Loading...
src/magazine_tiny.c libmalloc-166.200.60 /dev/null
--- libmalloc/libmalloc-166.200.60/src/magazine_tiny.c
+++ /dev/null
@@ -1,2418 +0,0 @@
-/*
- * Copyright (c) 2015 Apple Inc. All rights reserved.
- *
- * @APPLE_LICENSE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
- */
-
-#include "internal.h"
-
-// The address and size of the block in mag_last_free are combined. These
-// macros abstract construction of the combined value and extraction of the
-// size and pointer.
-#define TINY_MAG_LAST_FREE_FROM_PTR_AND_MSIZE(ptr, msize) (void *)(((uintptr_t)(ptr))|((msize_t)msize))
-#define TINY_PTR_FROM_MAG_LAST_FREE(x) (void *)(((uintptr_t)(x)) & ~(TINY_QUANTUM - 1))
-#define TINY_MSIZE_FROM_MAG_LAST_FREE(x) (msize_t)(((uintptr_t)(x)) & (TINY_QUANTUM - 1))
-
-// Adjusts the pointer part of mag_last_free by a given amount in bytes. Must be
-// a multiple of the quantum size (not checked).
-#define TINY_MAG_LAST_FREE_PTR_ADJUST_PTR(x, size) (x) = ((void *)(x) + (size))
-
-// Decrements the size part of mag_last_free by a given msize value. Must not
-// reduce the msize part below zero (not checked).
-#define TINY_MAG_LAST_FREE_PTR_DEC_MSIZE(x, msize_delta) (x) = ((void *)(x) - (msize_delta))
-
-static MALLOC_INLINE MALLOC_ALWAYS_INLINE
-mag_index_t
-tiny_mag_get_thread_index(void)
-{
-#if CONFIG_TINY_USES_HYPER_SHIFT
-	if (os_likely(_os_cpu_number_override == -1)) {
-		return _os_cpu_number() >> hyper_shift;
-	} else {
-		return _os_cpu_number_override >> hyper_shift;
-	}
-#else // CONFIG_SMALL_USES_HYPER_SHIFT
-	if (os_likely(_os_cpu_number_override == -1)) {
-		return _os_cpu_number();
-	} else {
-		return _os_cpu_number_override;
-	}
-#endif // CONFIG_SMALL_USES_HYPER_SHIFT
-}
-
-/*
- * 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 MALLOC_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_report(ASL_LEVEL_ERR, "set_tiny_meta_header_in_use() invariant broken %p %d\n", ptr, msize);
-	}
-	if ((unsigned)index + (unsigned)msize > 0x10000) {
-		malloc_report(ASL_LEVEL_ERR, "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_report(ASL_LEVEL_INFO, "setting header for tiny in_use %p : %d\n", ptr, msize);
-			malloc_report(ASL_LEVEL_INFO, "reading header for tiny %p : %d %d\n", ptr, mf, ff);
-		}
-	}
-#endif
-}
-
-static MALLOC_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 MALLOC_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 MALLOC_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_report(ASL_LEVEL_ERR, "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_report(ASL_LEVEL_INFO, "setting header for tiny free %p : %u\n", ptr, msize);
-		malloc_report(ASL_LEVEL_INFO, "reading header for tiny %p : %u %u\n", ptr, mf, ff);
-	}
-#endif
-}
-
-static MALLOC_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 MALLOC_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(rack_t *rack, magazine_t *tiny_mag_ptr, void *ptr, msize_t msize)
-{
-	grain_t slot = (!msize || (msize >= NUM_TINY_SLOTS)) ? NUM_TINY_SLOTS - 1 : msize - 1;
-	tiny_free_list_t *free_ptr = ptr;
-	tiny_free_list_t *free_head = tiny_mag_ptr->mag_free_list[slot].p;
-
-#if DEBUG_MALLOC
-	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in %s, ptr=%p, msize=%d\n", __FUNCTION__, ptr, msize);
-	}
-	if (((uintptr_t)ptr) & (TINY_QUANTUM - 1)) {
-		malloc_zone_error(rack->debug_flags, true, "tiny_free_list_add_ptr: Unaligned ptr: %p\n", ptr);
-	}
-#endif
-	set_tiny_meta_header_free(ptr, msize);
-	if (free_head) {
-#if DEBUG_MALLOC
-		if (free_list_unchecksum_ptr(szone, &free_head->previous)) {
-			malloc_zone_error(rack->debug_flags, true,
-					"tiny_free_list_add_ptr: Internal invariant broken (free_head->previous): "
-					"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)) {
-			malloc_zone_error(rack->debug_flags, true,
-					"tiny_free_list_add_ptr: Internal invariant broken (free_head is not a free pointer): "
-					"ptr=%p slot=%d free_head=%p\n", ptr, slot, (void *)free_head);
-		}
-#endif
-		free_head->previous.u = free_list_checksum_ptr(rack, free_ptr);
-	} else {
-		BITMAPV_SET(tiny_mag_ptr->mag_bitmap, slot);
-	}
-	free_ptr->previous.u = free_list_checksum_ptr(rack, NULL);
-	free_ptr->next.u = free_list_checksum_ptr(rack, free_head);
-
-	tiny_mag_ptr->mag_free_list[slot].p = 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(rack_t *rack, magazine_t *tiny_mag_ptr, void *ptr, msize_t msize)
-{
-	grain_t slot = (!msize || (msize >= NUM_TINY_SLOTS)) ? NUM_TINY_SLOTS - 1 : msize - 1;
-	tiny_free_list_t *free_ptr = ptr, *next, *previous;
-
-	next = free_list_unchecksum_ptr(rack, &free_ptr->next);
-	previous = free_list_unchecksum_ptr(rack, &free_ptr->previous);
-
-#if DEBUG_MALLOC
-	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "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) {
-			malloc_zone_error(rack->debug_flags, true,
-					"tiny_free_list_remove_ptr: Internal invariant broken (tiny_mag_ptr->mag_free_list[slot]): "
-					"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].p = next;
-		if (!next) {
-			BITMAPV_CLR(tiny_mag_ptr->mag_bitmap, slot);
-		}
-	} else {
-		// Check that the next pointer of "previous" points to free_ptr.
