine(szone, &szone->small_magazines[DEPOT_MAGAZINE_INDEX]);
+	for (i = 0; i < szone->tiny_rack.num_magazines; ++i) {
+		szone_force_lock_magazine(szone, &szone->tiny_rack.magazines[i]);
+	}
+	szone_force_lock_magazine(szone, &szone->tiny_rack.magazines[DEPOT_MAGAZINE_INDEX]);
+
+	for (i = 0; i < szone->small_rack.num_magazines; ++i) {
+		szone_force_lock_magazine(szone, &szone->small_rack.magazines[i]);
+	}
+	szone_force_lock_magazine(szone, &szone->small_rack.magazines[DEPOT_MAGAZINE_INDEX]);
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		for (i = 0; i < szone->medium_rack.num_magazines; ++i) {
+			szone_force_lock_magazine(szone, &szone->medium_rack.magazines[i]);
+		}
+		szone_force_lock_magazine(szone, &szone->medium_rack.magazines[DEPOT_MAGAZINE_INDEX]);
+	}
+#endif
 
 	SZONE_LOCK(szone);
 }
@@ -7219,12 +1333,44 @@
 
 	SZONE_UNLOCK(szone);
 
-	for (i = -1; i < szone->num_small_magazines; ++i) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, (&(szone->small_magazines[i])));
-	}
-
-	for (i = -1; i < szone->num_tiny_magazines; ++i) {
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, (&(szone->tiny_magazines[i])));
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		for (i = -1; i < szone->medium_rack.num_magazines; ++i) {
+			SZONE_MAGAZINE_PTR_UNLOCK((&(szone->medium_rack.magazines[i])));
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	for (i = -1; i < szone->small_rack.num_magazines; ++i) {
+		SZONE_MAGAZINE_PTR_UNLOCK((&(szone->small_rack.magazines[i])));
+	}
+
+	for (i = -1; i < szone->tiny_rack.num_magazines; ++i) {
+		SZONE_MAGAZINE_PTR_UNLOCK((&(szone->tiny_rack.magazines[i])));
+	}
+}
+
+static void
+szone_reinit_lock(szone_t *szone)
+{
+	mag_index_t i;
+
+	SZONE_REINIT_LOCK(szone);
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		for (i = -1; i < szone->medium_rack.num_magazines; ++i) {
+			SZONE_MAGAZINE_PTR_REINIT_LOCK((&(szone->medium_rack.magazines[i])));
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	for (i = -1; i < szone->small_rack.num_magazines; ++i) {
+		SZONE_MAGAZINE_PTR_REINIT_LOCK((&(szone->small_rack.magazines[i])));
+	}
+
+	for (i = -1; i < szone->tiny_rack.num_magazines; ++i) {
+		SZONE_MAGAZINE_PTR_REINIT_LOCK((&(szone->tiny_rack.magazines[i])));
 	}
 }
 
@@ -7235,189 +1381,67 @@
 	int tookLock;
 
 	tookLock = SZONE_TRY_LOCK(szone);
-	if (tookLock == 0)
+	if (tookLock == 0) {
 		return 1;
+	}
 	SZONE_UNLOCK(szone);
 
-	for (i = -1; i < szone->num_small_magazines; ++i) {
-		tookLock = SZONE_MAGAZINE_PTR_TRY_LOCK(szone, (&(szone->small_magazines[i])));
-		if (tookLock == 0)
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		for (i = -1; i < szone->small_rack.num_magazines; ++i) {
+				tookLock = SZONE_MAGAZINE_PTR_TRY_LOCK((&(szone->small_rack.magazines[i])));
+				if (tookLock == 0) {
+					return 1;
+				}
+				SZONE_MAGAZINE_PTR_UNLOCK((&(szone->small_rack.magazines[i])));
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	for (i = -1; i < szone->small_rack.num_magazines; ++i) {
+		tookLock = SZONE_MAGAZINE_PTR_TRY_LOCK((&(szone->small_rack.magazines[i])));
+		if (tookLock == 0) {
 			return 1;
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, (&(szone->small_magazines[i])));
-	}
-
-	for (i = -1; i < szone->num_tiny_magazines; ++i) {
-		tookLock = SZONE_MAGAZINE_PTR_TRY_LOCK(szone, (&(szone->tiny_magazines[i])));
-		if (tookLock == 0)
+		}
+		SZONE_MAGAZINE_PTR_UNLOCK((&(szone->small_rack.magazines[i])));
+	}
+
+	for (i = -1; i < szone->tiny_rack.num_magazines; ++i) {
+		tookLock = SZONE_MAGAZINE_PTR_TRY_LOCK((&(szone->tiny_rack.magazines[i])));
+		if (tookLock == 0) {
 			return 1;
-		SZONE_MAGAZINE_PTR_UNLOCK(szone, (&(szone->tiny_magazines[i])));
+		}
+		SZONE_MAGAZINE_PTR_UNLOCK((&(szone->tiny_rack.magazines[i])));
 	}
 	return 0;
 }
 
-static size_t
+size_t
 szone_pressure_relief(szone_t *szone, size_t goal)
 {
 	size_t total = 0;
 
-#if MADVISE_PRESSURE_RELIEF
-	mag_index_t mag_index;
-
-	magazine_t *tiny_depot_ptr = (&szone->tiny_magazines[DEPOT_MAGAZINE_INDEX]);
-	magazine_t *small_depot_ptr = (&szone->small_magazines[DEPOT_MAGAZINE_INDEX]);
-
-	for (mag_index = 0; mag_index < szone->num_tiny_magazines; mag_index++) {
-		size_t index;
-		for (index = 0; index < szone->tiny_region_generation->num_regions_allocated; ++index) {
-			SZONE_LOCK(szone);
-
-			region_t tiny = szone->tiny_region_generation->hashed_regions[index];
-			if (!tiny || tiny == HASHRING_REGION_DEALLOCATED) {
-				SZONE_UNLOCK(szone);
-				continue;
-			}
-
-			magazine_t *mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->tiny_magazines, REGION_TRAILER_FOR_TINY_REGION(tiny), MAGAZINE_INDEX_FOR_TINY_REGION(tiny));
-			SZONE_UNLOCK(szone);
-
-			/* Ordering is important here, the magazine of a region may potentially change
-			 * during mag_lock_zine_for_region_trailer, so src_mag_index must be taken
-			 * after we've obtained the lock.
-			 */
-			mag_index_t src_mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(tiny);
-
-			/* We can (and must) ignore magazines that are already in the recirc depot. */
-			if (src_mag_index == DEPOT_MAGAZINE_INDEX) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, mag_ptr);
-				continue;
-			}
-
-			if (tiny == mag_ptr->mag_last_region && (mag_ptr->mag_bytes_free_at_end || mag_ptr->mag_bytes_free_at_start)) {
-				tiny_finalize_region(szone, mag_ptr);
-			}
-
-			/* Because this region is currently in use, we can't safely madvise it while
-			 * it's attached to the magazine. For this operation we have to remove it from
-			 * the current mag, attach it to the depot and then madvise.
-			 */
-
-			recirc_list_extract(szone, mag_ptr, REGION_TRAILER_FOR_TINY_REGION(tiny));
-			int objects_in_use = tiny_free_detach_region(szone, mag_ptr, tiny);
-
-			SZONE_MAGAZINE_PTR_LOCK(szone, tiny_depot_ptr);
-			MAGAZINE_INDEX_FOR_TINY_REGION(tiny) = DEPOT_MAGAZINE_INDEX;
-			REGION_TRAILER_FOR_TINY_REGION(tiny)->pinned_to_depot = 0;
-
-			size_t bytes_inplay = tiny_free_reattach_region(szone, tiny_depot_ptr, tiny);
-
-			/* Fix up the metadata of the target magazine while the region is in the depot. */
-			mag_ptr->mag_num_bytes_in_objects -= bytes_inplay;
-			mag_ptr->num_bytes_in_magazine -= TINY_REGION_PAYLOAD_BYTES;
-			mag_ptr->mag_num_objects -= objects_in_use;
-
-			/* Now we can drop the magazine lock of the source mag. */
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, mag_ptr);
-
-			tiny_depot_ptr->mag_num_bytes_in_objects += bytes_inplay;
-			tiny_depot_ptr->num_bytes_in_magazine += TINY_REGION_PAYLOAD_BYTES;
-			tiny_depot_ptr->mag_num_objects -= objects_in_use;
-
-			recirc_list_splice_last(szone, tiny_depot_ptr, REGION_TRAILER_FOR_TINY_REGION(tiny));
-
-			/* Actually do the scan, done holding the depot lock, the call will drop the lock
-			 * around the actual madvise syscalls.
-			 */
-			tiny_free_scan_madvise_free(szone, tiny_depot_ptr, tiny);
-
-			/* Now the region is in the recirc depot, the next allocations to require more
-			 * blocks will come along and take one of these regions back out of the depot.
-			 * As OS X madvise's reuse on an per-region basis, we leave as many of these
-			 * regions in the depot as possible after memory pressure.
-			 */
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_depot_ptr);
-		}
-	}
-
-	for (mag_index = 0; mag_index < szone->num_small_magazines; mag_index++) {
-		size_t index;
-		for (index = 0; index < szone->small_region_generation->num_regions_allocated; ++index) {
-			SZONE_LOCK(szone);
-
-			region_t small = szone->small_region_generation->hashed_regions[index];
-			if (!small || small == HASHRING_REGION_DEALLOCATED) {
-				SZONE_UNLOCK(szone);
-				continue;
-			}
-
-			magazine_t *mag_ptr = mag_lock_zine_for_region_trailer(szone, szone->small_magazines, REGION_TRAILER_FOR_SMALL_REGION(small), MAGAZINE_INDEX_FOR_SMALL_REGION(small));
-			SZONE_UNLOCK(szone);
-
-			/* Ordering is important here, the magazine of a region may potentially change
-			 * during mag_lock_zine_for_region_trailer, so src_mag_index must be taken
-			 * after we've obtained the lock.
-			 */
-			mag_index_t src_mag_index = MAGAZINE_INDEX_FOR_SMALL_REGION(small);
-
-			/* We can (and must) ignore magazines that are already in the recirc depot. */
-			if (src_mag_index == DEPOT_MAGAZINE_INDEX) {
-				SZONE_MAGAZINE_PTR_UNLOCK(szone, mag_ptr);
-				continue;
-			}
-
-			if (small == mag_ptr->mag_last_region && (mag_ptr->mag_bytes_free_at_end || mag_ptr->mag_bytes_free_at_start)) {
-				small_finalize_region(szone, mag_ptr);
-			}
-
-			/* Because this region is currently in use, we can't safely madvise it while
-			 * it's attached to the magazine. For this operation we have to remove it from
-			 * the current mag, attach it to the depot and then madvise.
-			 */
-
-			recirc_list_extract(szone, mag_ptr, REGION_TRAILER_FOR_SMALL_REGION(small));
-			int objects_in_use = small_free_detach_region(szone, mag_ptr, small);
-
-			SZONE_MAGAZINE_PTR_LOCK(szone, small_depot_ptr);
-			MAGAZINE_INDEX_FOR_SMALL_REGION(small) = DEPOT_MAGAZINE_INDEX;
-			REGION_TRAILER_FOR_SMALL_REGION(small)->pinned_to_depot = 0;
-
-			size_t bytes_inplay = small_free_reattach_region(szone, small_depot_ptr, small);
-
-			/* Fix up the metadata of the target magazine while the region is in the depot. */
-			mag_ptr->mag_num_bytes_in_objects -= bytes_inplay;
-			mag_ptr->num_bytes_in_magazine -= SMALL_REGION_PAYLOAD_BYTES;
-			mag_ptr->mag_num_objects -= objects_in_use;
-
-			/* Now we can drop the magazine lock of the source mag. */
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, mag_ptr);
-
-			small_depot_ptr->mag_num_bytes_in_objects += bytes_inplay;
-			small_depot_ptr->num_bytes_in_magazine += SMALL_REGION_PAYLOAD_BYTES;
-			small_depot_ptr->mag_num_objects -= objects_in_use;
-
-			recirc_list_splice_last(szone, small_depot_ptr, REGION_TRAILER_FOR_SMALL_REGION(small));
-
-			/* Actually do the scan, done holding the depot lock, the call will drop the lock
-			 * around the actual madvise syscalls.
-			 */
-			small_free_scan_madvise_free(szone, small_depot_ptr, small);
-
-			/* Now the region is in the recirc depot, the next allocations to require more
-			 * blocks will come along and take one of these regions back out of the depot.
-			 * As OS X madvise's reuse on an per-region basis, we leave as many of these
-			 * regions in the depot as possible after memory pressure.
-			 */
-			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_depot_ptr);
-		}
-	}
-#endif
-
-#if LARGE_CACHE
-	if (szone->flotsam_enabled) {
+	MAGMALLOC_PRESSURERELIEFBEGIN((void *)szone, szone->basic_zone.zone_name, (int)goal); // DTrace USDT Probe
+	MALLOC_TRACE(TRACE_malloc_memory_pressure | DBG_FUNC_START, (uint64_t)szone, goal, 0, 0);
+
+#if CONFIG_MADVISE_PRESSURE_RELIEF
+	tiny_madvise_pressure_relief(&szone->tiny_rack);
+	small_madvise_pressure_relief(&szone->small_rack);
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		medium_madvise_pressure_relief(&szone->medium_rack);
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+#endif // CONFIG_MADVISE_PRESSURE_RELIEF
+
+#if CONFIG_LARGE_CACHE
+	if (large_cache_enabled && szone->flotsam_enabled) {
 		SZONE_LOCK(szone);
 
 		// stack allocated copy of the death-row cache
 		int idx = szone->large_entry_cache_oldest, idx_max = szone->large_entry_cache_newest;
-		large_entry_t local_entry_cache[LARGE_ENTRY_CACHE_SIZE];
+		large_entry_t local_entry_cache[LARGE_ENTRY_CACHE_SIZE_HIGH];
 
 		memcpy((void *)local_entry_cache, (void *)szone->large_entry_cache, sizeof(local_entry_cache));
 
@@ -7434,18 +1458,22 @@
 		// deallocate the death-row cache outside the zone lock
 		size_t total = 0;
 		while (idx != idx_max) {
-			deallocate_pages(szone, (void *) local_entry_cache[idx].address, local_entry_cache[idx].size, 0);
+			mvm_deallocate_pages((void *)local_entry_cache[idx].address, local_entry_cache[idx].size, szone->debug_flags);
 			total += local_entry_cache[idx].size;
-			if (++idx == LARGE_ENTRY_CACHE_SIZE) idx = 0;
+			if (++idx == szone->large_cache_depth) {
+				idx = 0;
+			}
 		}
 		if (0 != local_entry_cache[idx].address && 0 != local_entry_cache[idx].size) {
-			deallocate_pages(szone, (void *) local_entry_cache[idx].address, local_entry_cache[idx].size, 0);
+			mvm_deallocate_pages((void *)local_entry_cache[idx].address, local_entry_cache[idx].size, szone->debug_flags);
 			total += local_entry_cache[idx].size;
 		}
 	}
 #endif
 
-	MAGMALLOC_PRESSURERELIEF((void *)szone, goal, total); // DTrace USDT Probe
+	MAGMALLOC_PRESSURERELIEFEND((void *)szone, szone->basic_zone.zone_name, (int)goal, (int)total); // DTrace USDT Probe
+	MALLOC_TRACE(TRACE_malloc_memory_pressure | DBG_FUNC_END, (uint64_t)szone, goal, total, 0);
+
 	return total;
 }
 