-		tiny_free_list_t *prev_next = free_list_unchecksum_ptr(rack, &previous->next);
-		if (prev_next != free_ptr) {
-			malloc_zone_error(rack->debug_flags, true,
-					"tiny_free_list_remove_ptr: Internal invariant broken (next ptr of prev): "
-					"ptr=%p, prev_next=%p\n", ptr, prev_next);
-			__builtin_unreachable(); // Always crashes in malloc_zone_error().
-		}
-
-		// We know free_ptr is already checksummed, so we don't need to do it
-		// again.
-		previous->next = free_ptr->next;
-	}
-	if (next) {
-		// Check that the previous pointer of "next" points to free_ptr.
-		tiny_free_list_t *next_prev = free_list_unchecksum_ptr(rack, &next->previous);
-		if (next_prev != free_ptr) {
-			malloc_zone_error(rack->debug_flags, true,
-					"tiny_free_list_remove_ptr: Internal invariant broken (prev ptr of next): "
-					"ptr=%p, next_prev=%p\n", ptr, next_prev);
-			__builtin_unreachable(); // Always crashes in malloc_zone_error().
-		}
-
-		// We know free_ptr is already checksummed, so we don't need to do it
-		// again.
-		next->previous = free_ptr->previous;
-	}
-}
-
-void
-tiny_finalize_region(rack_t *rack, 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(rack, 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(rack, tiny_mag_ptr, last_block, last_msize);
-		tiny_mag_ptr->mag_bytes_free_at_end = 0;
-	}
-
-#if CONFIG_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(rack, tiny_mag_ptr, next_block, next_msize);
-			last_msize += next_msize;
-		}
-
-		// splice last_block into the free list
-		tiny_free_list_add_ptr(rack, tiny_mag_ptr, last_block, last_msize);
-		tiny_mag_ptr->mag_bytes_free_at_start = 0;
-	}
-#endif
-
-	tiny_mag_ptr->mag_last_region = NULL;
-}
-
-int
-tiny_free_detach_region(rack_t *rack, 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_report(ASL_LEVEL_ERR, "*** 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(rack, tiny_mag_ptr, (void *)current, msize);
-		} else {
-			total_alloc++;
-		}
-		current += TINY_BYTES_FOR_MSIZE(msize);
-	}
-	return total_alloc;
-}
-
-size_t
-tiny_free_reattach_region(rack_t *rack, 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_report(ASL_LEVEL_ERR, "*** 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(rack, 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;
-
-void
-tiny_free_scan_madvise_free(rack_t *rack, 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_report(ASL_LEVEL_INFO, "*** 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_kernel(start + sizeof(tiny_free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_kernel(start + TINY_REGION_SIZE - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				advisory[advisories].pnum = (pgLo - start) >> vm_kernel_page_shift;
-				advisory[advisories].size = (pgHi - pgLo) >> vm_kernel_page_shift;
-				advisories++;
-			}
-			break;
-		}
-		if (!msize) {
-#if DEBUG_MALLOC
-			malloc_report(ASL_LEVEL_ERR, "*** 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_kernel(current + sizeof(tiny_free_list_t) + sizeof(msize_t));
-			uintptr_t pgHi = trunc_page_kernel(current + TINY_BYTES_FOR_MSIZE(msize) - sizeof(msize_t));
-
-			if (pgLo < pgHi) {
-				advisory[advisories].pnum = (pgLo - start) >> vm_kernel_page_shift;
-				advisory[advisories].size = (pgHi - pgLo) >> vm_kernel_page_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(depot_ptr);
-		for (i = 0; i < advisories; ++i) {
-			uintptr_t addr = (advisory[i].pnum << vm_kernel_page_shift) + start;
-			size_t size = advisory[i].size << vm_kernel_page_shift;
-
-			mvm_madvise_free(rack, r, addr, addr + size, NULL, rack->debug_flags & MALLOC_DO_SCRIBBLE);
-		}
-		SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
-		OSAtomicDecrement32Barrier(&(REGION_TRAILER_FOR_TINY_REGION(r)->pinned_to_depot));
-	}
-}
-
-static region_t
-tiny_find_msize_region(rack_t *rack, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	tiny_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->p;
-	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->p;
-		if (ptr) {
-			return TINY_REGION_FOR_PTR(ptr);
-		} else {
-			/* Shouldn't happen. Fall through to look at last slot. */
-#if DEBUG_MALLOC
-			malloc_report(ASL_LEVEL_ERR, "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->p;
-	if (ptr) {
-		return TINY_REGION_FOR_PTR(ptr);
-	}
-
-	return NULL;
-}
-
-static MALLOC_INLINE void
-tiny_madvise_free_range_no_lock(rack_t *rack,
-								magazine_t *tiny_mag_ptr,
-								region_t region,
-								void *headptr,
-								size_t headsize,
-								void *ptr,
-								msize_t msize)
-{
-	region_trailer_t *node = REGION_TRAILER_FOR_TINY_REGION(region);
-
-	// Lock on tiny_magazines[mag_index] is already held here