@@ -7455,156 +1483,186 @@
 	szone_t *szone = (szone_t *)zone;
 
 	switch (subzone) {
-		case 0:
-		{
-			size_t	s = 0;
-			unsigned	t = 0;
-			size_t	u = 0;
-			mag_index_t mag_index;
-
-			for (mag_index = -1; mag_index < szone->num_tiny_magazines; mag_index++) {
-				s += szone->tiny_magazines[mag_index].mag_bytes_free_at_start;
-				s += szone->tiny_magazines[mag_index].mag_bytes_free_at_end;
-				t += szone->tiny_magazines[mag_index].mag_num_objects;
-				u += szone->tiny_magazines[mag_index].mag_num_bytes_in_objects;
+	case 0: {
+		size_t s = 0;
+		unsigned t = 0;
+		size_t u = 0;
+		mag_index_t mag_index;
+
+		for (mag_index = -1; mag_index < szone->tiny_rack.num_magazines; mag_index++) {
+			s += szone->tiny_rack.magazines[mag_index].mag_bytes_free_at_start;
+			s += szone->tiny_rack.magazines[mag_index].mag_bytes_free_at_end;
+			t += szone->tiny_rack.magazines[mag_index].mag_num_objects;
+			u += szone->tiny_rack.magazines[mag_index].mag_num_bytes_in_objects;
+		}
+
+		stats->blocks_in_use = t;
+		stats->size_in_use = u;
+		stats->size_allocated = (szone->tiny_rack.num_regions - szone->tiny_rack.num_regions_dealloc) * TINY_REGION_SIZE;
+		stats->max_size_in_use = stats->size_allocated - s;
+		return 1;
+	}
+	case 1: {
+		size_t s = 0;
+		unsigned t = 0;
+		size_t u = 0;
+		mag_index_t mag_index;
+
+		for (mag_index = -1; mag_index < szone->small_rack.num_magazines; mag_index++) {
+			s += szone->small_rack.magazines[mag_index].mag_bytes_free_at_start;
+			s += szone->small_rack.magazines[mag_index].mag_bytes_free_at_end;
+			t += szone->small_rack.magazines[mag_index].mag_num_objects;
+			u += szone->small_rack.magazines[mag_index].mag_num_bytes_in_objects;
+		}
+
+		stats->blocks_in_use = t;
+		stats->size_in_use = u;
+		stats->size_allocated = (szone->small_rack.num_regions - szone->small_rack.num_regions_dealloc) * SMALL_REGION_SIZE;
+		stats->max_size_in_use = stats->size_allocated - s;
+		return 1;
+	}
+	case 2:
+		stats->blocks_in_use = szone->num_large_objects_in_use;
+		stats->size_in_use = szone->num_bytes_in_large_objects;
+		stats->max_size_in_use = stats->size_allocated = stats->size_in_use;
+		return 1;
+	case 3:
+		stats->blocks_in_use = 0; // DEPRECATED szone->num_huge_entries;
+		stats->size_in_use = 0;   // DEPRECATED szone->num_bytes_in_huge_objects;
+		stats->max_size_in_use = stats->size_allocated = 0;
+		return 1;
+	case 4: {
+		size_t s = 0;
+		unsigned t = 0;
+		size_t u = 0;
+		size_t sa = 0;
+
+#if CONFIG_MEDIUM_ALLOCATOR
+		mag_index_t mag_index;
+		if (szone->is_medium_engaged) {
+			for (mag_index = -1; mag_index < szone->medium_rack.num_magazines; mag_index++) {
+				s += szone->medium_rack.magazines[mag_index].mag_bytes_free_at_start;
+				s += szone->medium_rack.magazines[mag_index].mag_bytes_free_at_end;
+				t += szone->medium_rack.magazines[mag_index].mag_num_objects;
+				u += szone->medium_rack.magazines[mag_index].mag_num_bytes_in_objects;
 			}
-
-			stats->blocks_in_use = t;
-			stats->size_in_use = u;
-			stats->size_allocated = (szone->num_tiny_regions - szone->num_tiny_regions_dealloc) * TINY_REGION_SIZE;
-			stats->max_size_in_use = stats->size_allocated - s;
-			return 1;
-		}
-		case 1:
-		{
-			size_t	s = 0;
-			unsigned	t = 0;
-			size_t	u = 0;
-			mag_index_t mag_index;
-
-			for (mag_index = -1; mag_index < szone->num_small_magazines; mag_index++) {
-				s += szone->small_magazines[mag_index].mag_bytes_free_at_start;
-				s += szone->small_magazines[mag_index].mag_bytes_free_at_end;
-				t += szone->small_magazines[mag_index].mag_num_objects;
-				u += szone->small_magazines[mag_index].mag_num_bytes_in_objects;
-			}
-
-			stats->blocks_in_use = t;
-			stats->size_in_use = u;
-			stats->size_allocated = (szone->num_small_regions - szone->num_small_regions_dealloc) * SMALL_REGION_SIZE;
-			stats->max_size_in_use = stats->size_allocated - s;
-			return 1;
-		}
-		case 2:
-			stats->blocks_in_use = szone->num_large_objects_in_use;
-			stats->size_in_use = szone->num_bytes_in_large_objects;
-			stats->max_size_in_use = stats->size_allocated = stats->size_in_use;
-			return 1;
-		case 3:
-			stats->blocks_in_use = 0; // DEPRECATED szone->num_huge_entries;
-			stats->size_in_use = 0; // DEPRECATED szone->num_bytes_in_huge_objects;
-			stats->max_size_in_use = stats->size_allocated = 0;
-			return 1;
-	}
+		}
+
+		sa = (szone->medium_rack.num_regions - szone->medium_rack.num_regions_dealloc) * MEDIUM_REGION_SIZE;
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+		stats->blocks_in_use = t;
+		stats->size_in_use = u;
+		stats->size_allocated = sa;
+		stats->max_size_in_use = stats->size_allocated - s;
+		return 1;
+	}}
 	return 0;
+}
+
+static kern_return_t
+szone_statistics_task(task_t task, vm_address_t zone_address,
+					  memory_reader_t reader, malloc_statistics_t *stats)
+{
+	reader = !reader && task == mach_task_self() ? _malloc_default_reader : reader;
+
+	szone_t *szone;
+	kern_return_t err;
+
+	err = reader(task, zone_address, sizeof(szone_t), (void**)&szone);
+	if (err) return err;
+
+	size_t large;
+	size_t s = 0;
+	unsigned t = 0;
+	size_t u = 0;
+	mag_index_t mag_index;
+
+	magazine_t *mags;
+	err = reader(task, (vm_address_t)szone->tiny_rack.magazines, sizeof(magazine_t) * szone->tiny_rack.num_magazines, (void**)&mags);
+	if (err) return err;
+
+	for (mag_index = -1; mag_index < szone->tiny_rack.num_magazines; mag_index++) {
+		s += mags[mag_index].mag_bytes_free_at_start;
+		s += mags[mag_index].mag_bytes_free_at_end;
+		t += mags[mag_index].mag_num_objects;
+		u += mags[mag_index].mag_num_bytes_in_objects;
+	}
+
+	err = reader(task, (vm_address_t)szone->small_rack.magazines, sizeof(magazine_t) * szone->small_rack.num_magazines, (void**)&mags);
+	if (err) return err;
+
+	for (mag_index = -1; mag_index < szone->small_rack.num_magazines; mag_index++) {
+		s += mags[mag_index].mag_bytes_free_at_start;
+		s += mags[mag_index].mag_bytes_free_at_end;
+		t += mags[mag_index].mag_num_objects;
+		u += mags[mag_index].mag_num_bytes_in_objects;
+	}
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		for (mag_index = -1; mag_index < szone->medium_rack.num_magazines; mag_index++) {
+			s += szone->medium_rack.magazines[mag_index].mag_bytes_free_at_start;
+			s += szone->medium_rack.magazines[mag_index].mag_bytes_free_at_end;
+			t += szone->medium_rack.magazines[mag_index].mag_num_objects;
+			u += szone->medium_rack.magazines[mag_index].mag_num_bytes_in_objects;
+		}
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	large = szone->num_bytes_in_large_objects;
+
+	stats->blocks_in_use = t + szone->num_large_objects_in_use;
+	stats->size_in_use = u + large;
+	stats->max_size_in_use = stats->size_allocated =
+			(szone->tiny_rack.num_regions - szone->tiny_rack.num_regions_dealloc) * TINY_REGION_SIZE +
+			(szone->small_rack.num_regions - szone->small_rack.num_regions_dealloc) * SMALL_REGION_SIZE + large;
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		stats->max_size_in_use += (szone->medium_rack.num_regions -
+				szone->medium_rack.num_regions_dealloc) * MEDIUM_REGION_SIZE;
+	}
+#endif
+	// Now we account for the untouched areas
+	stats->max_size_in_use -= s;
+
+	return KERN_SUCCESS;
 }
 
 static void
 szone_statistics(szone_t *szone, malloc_statistics_t *stats)
 {
-	size_t	large;
-
-	size_t	s = 0;
-	unsigned	t = 0;
-	size_t	u = 0;
-	mag_index_t mag_index;
-
-	for (mag_index = -1; mag_index < szone->num_tiny_magazines; mag_index++) {
-		s += szone->tiny_magazines[mag_index].mag_bytes_free_at_start;
-		s += szone->tiny_magazines[mag_index].mag_bytes_free_at_end;
-		t += szone->tiny_magazines[mag_index].mag_num_objects;
-		u += szone->tiny_magazines[mag_index].mag_num_bytes_in_objects;
-	}
-
-	for (mag_index = -1; mag_index < szone->num_small_magazines; mag_index++) {
-		s += szone->small_magazines[mag_index].mag_bytes_free_at_start;
-		s += szone->small_magazines[mag_index].mag_bytes_free_at_end;
-		t += szone->small_magazines[mag_index].mag_num_objects;
-		u += szone->small_magazines[mag_index].mag_num_bytes_in_objects;
-	}
-
-	large = szone->num_bytes_in_large_objects + 0; // DEPRECATED szone->num_bytes_in_huge_objects;
-
-	stats->blocks_in_use = t + szone->num_large_objects_in_use + 0; // DEPRECATED szone->num_huge_entries;
-	stats->size_in_use = u + large;
-	stats->max_size_in_use = stats->size_allocated =
-	(szone->num_tiny_regions - szone->num_tiny_regions_dealloc) * TINY_REGION_SIZE +
-	(szone->num_small_regions - szone->num_small_regions_dealloc) * SMALL_REGION_SIZE + large;
-	// Now we account for the untouched areas
-	stats->max_size_in_use -= s;
-}
-
-static void *
-legacy_zeroing_large_malloc(szone_t *szone, size_t size) {
-	if (size > LARGE_THRESHOLD) // Leopard and earlier returned a ZFOD range, so ...
-		return szone_calloc(szone, 1, size); // Clear to zero always, ham-handedly touching in each page
-	else
-		return szone_malloc(szone, size);
-}
-
-static void *
-legacy_zeroing_large_valloc(szone_t *szone, size_t size) {
-	void *p = szone_valloc(szone, size);
-
-	// Leopard and earlier returned a ZFOD range, so ...
-	memset(p, 0, size); // Clear to zero always, ham-handedly touching in each page
-	return p;
-}
-
-void zeroify_scalable_zone(malloc_zone_t *zone)
-{
-	szone_t	*szone = (szone_t *)zone;
-
-	if (szone) {
-		mprotect(szone, sizeof(szone->basic_zone), PROT_READ | PROT_WRITE);
-		szone->basic_zone.malloc = (void *)legacy_zeroing_large_malloc;
-		szone->basic_zone.valloc = (void *)legacy_zeroing_large_valloc;
-		mprotect(szone, sizeof(szone->basic_zone), PROT_READ);
-	}
-}
-
-static const struct malloc_introspection_t szone_introspect = {
-	(void *)szone_ptr_in_use_enumerator,
-	(void *)szone_good_size,
-	(void *)szone_check,
-	(void *)szone_print,
-	szone_log,
-	(void *)szone_force_lock,
-	(void *)szone_force_unlock,
-	(void *)szone_statistics,
-	(void *)szone_locked,
-	NULL, NULL, NULL, NULL, /* Zone enumeration version 7 and forward. */
+	szone_statistics_task(mach_task_self(), (vm_address_t)szone, NULL, stats);
+}
+
+const struct malloc_introspection_t szone_introspect = {
+		(void *)szone_ptr_in_use_enumerator, (void *)szone_good_size, (void *)szone_check, (void *)szone_print_self, szone_log,
+		(void *)szone_force_lock, (void *)szone_force_unlock, (void *)szone_statistics, (void *)szone_locked, NULL, NULL, NULL,
+		NULL, /* Zone enumeration version 7 and forward. */
+		(void *)szone_reinit_lock, // reinit_lock version 9 and forward
+		(void *)szone_print_task,  // print task, version 11 and forward
+		(void *)szone_statistics_task // stats for task, version 12 and forward
 }; // marked as const to spare the DATA section
 
-malloc_zone_t *
-create_scalable_zone(size_t initial_size, unsigned debug_flags)
-{
-	szone_t	*szone;
-	uint64_t	hw_memsize = 0;
+szone_t *
+create_scalable_szone(size_t initial_size, unsigned debug_flags)
+{
+	szone_t *szone;
 
 #if defined(__i386__) || defined(__x86_64__)
 	if (_COMM_PAGE_VERSION_REQD > (*((uint16_t *)_COMM_PAGE_VERSION))) {
-		malloc_printf("*** ERROR - comm page version mismatch.\n");
-		exit(-1);
+		MALLOC_REPORT_FATAL_ERROR((*((uint16_t *)_COMM_PAGE_VERSION)), "comm page version mismatch");
 	}
 #endif
 
 	/* get memory for the zone. */
-	szone = allocate_pages(NULL, SZONE_PAGED_SIZE, 0, 0, VM_MEMORY_MALLOC);
-	if (!szone)
+	szone = mvm_allocate_pages(SZONE_PAGED_SIZE, 0, DISABLE_ASLR, VM_MEMORY_MALLOC);
+	if (!szone) {
 		return NULL;
-
-	/* set up the szone structure */
+	}
+
+/* set up the szone structure */
 #if 0
 #warning CHECK_REGIONS enabled
 	debug_flags |= CHECK_REGIONS;
@@ -7613,101 +1671,67 @@
 #warning LOG enabled
 	szone->log_address = ~0;
 #endif
-	szone->trg[0].nextgen = &(szone->trg[1]);
-	szone->trg[1].nextgen = &(szone->trg[0]);
-	szone->tiny_region_generation = &(szone->trg[0]);
-
-	szone->tiny_region_generation->hashed_regions = szone->initial_tiny_regions;
-	szone->tiny_region_generation->num_regions_allocated = INITIAL_NUM_REGIONS;
-	szone->tiny_region_generation->num_regions_allocated_shift = INITIAL_NUM_REGIONS_SHIFT;
-
-	szone->srg[0].nextgen = &(szone->srg[1]);
-	szone->srg[1].nextgen = &(szone->srg[0]);
-	szone->small_region_generation = &(szone->srg[0]);
-
-	szone->small_region_generation->hashed_regions = szone->initial_small_regions;
-	szone->small_region_generation->num_regions_allocated = INITIAL_NUM_REGIONS;
-	szone->small_region_generation->num_regions_allocated_shift = INITIAL_NUM_REGIONS_SHIFT;
-
-
-	/*
-	 * Initialize variables that size the free list for SMALL allocations based
-	 * upon the amount of memory in the system.  Switch to a larger number of
-	 * free list entries at 1GB.
-	 */
-#if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__arm64__)
-	if ((hw_memsize = *(uint64_t *)(uintptr_t)_COMM_PAGE_MEMORY_SIZE) >= (1ULL << 30))
-#else
-		size_t	uint64_t_size = sizeof(hw_memsize);
-
-	if (0 == sysctlbyname("hw.memsize", &hw_memsize, &uint64_t_size, 0, 0) &&
-		hw_memsize >= (1ULL << 30))
-#endif
-	{
-		szone->is_largemem = 1;
-		szone->num_small_slots = NUM_SMALL_SLOTS_LARGEMEM;
-		szone->large_threshold = LARGE_THRESHOLD_LARGEMEM;
-		szone->vm_copy_threshold = VM_COPY_THRESHOLD_LARGEMEM;
-	} else {
-		szone->is_largemem = 0;
-		szone->num_small_slots = NUM_SMALL_SLOTS;
-		szone->large_threshold = LARGE_THRESHOLD;
-		szone->vm_copy_threshold = VM_COPY_THRESHOLD;
-	}
-#if LARGE_CACHE
-	szone->large_entry_cache_reserve_limit =
-	hw_memsize >> 10; // madvise(..., MADV_REUSABLE) death-row arrivals above this threshold [~0.1%]
-
-	/* <rdar://problem/6610904> Reset protection when returning a previous large allocation? */
-	int32_t libSystemVersion  = NSVersionOfLinkTimeLibrary("System");
-	if ((-1 != libSystemVersion) && ((libSystemVersion >> 16) < 112) /* CFSystemVersionSnowLeopard */)
-		szone->large_legacy_reset_mprotect = TRUE;
-	else
-		szone->large_legacy_reset_mprotect = FALSE;
-#endif
-
-	// Prepare ASLR
-#if __i386__ || __x86_64__ || __arm64__ || TARGET_OS_EMBEDDED
-#if __i386__
-	uintptr_t stackbase = 0x8fe00000;
-	int entropic_bits = 3;
-#elif __x86_64__
-	uintptr_t stackbase = USRSTACK64;
-	int entropic_bits = 16;
-#elif __arm64__
-	uintptr_t stackbase = USRSTACK64;
-	int entropic_bits = 7;
-#else
-	uintptr_t stackbase = USRSTACK;
-	int entropic_bits = 3;
-#endif
-
-	// assert(((1 << entropic_bits) - 1) << SMALL_BLOCKS_ALIGN < (stackbase - MAXSSIZ - ENTROPIC_KABILLION));
-
-	if (0 != _dyld_get_image_slide((const struct mach_header*)_NSGetMachExecuteHeader())) {
-		if (0 == entropic_address) {
-			uintptr_t t = stackbase - MAXSSIZ - ((uintptr_t) (malloc_entropy[1] & ((1 << entropic_bits) - 1)) << SMALL_BLOCKS_ALIGN);
-			(void)__sync_bool_compare_and_swap(&entropic_limit, 0, t); // Just one initialization please
-			(void)__sync_bool_compare_and_swap(&entropic_address, 0, t - ENTROPIC_KABILLION); // Just one initialization please
-		}
+
+	if (mvm_aslr_enabled()) {
 		debug_flags &= ~DISABLE_ASLR;
 	} else {
-		// zero slide when ASLR has been disabled by boot-arg. Eliminate cloaking.
-		malloc_entropy[0] = 0;
-		malloc_entropy[1] = 0;
 		debug_flags |= DISABLE_ASLR;
 	}
 