-	// Calculate the first page in the coalesced block that would be safe to mark MADV_FREE
-	size_t free_header_size = sizeof(tiny_free_list_t) + sizeof(msize_t);
-	uintptr_t safe_ptr = (uintptr_t)ptr + free_header_size;
-	uintptr_t round_safe = round_page_kernel(safe_ptr);
-
-	// Calculate 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_kernel(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_kernel((uintptr_t)headptr - free_tail_size);
-		uintptr_t hi = round_page_kernel((uintptr_t)headptr + headsize + 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(rack, tiny_mag_ptr, ptr, msize);
-			set_tiny_meta_header_in_use(ptr, msize);
-
-			OSAtomicIncrement32Barrier(&(node->pinned_to_depot));
-			SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-			mvm_madvise_free(rack, region, free_lo, free_hi, &rack->last_madvise, rack->debug_flags & MALLOC_DO_SCRIBBLE);
-			SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-			OSAtomicDecrement32Barrier(&(node->pinned_to_depot));
-
-			set_tiny_meta_header_free(ptr, msize);
-			tiny_free_list_add_ptr(rack, tiny_mag_ptr, ptr, msize);
-		}
-	}
-}
-
-static boolean_t
-tiny_get_region_from_depot(rack_t *rack, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	magazine_t *depot_ptr = &(rack->magazines[DEPOT_MAGAZINE_INDEX]);
-
-	/* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
-	if (rack->num_magazines == 1) { // Uniprocessor, single magazine, so no recirculation necessary
-		return 0;
-	}
-
-#if DEBUG_MALLOC
-	if (DEPOT_MAGAZINE_INDEX == mag_index) {
-		malloc_zone_error(rack->debug_flags, true, "tiny_get_region_from_depot called for magazine index -1\n");
-		return 0;
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(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(rack, depot_ptr, DEPOT_MAGAZINE_INDEX, msize);
-		if (NULL == sparse_region) { // Depot empty?
-			SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
-			return 0;
-		}
-
-		node = REGION_TRAILER_FOR_TINY_REGION(sparse_region);
-		if (0 >= node->pinned_to_depot) {
-			break;
-		}
-
-		SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
-		yield();
-		SZONE_MAGAZINE_PTR_LOCK(depot_ptr);
-	}
-
-	// disconnect node from Depot
-	recirc_list_extract(rack, 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(rack, 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(rack, 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(rack, tiny_mag_ptr, node);
-
-	SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
-
-	// DTrace USDT Probe
-	MAGMALLOC_DEPOTREGION(TINY_SZONE_FROM_RACK(rack), (int)mag_index, (void *)sparse_region,
-			TINY_REGION_SIZE, (int)BYTES_USED_FOR_TINY_REGION(sparse_region));
-
-	return 1;
-}
-
-#if CONFIG_RECIRC_DEPOT
-static region_t
-tiny_free_try_depot_unmap_no_lock(rack_t *rack, magazine_t *depot_ptr, region_trailer_t *node)
-{
-	if (0 < node->bytes_used || 0 < node->pinned_to_depot ||
-		depot_ptr->recirculation_entries < recirc_retained_regions)
-	{
-		return NULL;
-	}
-
-	// disconnect node from Depot
-	recirc_list_extract(rack, 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(rack, 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(rack->region_generation->hashed_regions,
-				rack->region_generation->num_regions_allocated,
-				rack->region_generation->num_regions_allocated_shift,
-				sparse_region);
-
-		if (NULL == pSlot) {
-			malloc_zone_error(rack->debug_flags, true, "tiny_free_try_depot_unmap_no_lock hash lookup failed: %p\n", sparse_region);
-			return NULL;
-		}
-		*pSlot = HASHRING_REGION_DEALLOCATED;
-		depot_ptr->num_bytes_in_magazine -= TINY_REGION_PAYLOAD_BYTES;
-
-		// Atomically increment num_regions_dealloc
-#ifdef __LP64___
-		OSAtomicIncrement64(&rack->num_regions_dealloc);
-#else
-		OSAtomicIncrement32((int32_t *)&rack->num_regions_dealloc);
-#endif
-
-		// Caller will transfer ownership of the region back to the OS with no locks held
-		MAGMALLOC_DEALLOCREGION(TINY_SZONE_FROM_RACK(rack), (void *)sparse_region, TINY_REGION_SIZE); // DTrace USDT Probe
-		return sparse_region;
-	} else {
-		malloc_zone_error(rack->debug_flags, true, "tiny_free_try_depot_unmap_no_lock objects_in_use not zero: %d\n", objects_in_use);
-		return NULL;
-	}
-}
-
-static boolean_t
-tiny_free_do_recirc_to_depot(rack_t *rack, 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->pinned_to_depot)) {
-		// If we skip a node due to pinned_to_depot being non-zero, it must be
-		// because another thread is madvising the same region in
-		// tiny_madvise_free_range_no_lock(), called from tiny_free_no_lock().
-		// When that's done, the same thread will enter tiny_free_try_recirc_to_depot()
-		// for the same region, which will come back here. So this just defers
-		// recirculation of the region.