-#else
-	malloc_entropy[0] = 0;
-	malloc_entropy[1] = 0;
-	debug_flags |= DISABLE_ASLR;
+#if CONFIG_MEDIUM_ALLOCATOR || CONFIG_LARGE_CACHE
+	uint64_t memsize = platform_hw_memsize();
+#endif // CONFIG_MEDIUM_ALLOCATOR || CONFIG_LARGE_CACHE
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	szone->is_medium_engaged = (magazine_medium_enabled &&
+			(memsize >= magazine_medium_active_threshold));
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+	// Query the number of configured processors.
+	// Uniprocessor case gets just one tiny and one small magazine (whose index is zero). This gives
+	// the same behavior as the original scalable malloc. MP gets per-CPU magazines
+	// that scale (way) better.
+	unsigned int max_mags = mag_max_magazines();
+	uint32_t num_magazines = (max_mags > 1) ? MIN(max_mags, TINY_MAX_MAGAZINES) : 1;
+	rack_init(&szone->tiny_rack, RACK_TYPE_TINY, num_magazines, debug_flags);
+	rack_init(&szone->small_rack, RACK_TYPE_SMALL, num_magazines, debug_flags);
+
+#if CONFIG_MEDIUM_ALLOCATOR
+	if (szone->is_medium_engaged) {
+		unsigned max_medium_mags = mag_max_medium_magazines();
+		uint32_t num_medium_mags = (max_medium_mags > 1) ?
+				MIN(max_medium_mags, TINY_MAX_MAGAZINES) : 1;
+		rack_init(&szone->medium_rack, RACK_TYPE_MEDIUM, num_medium_mags,
+				debug_flags);
+	}
+#endif // CONFIG_MEDIUM_ALLOCATOR
+
+#if CONFIG_LARGE_CACHE
+	if (large_cache_enabled) {
+		// madvise(..., MADV_REUSABLE) death-row arrivals above this threshold [~0.1%]
+		szone->large_entry_cache_reserve_limit = (size_t)(memsize >> 10);
+		if (memsize >= magazine_large_expanded_cache_threshold) {
+			szone->large_cache_depth = LARGE_ENTRY_CACHE_SIZE_HIGH;
+			szone->large_cache_entry_limit = LARGE_ENTRY_SIZE_ENTRY_LIMIT_HIGH;
+		} else {
+			szone->large_cache_depth = LARGE_ENTRY_CACHE_SIZE_LOW;
+			szone->large_cache_entry_limit = LARGE_ENTRY_SIZE_ENTRY_LIMIT_LOW;
+		}
+
+		/* <rdar://problem/6610904> Reset protection when returning a previous large allocation? */
+		int32_t libSystemVersion = NSVersionOfLinkTimeLibrary("System");
+		if ((-1 != libSystemVersion) && ((libSystemVersion >> 16) < 112) /* CFSystemVersionSnowLeopard */) {
+			szone->large_legacy_reset_mprotect = TRUE;
+		} else {
+			szone->large_legacy_reset_mprotect = FALSE;
+		}
+	}
 #endif
 
 	// Initialize the security token.
 	szone->cookie = (uintptr_t)malloc_entropy[0];
 
-	szone->basic_zone.version = 8;
+	szone->basic_zone.version = 12;
 	szone->basic_zone.size = (void *)szone_size;
 	szone->basic_zone.malloc = (void *)szone_malloc;
 	szone->basic_zone.calloc = (void *)szone_calloc;
@@ -7721,680 +1745,28 @@
 	szone->basic_zone.memalign = (void *)szone_memalign;
 	szone->basic_zone.free_definite_size = (void *)szone_free_definite_size;
 	szone->basic_zone.pressure_relief = (void *)szone_pressure_relief;
-
-	szone->basic_zone.reserved1 = 0; /* Set to zero once and for all as required by CFAllocator. */
-	szone->basic_zone.reserved2 = 0; /* Set to zero once and for all as required by CFAllocator. */
-	mprotect(szone, sizeof(szone->basic_zone), PROT_READ); /* Prevent overwriting the function pointers in basic_zone. */
+	szone->basic_zone.claimed_address = (void *)szone_claimed_address;
+
+	/* Set to zero once and for all as required by CFAllocator. */
+	szone->basic_zone.reserved1 = 0;
+	/* Set to zero once and for all as required by CFAllocator. */
+	szone->basic_zone.reserved2 = 0;
+
+	/* Prevent overwriting the function pointers in basic_zone. */
+	mprotect(szone, sizeof(szone->basic_zone), PROT_READ);
 
 	szone->debug_flags = debug_flags;
 	_malloc_lock_init(&szone->large_szone_lock);
 
-#if defined(__ppc__) || defined(__ppc64__)
-	/*
-	 * In the interest of compatibility for PPC applications executing via Rosetta,
-	 * arrange to zero-fill allocations as occurred by side effect in Leopard and earlier.
-	 */
-	zeroify_scalable_zone((malloc_zone_t *)szone);
-#endif
-
 	szone->cpu_id_key = -1UL; // Unused.
 