-		node = node->next;
-	}
-
-	if (NULL == node) {
-#if DEBUG_MALLOC
-		malloc_report(ASL_LEVEL_INFO, "*** tiny_free_do_recirc_to_depot end of list\n");
-#endif
-		return TRUE; // Caller must SZONE_MAGAZINE_PTR_UNLOCK(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(rack, tiny_mag_ptr);
-	}
-
-	// disconnect "suitable" node from magazine
-	recirc_list_extract(rack, 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(rack, tiny_mag_ptr, sparse_region);
-	magazine_t *depot_ptr = &(rack->magazines[DEPOT_MAGAZINE_INDEX]);
-
-	// hand over the region to the (locked) Depot
-	SZONE_MAGAZINE_PTR_LOCK(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(rack, 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(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(rack, depot_ptr, node);
-
-	MAGMALLOC_RECIRCREGION(TINY_SZONE_FROM_RACK(rack), (int)mag_index, (void *)sparse_region, TINY_REGION_SIZE,
-						   (int)BYTES_USED_FOR_TINY_REGION(sparse_region)); // DTrace USDT Probe
-
-#if !CONFIG_AGGRESSIVE_MADVISE
-	// Mark free'd dirty pages with MADV_FREE to reduce memory pressure
-	tiny_free_scan_madvise_free(rack, depot_ptr, sparse_region);
-#endif
-
-	// If the region is entirely empty vm_deallocate() it outside the depot lock
-	region_t r_dealloc = tiny_free_try_depot_unmap_no_lock(rack, depot_ptr, node);
-	SZONE_MAGAZINE_PTR_UNLOCK(depot_ptr);
-	if (r_dealloc) {
-		mvm_deallocate_pages(r_dealloc, TINY_REGION_SIZE, 0);
-	}
-	return FALSE; // Caller need not unlock the originating magazine
-}
-
-static MALLOC_INLINE boolean_t
-tiny_free_try_recirc_to_depot(rack_t *rack,
-							  magazine_t *tiny_mag_ptr,
-							  mag_index_t mag_index,
-							  region_t region,
-							  void *headptr,
-							  size_t headsize,
-							  void *ptr,
-							  msize_t msize)
-{
-	region_trailer_t *node = REGION_TRAILER_FOR_TINY_REGION(region);
-	size_t bytes_used = node->bytes_used;
-
-	/* FIXME: Would Uniprocessor benefit from recirc and MADV_FREE? */
-	if (rack->num_magazines == 1) { // Uniprocessor, single magazine, so no recirculation necessary
-		/* NOTHING */
-		return TRUE; // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr)
-	} 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(rack, tiny_mag_ptr, mag_index);
-		}
-	} else {
-#if !CONFIG_AGGRESSIVE_MADVISE
-		// We are free'ing into the depot, so madvise as we do so unless we were madvising every incoming
-		// allocation anyway.
-		tiny_madvise_free_range_no_lock(rack, tiny_mag_ptr, region, headptr, headsize, ptr, msize);
-#endif
-
-		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(rack, tiny_mag_ptr, node);
-			SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-			if (r_dealloc) {
-				mvm_deallocate_pages(r_dealloc, TINY_REGION_SIZE, 0);
-			}
-			return FALSE; // Caller need not unlock
-		}
-	}
-	return TRUE; // Caller must do SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr)
-}
-#endif // CONFIG_RECIRC_DEPOT
-
-boolean_t
-tiny_free_no_lock(rack_t *rack, 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;
-	tiny_free_list_t *big_free_block;
-	tiny_free_list_t *after_next_block;
-	tiny_free_list_t *before_next_block;
-
-#if DEBUG_MALLOC
-	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in tiny_free_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-	if (!msize) {
-		malloc_zone_error(rack->debug_flags, true,
-				"trying to free tiny block that is too small 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_report(ASL_LEVEL_INFO, "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(rack, 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_report(ASL_LEVEL_INFO, "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 = (tiny_free_list_t *)next_block;
-			after_next_block = free_list_unchecksum_ptr(rack, &big_free_block->next);
-			before_next_block = free_list_unchecksum_ptr(rack, &big_free_block->previous);
-
-			if (!before_next_block) {
-				tiny_mag_ptr->mag_free_list[NUM_TINY_SLOTS - 1].p = ptr;
-			} else {
-				before_next_block->next.u = free_list_checksum_ptr(rack, ptr);
-			}
-
-			if (after_next_block) {
-				after_next_block->previous.u = free_list_checksum_ptr(rack, ptr);
-			}
-
-			// we don't need to checksum these since they are already checksummed
-			((tiny_free_list_t *)ptr)->previous = big_free_block->previous;
-			((tiny_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(rack, 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 ((rack->debug_flags & MALLOC_DO_SCRIBBLE) && msize && (msize >= TINY_QUANTUM)) {
-		memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
-	}
-
-	tiny_free_list_add_ptr(rack, 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 = (unsigned int)bytes_used;
-
-#if CONFIG_AGGRESSIVE_MADVISE
-	// Platforms that want to madvise every freed allocation do so here, even if we continue
-	// on to use the recirc depot after.
-	tiny_madvise_free_range_no_lock(rack, tiny_mag_ptr, region, original_ptr, original_size, ptr, msize);
-#endif
-
-	// Caller must do SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr) if this function
-	// returns TRUE.
-	boolean_t needs_unlock = TRUE;
-
-#if CONFIG_RECIRC_DEPOT
-	needs_unlock = tiny_free_try_recirc_to_depot(rack, tiny_mag_ptr, mag_index, region, original_ptr, original_size, ptr, msize);
-#endif
-	return needs_unlock;
-}
-
-// Allocates from the last region or a freshly allocated region
-static void *
-tiny_malloc_from_region_no_lock(rack_t *rack,
-								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(rack, 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.
-#if NUM_TINY_BLOCKS & 31
-	const uint32_t header = 0xFFFFFFFFU << (NUM_TINY_BLOCKS & 31);
-#else
-	const uint32_t header = 0;
-#endif
-	((tiny_region_t)aligned_address)->pairs[CEIL_NUM_TINY_BLOCKS_WORDS - 1].header = header;
-	((tiny_region_t)aligned_address)->pairs[CEIL_NUM_TINY_BLOCKS_WORDS - 1].inuse = 0;
-
-	// 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
-	rack_region_insert(rack, (region_t)aligned_address);
-
-	tiny_mag_ptr->mag_last_region = aligned_address;
-	BYTES_USED_FOR_TINY_REGION(aligned_address) = TINY_BYTES_FOR_MSIZE(msize);
-
-#if CONFIG_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_report(ASL_LEVEL_INFO, "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 CONFIG_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(rack, tiny_mag_ptr, REGION_TRAILER_FOR_TINY_REGION(aligned_address));
-
-#if DEBUG_MALLOC
-	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in tiny_malloc_from_region_no_lock(), ptr=%p, msize=%d\n", ptr, msize);
-	}
-#endif
-	return ptr;
-}
-
-void *
-tiny_memalign(szone_t *szone, size_t alignment, size_t size, size_t span)
-{
-	msize_t mspan = TINY_MSIZE_FOR_BYTES(span + TINY_QUANTUM - 1);
-	void *p = tiny_malloc_should_clear(&szone->tiny_rack, 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->tiny_rack.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(tiny_mag_ptr);
-
-		// Give up mpad blocks beginning at p to the tiny free list
-		free_tiny(&szone->tiny_rack, p, TINY_REGION_FOR_PTR(p), TINY_BYTES_FOR_MSIZE(mpad));
-
-		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->tiny_rack.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(tiny_mag_ptr);
-
-		// Give up mwaste blocks beginning at q to the tiny free list
-		free_tiny(&szone->tiny_rack, q, TINY_REGION_FOR_PTR(q), TINY_BYTES_FOR_MSIZE(mwaste));
-	}
-
-	return p; // p has the desired size and alignment, and can later be free()'d
-}
-
-boolean_t
-tiny_claimed_address(rack_t *rack, void *ptr)
-{
-	region_t r = tiny_region_for_ptr_no_lock(rack, ptr);
-	return r && ptr < TINY_REGION_END(r);
-}
-
-void *
-tiny_try_shrink_in_place(rack_t *rack, 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(rack->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(tiny_mag_ptr);
-		free_tiny(rack, q, TINY_REGION_FOR_PTR(q), 0);
-	}
-	return ptr;
-}
-
-boolean_t
-tiny_try_realloc_in_place(rack_t *rack, 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, new_msize;
-	void *leftover;
-
-	index = TINY_INDEX_FOR_PTR(ptr);
-	old_msize = TINY_MSIZE_FOR_BYTES(old_size);
-	new_msize = TINY_MSIZE_FOR_BYTES(new_size + TINY_QUANTUM - 1);
-	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(rack->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(tiny_mag_ptr);
-		return 0;
-	}
-
-	coalesced_msize = new_msize - old_msize;
-#if CONFIG_TINY_CACHE
-	void *last_free_ptr = tiny_mag_ptr->mag_last_free;
-	msize_t last_free_msize = tiny_mag_ptr->mag_last_free_msize;
-	if (last_free_ptr == next_block && old_msize + last_free_msize >= new_msize) {
-		/*
-		 * There is a block in mag_last_free and it's immediately after
-		 * this block and it's large enough. We can use some or all of it.
-		 */
-		leftover_msize = last_free_msize - coalesced_msize;
-		if (leftover_msize) {
-			tiny_mag_ptr->mag_last_free_msize -= coalesced_msize;
-			tiny_mag_ptr->mag_last_free += new_size - old_size;
-			// The block in mag_last_free is still marked as header and in-use, so copy that
-			// state to the block that remains. The state for the block that we're going to
-			// use is adjusted by the set_tiny_meta_header_middle() call below.
-			set_tiny_meta_header_in_use(next_block + TINY_BYTES_FOR_MSIZE(coalesced_msize), leftover_msize);
-		} else {
-			// Using the whole block.
-			tiny_mag_ptr->mag_last_free = NULL;
-			tiny_mag_ptr->mag_last_free_msize = 0;
-			tiny_mag_ptr->mag_last_free_rgn = NULL;
-		}
-		set_tiny_meta_header_middle(next_block);
-	} else {
-#endif // CONFIG_TINY_CACHE
-		/*
-		 * Try to expand into unused space immediately after this block.
-		 */
-		msize_t unused_msize = TINY_MSIZE_FOR_BYTES(tiny_mag_ptr->mag_bytes_free_at_end);
-		void *unused_start = TINY_REGION_END(TINY_REGION_FOR_PTR(ptr)) - tiny_mag_ptr->mag_bytes_free_at_end;
-		if (tiny_mag_ptr->mag_last_region == TINY_REGION_FOR_PTR(ptr)
-				&& coalesced_msize < unused_msize && unused_start == ptr + old_size) {
-			// The block at the start of mag_bytes_free_at_end is marked as
-			// header/in-use and the next one has header/free. We need to
-			// reset both the header and in-use bit in the first block and we
-			// need to reset the header bit in the second block if it's part of
-			// the new allocation.
-			set_tiny_meta_header_middle(unused_start);
-			if (coalesced_msize > 1) {
-				set_tiny_meta_header_middle(unused_start + TINY_QUANTUM);
-			}
-			tiny_mag_ptr->mag_bytes_free_at_end -= TINY_BYTES_FOR_MSIZE(coalesced_msize);
-			if (tiny_mag_ptr->mag_bytes_free_at_end) {
-				// Mark the first block of the remaining free area as a header and in-use.