-	// Query the number of configured processors.
-	// Uniprocessor case gets just one tiny and one small magazine (whose index is zero). This gives
-	// the same behavior as the original scalable malloc. MP gets per-CPU magazines
-	// that scale (way) better.
-#if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__arm64__)
-	int nproc = *(uint8_t *)(uintptr_t)_COMM_PAGE_NCPUS;
-#else
-	int nproc = sysconf(_SC_NPROCESSORS_CONF);
-#endif
-	szone->num_tiny_magazines = (nproc > 1) ? MIN(nproc, TINY_MAX_MAGAZINES) : 1;
-
-	// FIXME vm_allocate() based on number of configured CPUs
-	magazine_t *tiny_magazines = allocate_pages(NULL, TINY_MAGAZINE_PAGED_SIZE, 0,
-												SCALABLE_MALLOC_ADD_GUARD_PAGES, VM_MEMORY_MALLOC);
-	if (NULL == tiny_magazines)
-		return NULL;
-
-	szone->tiny_magazines = &(tiny_magazines[1]); // szone->tiny_magazines[-1] is the Depot
-
-	// The magazines are indexed in [0 .. (num_tiny_magazines - 1)]
-	// Find the smallest power of 2 that exceeds (num_tiny_magazines - 1)
-	szone->num_tiny_magazines_mask_shift = 0;
-	int i = 1;
-	while( i <= (szone->num_tiny_magazines - 1) ) {
-		szone->num_tiny_magazines_mask_shift++;
-		i <<= 1;
-	}
-
-	// Now if i <= TINY_MAX_MAGAZINES we'll never access tiny_magazines[] out of bounds.
-	if (i > TINY_MAX_MAGAZINES) {
-		malloc_printf("*** FATAL ERROR - magazine mask exceeds allocated magazines.\n");
-		exit(-1);
-	}
-
-	// Reduce i by 1 to obtain a mask covering [0 .. (num_tiny_magazines - 1)]
-	szone->num_tiny_magazines_mask = i - 1; // A mask used for hashing to a magazine index (and a safety aid)
-	szone->last_tiny_advise = 0;
-
-	// Init the tiny_magazine locks
-	_malloc_lock_init(&szone->tiny_regions_lock);
-	_malloc_lock_init(&szone->tiny_magazines[DEPOT_MAGAZINE_INDEX].magazine_lock);
-	for (i = 0; i < szone->num_tiny_magazines; ++i) {
-		_malloc_lock_init(&szone->tiny_magazines[i].magazine_lock);
-	}
-
-	szone->num_small_magazines = (nproc > 1) ? MIN(nproc, SMALL_MAX_MAGAZINES) : 1;
-
-	// FIXME vm_allocate() based on number of configured CPUs
-	magazine_t *small_magazines = allocate_pages(NULL, SMALL_MAGAZINE_PAGED_SIZE, 0,
-												 SCALABLE_MALLOC_ADD_GUARD_PAGES, VM_MEMORY_MALLOC);
-	if (NULL == small_magazines)
-		return NULL;
-
-	szone->small_magazines = &(small_magazines[1]); // szone->small_magazines[-1] is the Depot
-
-	// The magazines are indexed in [0 .. (num_small_magazines - 1)]
-	// Find the smallest power of 2 that exceeds (num_small_magazines - 1)
-	szone->num_small_magazines_mask_shift = 0;
-	while( i <= (szone->num_small_magazines - 1) ) {
-		szone->num_small_magazines_mask_shift++;
-		i <<= 1;
-	}
-
-	// Now if i <= SMALL_MAX_MAGAZINES we'll never access small_magazines[] out of bounds.
-	if (i > SMALL_MAX_MAGAZINES) {
-		malloc_printf("*** FATAL ERROR - magazine mask exceeds allocated magazines.\n");
-		exit(-1);
-	}
-
-	// Reduce i by 1 to obtain a mask covering [0 .. (num_small_magazines - 1)]
-	szone->num_small_magazines_mask = i - 1; // A mask used for hashing to a magazine index (and a safety aid)
-	szone->last_small_advise = 0;
-
-	// Init the small_magazine locks
-	_malloc_lock_init(&szone->small_regions_lock);
-	_malloc_lock_init(&szone->small_magazines[DEPOT_MAGAZINE_INDEX].magazine_lock);
-	for (i = 0; i < szone->num_small_magazines; ++i) {
-		_malloc_lock_init(&szone->small_magazines[i].magazine_lock);
-	}
-
 	CHECK(szone, __PRETTY_FUNCTION__);
-	return (malloc_zone_t *)szone;
-}
-
-//
-// purgeable zones have their own "large" allocation pool, but share "tiny" and "large"
-// heaps with a helper_zone identified in the call to create_purgeable_zone()
-//
-static size_t
-purgeable_size(szone_t *szone, const void *ptr)
-{
-	// Only claim our large allocations, leave the shared tiny/small for the helper zone to claim.
-	return szone_size_try_large(szone, ptr);
-}
-
-static void *
-purgeable_malloc(szone_t *szone, size_t size) {
-	if (size <= szone->large_threshold)
-		return szone_malloc(szone->helper_zone, size);
-	else
-		return szone_malloc(szone, size);
-}
-
-static void *
-purgeable_calloc(szone_t *szone, size_t num_items, size_t size)
-{
-	size_t total_bytes = num_items * size;
-
-	// Check for overflow of integer multiplication
-	if (num_items > 1) {
-#if __LP64__ /* size_t is uint64_t */
-		if ((num_items | size) & 0xffffffff00000000ul) {
-			// num_items or size equals or exceeds sqrt(2^64) == 2^32, appeal to wider arithmetic
-			__uint128_t product = ((__uint128_t)num_items) * ((__uint128_t)size);
-			if ((uint64_t)(product >> 64)) // compiles to test on upper register of register pair
-				return NULL;
-		}
-#else /* size_t is uint32_t */
-		if ((num_items | size) & 0xffff0000ul) {
-			// num_items or size equals or exceeds sqrt(2^32) == 2^16, appeal to wider arithmetic
-			uint64_t product = ((uint64_t)num_items) * ((uint64_t)size);
-			if ((uint32_t)(product >> 32)) // compiles to test on upper register of register pair
-				return NULL;
-		}
-#endif
-	}
-
-	if (total_bytes <= szone->large_threshold)
-		return szone_calloc(szone->helper_zone, 1, total_bytes);
-	else
-		return szone_calloc(szone, 1, total_bytes);
-}
-
-static void *
-purgeable_valloc(szone_t *szone, size_t size)
-{
-	if (size <= szone->large_threshold)
-		return szone_valloc(szone->helper_zone, size);
-	else
-		return szone_valloc(szone, size);
-}
-
-static void
-purgeable_free(szone_t *szone, void *ptr)
-{
-	large_entry_t	*entry;
-
-	SZONE_LOCK(szone);
-	entry = large_entry_for_pointer_no_lock(szone, ptr);
-	SZONE_UNLOCK(szone);
-	if (entry) {
-		return free_large(szone, ptr);
-	} else {
-		return szone_free(szone->helper_zone, ptr);
-	}
-}
-
-static void
-purgeable_free_definite_size(szone_t *szone, void *ptr, size_t size)
-{
-	if (size <= szone->large_threshold)
-		return szone_free_definite_size(szone->helper_zone, ptr, size);
-	else
-		return szone_free_definite_size(szone, ptr, size);
-}
-
-static void *
-purgeable_realloc(szone_t *szone, void *ptr, size_t new_size)
-{
-	size_t old_size;
-
-	if (NULL == ptr) {
-		// If ptr is a null pointer, realloc() shall be equivalent to malloc() for the specified size.
-		return purgeable_malloc(szone, new_size);
-	} else if (0 == new_size) {
-		// If size is 0 and ptr is not a null pointer, the object pointed to is freed.
-		purgeable_free(szone, ptr);
-		// If size is 0, either a null pointer or a unique pointer that can be successfully passed
-		// to free() shall be returned.
-		return purgeable_malloc(szone, 1);
-	}
-
-	old_size = purgeable_size(szone, ptr); // Now ptr can be safely size()'d
-	if (!old_size)
-		old_size = szone_size(szone->helper_zone, ptr);
-
-	if (!old_size) {
-		szone_error(szone, 1, "pointer being reallocated was not allocated", ptr, NULL);
-		return NULL;
-	}
-
-	// Distinguish 4 cases: {oldsize, newsize} x { <= , > large_threshold }
-	// and deal with the allocation crossing from the purgeable zone to the helper zone and vice versa.
-	if (old_size <= szone->large_threshold) {
-		if (new_size <= szone->large_threshold)
-			return szone_realloc(szone->helper_zone, ptr, new_size);
-		else {
-			// allocation crosses from helper to purgeable zone
-			void * new_ptr = purgeable_malloc(szone, new_size);
-			if (new_ptr) {
-				memcpy(new_ptr, ptr, old_size);
-				szone_free_definite_size(szone->helper_zone, ptr, old_size);
-			}
-			return new_ptr; // in state VM_PURGABLE_NONVOLATILE
-		}
-	} else {
-		if (new_size <= szone->large_threshold) {
-			// allocation crosses from purgeable to helper zone
-			void * new_ptr = szone_malloc(szone->helper_zone, new_size);
-			if (new_ptr) {
-				memcpy(new_ptr, ptr, new_size);
-				purgeable_free_definite_size(szone, ptr, old_size);
-			}
-			return new_ptr;
-		} else {
-			void * new_ptr = purgeable_malloc(szone, new_size);
-			if (new_ptr) {
-				memcpy(new_ptr, ptr, MIN(old_size, new_size));
-				purgeable_free_definite_size(szone, ptr, old_size);
-			}
-			return new_ptr; // in state VM_PURGABLE_NONVOLATILE
-		}
-	}
-	/* NOTREACHED */
-}
-
-static void
-purgeable_destroy(szone_t *szone)
-{
-	/* destroy large entries */
-	size_t index = szone->num_large_entries;
-	large_entry_t	*large;
-	vm_range_t		range_to_deallocate;
-	
-	while (index--) {
-		large = szone->large_entries + index;
-		if (large->address) {
-			// we deallocate_pages, including guard pages
-			deallocate_pages(szone, (void *)(large->address), large->size, szone->debug_flags);
-		}
-	}
-	large_entries_free_no_lock(szone, szone->large_entries, szone->num_large_entries, &range_to_deallocate);
-	if (range_to_deallocate.size)
-		deallocate_pages(szone, (void *)range_to_deallocate.address, (size_t)range_to_deallocate.size, 0);
-	
-	/* Now destroy the separate szone region */
-	deallocate_pages(szone, (void *)szone, SZONE_PAGED_SIZE, 0);
-}
-
-static unsigned
-purgeable_batch_malloc(szone_t *szone, size_t size, void **results, unsigned count)
-{
-	return szone_batch_malloc(szone->helper_zone, size, results, count);
-}
-
-static void
-purgeable_batch_free(szone_t *szone, void **to_be_freed, unsigned count)
-{
-	return szone_batch_free(szone->helper_zone, to_be_freed, count);
-}
-
-static void *
-purgeable_memalign(szone_t *szone, size_t alignment, size_t size)
-{
-	if (size <= szone->large_threshold)
-		return szone_memalign(szone->helper_zone, alignment, size);
-	else
-		return szone_memalign(szone, alignment, size);
-}
-
-static kern_return_t
-purgeable_ptr_in_use_enumerator(task_t task, void *context, unsigned type_mask, vm_address_t zone_address, 
-								memory_reader_t reader, vm_range_recorder_t recorder)
-{
-	szone_t		*szone;
-	kern_return_t	err;
-	
-	if (!reader) reader = _szone_default_reader;
-	
-	err = reader(task, zone_address, sizeof(szone_t), (void **)&szone);
-	if (err) return err;
-	
-	err = large_in_use_enumerator(task, context, type_mask, 
-								  (vm_address_t)szone->large_entries, szone->num_large_entries, reader, recorder);
-	return err;
-}
-
-static size_t
-purgeable_good_size(szone_t *szone, size_t size)
-{
-	if (size <= szone->large_threshold)
-		return szone_good_size(szone->helper_zone, size);
-	else
-		return szone_good_size(szone, size);
-}
-
-static boolean_t
-purgeable_check(szone_t *szone)
-{
-	return 1;
-}
-
-static void
-purgeable_print(szone_t *szone, boolean_t verbose)
-{
-	_malloc_printf(MALLOC_PRINTF_NOLOG | MALLOC_PRINTF_NOPREFIX,
-				   "Scalable zone %p: inUse=%u(%y) flags=%d\n",
-				   szone, szone->num_large_objects_in_use, szone->num_bytes_in_large_objects, szone->debug_flags);
-}
-
-static void
-purgeable_log(malloc_zone_t *zone, void *log_address)
-{
-	szone_t	*szone = (szone_t *)zone;
-	
-	szone->log_address = log_address;
-}
-
-static void
-purgeable_force_lock(szone_t *szone)
-{    
-	SZONE_LOCK(szone);
-}
-
-static void
-purgeable_force_unlock(szone_t *szone)
-{    
-	SZONE_UNLOCK(szone);
-}
-
-static void
-purgeable_statistics(szone_t *szone, malloc_statistics_t *stats)
-{
-	stats->blocks_in_use = szone->num_large_objects_in_use;
-	stats->size_in_use = stats->max_size_in_use = stats->size_allocated = szone->num_bytes_in_large_objects;
-}
-
-static boolean_t
-purgeable_locked(szone_t *szone) 
-{
-	int tookLock;
-	
-	tookLock = SZONE_TRY_LOCK(szone);
-	if (tookLock == 0)
-		return 1;
-	SZONE_UNLOCK(szone);
-	return 0;
-}
-
-static size_t
-purgeable_pressure_relief(szone_t *szone, size_t goal)
-{
-	return szone_pressure_relief(szone, goal) + szone_pressure_relief(szone->helper_zone, goal);
-}
-
-static const struct malloc_introspection_t purgeable_introspect = {
-	(void *)purgeable_ptr_in_use_enumerator,
-	(void *)purgeable_good_size,
-	(void *)purgeable_check,
-	(void *)purgeable_print,
-	purgeable_log,
-	(void *)purgeable_force_lock,
-	(void *)purgeable_force_unlock,
-	(void *)purgeable_statistics,
-	(void *)purgeable_locked,
-	NULL, NULL, NULL, NULL, /* Zone enumeration version 7 and forward. */
-}; // marked as const to spare the DATA section
-
-__attribute__((visibility("hidden")))
+	return szone;
+}
+
 malloc_zone_t *
-create_purgeable_zone(size_t initial_size, malloc_zone_t *malloc_default_zone, unsigned debug_flags)
-{
-	szone_t	*szone;
-	uint64_t	hw_memsize = 0;
-	
-	/* get memory for the zone. */
-	szone = allocate_pages(NULL, SZONE_PAGED_SIZE, 0, 0, VM_MEMORY_MALLOC);
-	if (!szone)
-		return NULL;
-	
-	/* set up the szone structure */
-#if 0
-#warning LOG enabled
-	szone->log_address = ~0;
-#endif
-	
-#if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__arm64__)
-	hw_memsize = *(uint64_t *)(uintptr_t)_COMM_PAGE_MEMORY_SIZE;
-#else
-	size_t	uint64_t_size = sizeof(hw_memsize);
-	
-	sysctlbyname("hw.memsize", &hw_memsize, &uint64_t_size, 0, 0);
-#endif
-
-	szone->trg[0].nextgen = &(szone->trg[1]);
-	szone->trg[1].nextgen = &(szone->trg[0]);
-	szone->tiny_region_generation = &(szone->trg[0]);
-
-	szone->tiny_region_generation->hashed_regions = szone->initial_tiny_regions;
-	szone->tiny_region_generation->num_regions_allocated = INITIAL_NUM_REGIONS;
-	szone->tiny_region_generation->num_regions_allocated_shift = INITIAL_NUM_REGIONS_SHIFT;
-
-	szone->srg[0].nextgen = &(szone->srg[1]);
-	szone->srg[1].nextgen = &(szone->srg[0]);
-	szone->small_region_generation = &(szone->srg[0]);
-
-	szone->small_region_generation->hashed_regions = szone->initial_small_regions;
-	szone->small_region_generation->num_regions_allocated = INITIAL_NUM_REGIONS;
-	szone->small_region_generation->num_regions_allocated_shift = INITIAL_NUM_REGIONS_SHIFT;
-
-	/* Purgeable zone does not participate in the adaptive "largemem" sizing. */
-	szone->is_largemem = 0;
-	szone->large_threshold = LARGE_THRESHOLD;
-	szone->vm_copy_threshold = VM_COPY_THRESHOLD;
-	
-#if LARGE_CACHE
-	szone->large_entry_cache_reserve_limit = 
-	hw_memsize >> 10; // madvise(..., MADV_REUSABLE) death-row arrivals above this threshold [~0.1%]
-	
-	/* <rdar://problem/6610904> Reset protection when returning a previous large allocation? */
-	int32_t libSystemVersion  = NSVersionOfLinkTimeLibrary("System");
-	if ((-1 != libSystemVersion) && ((libSystemVersion >> 16) < 112) /* CFSystemVersionSnowLeopard */)
-		szone->large_legacy_reset_mprotect = TRUE;
-	else
-		szone->large_legacy_reset_mprotect = FALSE;
-#endif
-	
-	szone->basic_zone.version = 8;
-	szone->basic_zone.size = (void *)purgeable_size;
-	szone->basic_zone.malloc = (void *)purgeable_malloc;
-	szone->basic_zone.calloc = (void *)purgeable_calloc;
-	szone->basic_zone.valloc = (void *)purgeable_valloc;
-	szone->basic_zone.free = (void *)purgeable_free;
-	szone->basic_zone.realloc = (void *)purgeable_realloc;
-	szone->basic_zone.destroy = (void *)purgeable_destroy;
-	szone->basic_zone.batch_malloc = (void *)purgeable_batch_malloc;