-				set_tiny_meta_header_in_use_1(ptr + TINY_BYTES_FOR_MSIZE(new_msize));
-			}
-		} else {
-			/*
-			 * 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(tiny_mag_ptr);
-				return 0; // next_block is in use;
-			}
-			next_msize = get_tiny_free_size(next_block);
-			if (old_msize + next_msize < new_msize) {
-				SZONE_MAGAZINE_PTR_UNLOCK(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(rack, tiny_mag_ptr, next_block, next_msize);
-			set_tiny_meta_header_middle(next_block); // clear the meta_header to enable coalescing backwards
-			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(rack, tiny_mag_ptr, leftover, leftover_msize);
-			}
-			set_tiny_meta_header_in_use(ptr, old_msize + coalesced_msize);
-		}
-#if CONFIG_TINY_CACHE
-	}
-#endif // CONFIG_TINY_CACHE
-#if DEBUG_MALLOC
-	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "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 = (unsigned int)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(tiny_mag_ptr);
-	CHECK(szone, __PRETTY_FUNCTION__);
-	return 1;
-}
-
-static char *tiny_check_fail_msg = "*** check: incorrect tiny region ";
-
-#define TINY_CHECK_FAIL(fmt, ...) \
-	malloc_zone_check_fail(tiny_check_fail_msg, \
-			"%ld, counter=%d\n" fmt, region_index, counter, __VA_ARGS__);
-
-boolean_t
-tiny_check_region(rack_t *rack, region_t region, size_t region_index,
-		unsigned counter)
-{
-	uintptr_t start, ptr, region_end;
-	boolean_t prev_free = 0;
-	boolean_t is_free;
-	msize_t msize;
-	tiny_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 = &(rack->magazines[mag_index]);
-
-	// Assumes locked
-	CHECK_MAGAZINE_PTR_LOCKED(szone, tiny_mag_ptr, __PRETTY_FUNCTION__);
-
-	// Do not check the region if pinned_to_depot is not zero because it
-	// may not be in a consistent state (specifically, if may have a
-	// block marked as in-use that's longer than any legal allocation,
-	// which upsets get_tiny_meta_header() because it can't determine the
-	// block's length).
-	if (!REGION_TRAILER_FOR_TINY_REGION(region)->pinned_to_depot) {
-		return 1;
-	}
-
-	/* 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)) {
-				TINY_CHECK_FAIL("*** invariant broken for leader block %p - %d %d\n",
-						(void *)(ptr - TINY_QUANTUM), msize, is_free);
-				return 0;
-			}
-		}
-	}
-	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) {
-			TINY_CHECK_FAIL("*** invariant broken for tiny block %p this msize=%d - size is too small\n", (void *)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)) {
-				TINY_CHECK_FAIL("*** invariant broken for %p this tiny msize=%d - size is too large\n", (void *)ptr, msize);
-				return 0;
-			}
-			/* move to next block */
-			ptr += TINY_BYTES_FOR_MSIZE(msize);
-		} else {
-#if !CONFIG_RELAXED_INVARIANT_CHECKS
-			/*
-			 * Free blocks must have been coalesced, we cannot have a free block following another
-			 * free block.
-			 */
-			if (prev_free) {
-				TINY_CHECK_FAIL("*** invariant broken for free block %p this tiny msize=%d: two free blocks in a row\n", (void *)ptr, msize);
-				return 0;
-			}
-#endif // CONFIG_RELAXED_INVARIANT_CHECKS
-			prev_free = 1;
-			/*
-			 * Check the integrity of this block's entry in its freelist.
-			 */
-			free_head = (tiny_free_list_t *)ptr;
-			previous = free_list_unchecksum_ptr(rack, &free_head->previous);
-			next = free_list_unchecksum_ptr(rack, &free_head->next);
-			if (previous && !tiny_meta_header_is_free(previous)) {
-				TINY_CHECK_FAIL("*** invariant broken for %p (previous %p is not a free pointer)\n", (void *)ptr, previous);
-				return 0;
-			}
-			if (next && !tiny_meta_header_is_free(next)) {
-				TINY_CHECK_FAIL("*** invariant broken for %p (next in free list %p is not a free pointer)\n", (void *)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)) {
-				TINY_CHECK_FAIL("*** invariant broken for tiny free %p followed by %p in region [%p-%p] "
-						"(end marker incorrect) should be %d; in fact %d\n",
-						(void *)ptr, follower, TINY_REGION_ADDRESS(region), (void *)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) {
-		TINY_CHECK_FAIL("*** invariant broken for region end %p - %p\n", (void *)ptr, (void *)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)) {
-				TINY_CHECK_FAIL("*** invariant broken for blocker block %p - %d %d\n", (void *)ptr, msize, is_free);
-				return 0;
-			}
-		}
-	}
-	return 1;
-}
-
-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_rack.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_rack.magazines), szone->tiny_rack.num_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) {
-				vm_address_t mag_last_free;
-				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 = (uintptr_t)tiny_mag_ptr->mag_last_free;
-					mag_last_free_msize = tiny_mag_ptr->mag_last_free_msize;
-				} else {
-					for (mag_index = 0; mag_index < szone->tiny_rack.num_magazines; mag_index++) {
-						if ((void *)range.address == (tiny_mag_base + mag_index)->mag_last_free_rgn) {
-							mag_last_free = (uintptr_t)(tiny_mag_base + mag_index)->mag_last_free;
-							mag_last_free_msize = (tiny_mag_base + mag_index)->mag_last_free_msize;
-						}
-					}
-				}
-
-				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) {
-						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;
-}
-
-void *
-tiny_malloc_from_free_list(rack_t *rack, magazine_t *tiny_mag_ptr, mag_index_t mag_index, msize_t msize)
-{
-	tiny_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;
-	tiny_free_list_t *next;
-	free_list_t *limit;
-#if defined(__LP64__)
-	uint64_t bitmap;
-#else
-	uint32_t bitmap;
-#endif
-	msize_t leftover_msize;
-	tiny_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->p;
-	if (ptr) {
-		next = free_list_unchecksum_ptr(rack, &ptr->next);
-		if (next) {
-			next->previous = ptr->previous;
-		} else {
-			BITMAPV_CLR(tiny_mag_ptr->mag_bitmap, slot);
-		}
-		the_slot->p = next;
-		this_msize = msize;
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr)) {
-			malloc_report(ASL_LEVEL_INFO, "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->p;
-		if (ptr) {
-			next = free_list_unchecksum_ptr(rack, &ptr->next);
-			free_list->p = 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_report(ASL_LEVEL_ERR, "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->p;
-	if (ptr) {
-		this_msize = get_tiny_free_size(ptr);
-		next = free_list_unchecksum_ptr(rack, &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 = (tiny_free_list_t *)((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
-			limit->p = leftover_ptr;
-			if (next) {
-				next->previous.u = free_list_checksum_ptr(rack, 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_report(ASL_LEVEL_INFO,
-							  "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->p = 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 = (tiny_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_report(ASL_LEVEL_INFO, "in tiny_malloc_from_free_list(), from end ptr=%p, msize=%d\n", ptr, msize);
-		}
-#endif
-		goto return_tiny_alloc;
-	}
-#if CONFIG_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 = (tiny_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_report(ASL_LEVEL_INFO, "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 = (tiny_free_list_t *)((unsigned char *)ptr + TINY_BYTES_FOR_MSIZE(msize));
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr)) {
-			malloc_report(ASL_LEVEL_INFO, "in tiny_malloc_from_free_list(), adding leftover ptr=%p, this_msize=%d\n", ptr, this_msize);
-		}
-#endif
-		tiny_free_list_add_ptr(rack, 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 = (unsigned int)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_report(ASL_LEVEL_INFO, "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;
-}
-
-void *
-tiny_malloc_should_clear(rack_t *rack, msize_t msize, boolean_t cleared_requested)
-{
-	void *ptr;
-	mag_index_t mag_index = tiny_mag_get_thread_index() % rack->num_magazines;
-	magazine_t *tiny_mag_ptr = &(rack->magazines[mag_index]);
-
-	MALLOC_TRACE(TRACE_tiny_malloc, (uintptr_t)rack, TINY_BYTES_FOR_MSIZE(msize), (uintptr_t)tiny_mag_ptr, cleared_requested);
-
-#if DEBUG_MALLOC
-	if (DEPOT_MAGAZINE_INDEX == mag_index) {
-		malloc_zone_error(rack->debug_flags, true, "malloc called for magazine index -1\n");
-		return (NULL);
-	}
-
-	if (!msize) {
-		malloc_zone_error(rack->debug_flags, true, "invariant broken (!msize) in allocation (region)\n");
-		return (NULL);
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-
-#if CONFIG_TINY_CACHE
-	ptr = tiny_mag_ptr->mag_last_free;
-
-	if (tiny_mag_ptr->mag_last_free_msize == msize) {
-		// we have a winner
-		tiny_mag_ptr->mag_last_free = NULL;
-		tiny_mag_ptr->mag_last_free_msize = 0;
-		tiny_mag_ptr->mag_last_free_rgn = NULL;
-		SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-		CHECK(szone, __PRETTY_FUNCTION__);
-		if (cleared_requested) {
-			memset(ptr, 0, TINY_BYTES_FOR_MSIZE(msize));
-		}
-#if DEBUG_MALLOC
-		if (LOG(szone, ptr)) {
-			malloc_report(ASL_LEVEL_INFO, "in tiny_malloc_should_clear(), tiny cache ptr=%p, msize=%d\n", ptr, msize);
-		}
-#endif
-		return ptr;
-	}
-#endif /* CONFIG_TINY_CACHE */
-
-	while (1) {
-		ptr = tiny_malloc_from_free_list(rack, tiny_mag_ptr, mag_index, msize);
-		if (ptr) {
-			SZONE_MAGAZINE_PTR_UNLOCK(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(rack, tiny_mag_ptr, mag_index, msize)) {
-			ptr = tiny_malloc_from_free_list(rack, tiny_mag_ptr, mag_index, msize);
-			if (ptr) {
-				SZONE_MAGAZINE_PTR_UNLOCK(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(tiny_mag_ptr);
-			fresh_region = mvm_allocate_pages_securely(TINY_REGION_SIZE, TINY_BLOCKS_ALIGN, VM_MEMORY_MALLOC_TINY, rack->debug_flags);
-			SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-
-			// DTrace USDT Probe
-			MAGMALLOC_ALLOCREGION(TINY_SZONE_FROM_RACK(rack), (int)mag_index, fresh_region, TINY_REGION_SIZE);
-
-			if (!fresh_region) { // out of memory!