-	szone->basic_zone.batch_free = (void *)purgeable_batch_free;
-	szone->basic_zone.introspect = (struct malloc_introspection_t *)&purgeable_introspect;
-	szone->basic_zone.memalign = (void *)purgeable_memalign;
-	szone->basic_zone.free_definite_size = (void *)purgeable_free_definite_size;
-	szone->basic_zone.pressure_relief = (void *)purgeable_pressure_relief;
-	
-	szone->basic_zone.reserved1 = 0; /* Set to zero once and for all as required by CFAllocator. */
-	szone->basic_zone.reserved2 = 0; /* Set to zero once and for all as required by CFAllocator. */
-	mprotect(szone, sizeof(szone->basic_zone), PROT_READ); /* Prevent overwriting the function pointers in basic_zone. */
-	
-	szone->debug_flags = debug_flags | SCALABLE_MALLOC_PURGEABLE;
-	
-	/* Purgeable zone does not support SCALABLE_MALLOC_ADD_GUARD_PAGES. */
-	if (szone->debug_flags & SCALABLE_MALLOC_ADD_GUARD_PAGES) {
-		_malloc_printf(ASL_LEVEL_INFO, "purgeable zone does not support guard pages\n");
-		szone->debug_flags &= ~SCALABLE_MALLOC_ADD_GUARD_PAGES;
-	}
-	
-	_malloc_lock_init(&szone->large_szone_lock);
-	
-	szone->helper_zone = (struct szone_s *)malloc_default_zone;
-	
-	CHECK(szone, __PRETTY_FUNCTION__);
-	return (malloc_zone_t *)szone;
-}
-
-/*
- * For use by CheckFix: create a new zone whose behavior is, apart from
- * the use of death-row and per-CPU magazines, that of Leopard.
- */
-static NOINLINE void *
-legacy_valloc(szone_t *szone, size_t size)
-{
-	void	*ptr;
-	size_t num_kernel_pages;
-	
-	num_kernel_pages = round_page_quanta(size) >> vm_page_quanta_shift;
-	ptr = large_malloc(szone, num_kernel_pages, 0, TRUE);
-#if DEBUG_MALLOC
-	if (LOG(szone, ptr))
-		malloc_printf("legacy_valloc returned %p\n", ptr);
-#endif
-	return ptr;
-}
-
-__attribute__((visibility("hidden")))
-malloc_zone_t *
-create_legacy_scalable_zone(size_t initial_size, unsigned debug_flags)
-{
-	malloc_zone_t *mzone = create_scalable_zone(initial_size, debug_flags);
-	szone_t	*szone = (szone_t *)mzone;
-	
-	if (!szone)
-		return NULL;
-	
-	szone->is_largemem = 0;
-	szone->num_small_slots = NUM_SMALL_SLOTS;
-	szone->large_threshold = LARGE_THRESHOLD;
-	szone->vm_copy_threshold = VM_COPY_THRESHOLD;
-	
-	mprotect(szone, sizeof(szone->basic_zone), PROT_READ | PROT_WRITE);
-	szone->basic_zone.valloc = (void *)legacy_valloc;
-	szone->basic_zone.free_definite_size = NULL;
-	mprotect(szone, sizeof(szone->basic_zone), PROT_READ);
-	
-	return mzone;
-}
-
-/********* Support code for emacs unexec ************/
-
-/* History of freezedry version numbers:
- *
- * 1) Old malloc (before the scalable malloc implementation in this file
- *    existed).
- * 2) Original freezedrying code for scalable malloc.  This code was apparently
- *    based on the old freezedrying code and was fundamentally flawed in its
- *    assumption that tracking allocated memory regions was adequate to fake
- *    operations on freezedried memory.  This doesn't work, since scalable
- *    malloc does not store flags in front of large page-aligned allocations.
- * 3) Original szone-based freezedrying code.
- * 4) Fresher malloc with tiny zone
- * 5) 32/64bit compatible malloc
- * 6) Metadata within 1MB and 8MB region for tiny and small
- *
- * No version backward compatibility is provided, but the version number does
- * make it possible for malloc_jumpstart() to return an error if the application
- * was freezedried with an older version of malloc.
- */
-#define MALLOC_FREEZEDRY_VERSION 6
-
-typedef struct {
-	unsigned	version;
-	unsigned	nszones;
-	szone_t	*szones;
-} malloc_frozen;
-
-static void *
-frozen_malloc(szone_t *zone, size_t new_size)
-{
-	return malloc(new_size);
-}
-
-static void *
-frozen_calloc(szone_t *zone, size_t num_items, size_t size)
-{
-	return calloc(num_items, size);
-}
-
-static void *
-frozen_valloc(szone_t *zone, size_t new_size)
-{
-	return valloc(new_size);
-}
-
-static void *
-frozen_realloc(szone_t *zone, void *ptr, size_t new_size)
-{
-	size_t	old_size = szone_size(zone, ptr);
-	void	*new_ptr;
-	
-	if (new_size <= old_size) {
-		return ptr;
-	}
-	new_ptr = malloc(new_size);
-	if (old_size > 0) {
-		memcpy(new_ptr, ptr, old_size);
-	}
-	return new_ptr;
-}
-
-static void
-frozen_free(szone_t *zone, void *ptr)
-{
-}
-
-static void
-frozen_destroy(szone_t *zone)
-{
-}
-
-/********* Pseudo-private API for emacs unexec ************/
-
-/*
- * malloc_freezedry() records all of the szones in use, so that they can be
- * partially reconstituted by malloc_jumpstart().  Due to the differences
- * between reconstituted memory regions and those created by the szone code,
- * care is taken not to reallocate from the freezedried memory, except in the
- * case of a non-growing realloc().
- *
- * Due to the flexibility provided by the zone registration mechanism, it is
- * impossible to implement generic freezedrying for any zone type.  This code
- * only handles applications that use the szone allocator, so malloc_freezedry()
- * returns 0 (error) if any non-szone zones are encountered.
- */
-
-uintptr_t
-malloc_freezedry(void)
-{
-	extern unsigned malloc_num_zones;
-	extern malloc_zone_t **malloc_zones;
-	malloc_frozen *data;
-	unsigned i;
-	
-	/* Allocate space in which to store the freezedry state. */
-	data = (malloc_frozen *) malloc(sizeof(malloc_frozen));
-	
-	/* Set freezedry version number so that malloc_jumpstart() can check for compatibility. */
-	data->version = MALLOC_FREEZEDRY_VERSION;
-	
-	/* Allocate the array of szone pointers. */
-	data->nszones = malloc_num_zones;
-	data->szones = (szone_t *) calloc(malloc_num_zones, sizeof(szone_t));
-	
-	/*
-	 * Fill in the array of szone structures.  They are copied rather than
-	 * referenced, since the originals are likely to be clobbered during malloc
-	 * initialization.
-	 */
-	for (i = 0; i < malloc_num_zones; i++) {
-		if (strcmp(malloc_zones[i]->zone_name, "DefaultMallocZone")) {
-			/* Unknown zone type. */
-			free(data->szones);
-			free(data);
-			return 0;
-		}
-		memcpy(&data->szones[i], malloc_zones[i], sizeof(szone_t));
-	}
-	
-	return((uintptr_t)data);
-}
-
-int
-malloc_jumpstart(uintptr_t cookie)
-{
-	malloc_frozen *data = (malloc_frozen *)cookie;
-	unsigned i;
-	
-	if (data->version != MALLOC_FREEZEDRY_VERSION) {
-		/* Unsupported freezedry version. */
-		return 1;
-	}
-	
-	for (i = 0; i < data->nszones; i++) {
-		/* Set function pointers.  Even the functions that stay the same must be
-		 * set, since there are no guarantees that they will be mapped to the
-		 * same addresses. */
-		data->szones[i].basic_zone.size = (void *) szone_size;
-		data->szones[i].basic_zone.malloc = (void *) frozen_malloc;
-		data->szones[i].basic_zone.calloc = (void *) frozen_calloc;
-		data->szones[i].basic_zone.valloc = (void *) frozen_valloc;
-		data->szones[i].basic_zone.free = (void *) frozen_free;
-		data->szones[i].basic_zone.realloc = (void *) frozen_realloc;
-		data->szones[i].basic_zone.destroy = (void *) frozen_destroy;
-		data->szones[i].basic_zone.introspect = (struct malloc_introspection_t *)&szone_introspect;
-		
-		/* Register the freezedried zone. */
-		malloc_zone_register(&data->szones[i].basic_zone);
-	}
-	
-	return 0;
+create_scalable_zone(size_t initial_size, unsigned debug_flags) {
+	return (malloc_zone_t *) create_scalable_szone(initial_size, debug_flags);
 }
 
 /* vim: set noet:ts=4:sw=4:cindent: */