-				tiny_mag_ptr->alloc_underway = FALSE;
-				OSMemoryBarrier();
-				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-				return NULL;
-			}
-
-			ptr = tiny_malloc_from_region_no_lock(rack, 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(tiny_mag_ptr);
-			CHECK(szone, __PRETTY_FUNCTION__);
-			return ptr;
-		} else {
-			SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-			yield();
-			SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-		}
-	}
-	/* NOTREACHED */
-}
-
-size_t
-tiny_size(rack_t *rack, const void *ptr)
-{
-	if (tiny_region_for_ptr_no_lock(rack, ptr)) {
-		if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS) {
-			return 0;
-		}
-
-		boolean_t is_free;
-		msize_t msize = get_tiny_meta_header(ptr, &is_free);
-		if (is_free) {
-			return 0;
-		}
-
-#if CONFIG_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 = &rack->magazines[mag_index];
-
-				if (msize < TINY_QUANTUM && ptr == tiny_mag_ptr->mag_last_free) {
-					return 0;
-				}
-			} else {
-				for (mag_index = 0; mag_index < rack->num_magazines; mag_index++) {
-					magazine_t *tiny_mag_ptr = &(rack->magazines[mag_index]);
-
-					if (msize < TINY_QUANTUM && ptr == tiny_mag_ptr->mag_last_free) {
-						return 0;
-					}
-				}
-			}
-		}
-#endif
-		return TINY_BYTES_FOR_MSIZE(msize);
-	}
-
-	return 0;
-}
-
-static MALLOC_NOINLINE void
-free_tiny_botch(rack_t *rack, tiny_free_list_t *ptr)
-{
-	mag_index_t mag_index = MAGAZINE_INDEX_FOR_TINY_REGION(TINY_REGION_FOR_PTR(ptr));
-	magazine_t *tiny_mag_ptr = &(rack->magazines[mag_index]);
-	SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-	malloc_zone_error(rack->debug_flags, true, "Double free of object %p\n", ptr);
-}
-
-void
-free_tiny(rack_t *rack, 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 = &(rack->magazines[mag_index]);
-
-	MALLOC_TRACE(TRACE_tiny_free, (uintptr_t)rack, (uintptr_t)ptr, (uintptr_t)tiny_mag_ptr, known_size);
-
-	// 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(rack, ptr);
-			return;
-		}
-	}
-#if DEBUG_MALLOC
-	if (!msize) {
-		malloc_report(ASL_LEVEL_ERR, "*** free_tiny() block in use is too large: %p\n", ptr);
-		return;
-	}
-#endif
-
-	SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-
-#if CONFIG_TINY_CACHE
-	// Depot does not participate in CONFIG_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
-			msize_t msize2 = tiny_mag_ptr->mag_last_free_msize;
-			region_t rgn2 = tiny_mag_ptr->mag_last_free_rgn;
-
-			/* check that we don't already have this pointer in the cache */
-			if (ptr == ptr2) {
-				free_tiny_botch(rack, ptr);
-				return;
-			}
-
-			if ((rack->debug_flags & MALLOC_DO_SCRIBBLE) && msize) {
-				memset(ptr, SCRABBLE_BYTE, TINY_BYTES_FOR_MSIZE(msize));
-			}
-
-			tiny_mag_ptr->mag_last_free = ptr;
-			tiny_mag_ptr->mag_last_free_msize = msize;
-			tiny_mag_ptr->mag_last_free_rgn = tiny_region;
-
-			if (!ptr2) {
-				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-				CHECK(szone, __PRETTY_FUNCTION__);
-				return;
-			}
-
-			msize = msize2;
-			ptr = ptr2;
-			tiny_region = rgn2;
-		}
-	}
-#endif /* CONFIG_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(tiny_mag_ptr);
-		mag_index = refreshed_index;
-		tiny_mag_ptr = &(rack->magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-	}
-
-	if (tiny_free_no_lock(rack, tiny_mag_ptr, mag_index, tiny_region, ptr, msize)) {
-		SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-	}
-
-	CHECK(szone, __PRETTY_FUNCTION__);
-}
-
-unsigned
-tiny_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 = tiny_mag_get_thread_index() % szone->tiny_rack.num_magazines;
-	magazine_t *tiny_mag_ptr = &(szone->tiny_rack.magazines[mag_index]);
-
-	// 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(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_rack, tiny_mag_ptr, mag_index, msize);
-		if (!ptr) {
-			break;
-		}
-
-		*results++ = ptr;
-		found++;
-	}
-	SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-	return found;
-}
-
-void
-tiny_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;
-	}
-
-	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(tiny_mag_ptr);
-					tiny_mag_ptr = NULL;
-				}
-
-				tiny_region = tiny_region_for_ptr_no_lock(&szone->tiny_rack, ptr);
-
-				if (tiny_region) {
-					tiny_mag_ptr = mag_lock_zine_for_region_trailer(szone->tiny_rack.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_rack, 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(tiny_mag_ptr);
-		tiny_mag_ptr = NULL;
-	}
-}
-
-
-void
-print_tiny_free_list(rack_t *rack)
-{
-	tiny_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 < rack->num_magazines; mag_index++) {
-			grain_t slot = 0;
-			_simple_sprintf(b, "\tMagazine %d: ", mag_index);
-			while (slot < NUM_TINY_SLOTS) {
-				ptr = rack->magazines[mag_index].mag_free_list[slot].p;
-				if (ptr) {
-					_simple_sprintf(b, "%s%y[%d]; ", (slot == NUM_TINY_SLOTS - 1) ? ">=" : "", (slot + 1) * TINY_QUANTUM,
-									free_list_count(rack, (free_list_t){ .p = ptr }));
-				}
-				slot++;
-			}
-			_simple_sappend(b, "\n");
-		}
-		malloc_report(MALLOC_REPORT_NOLOG | MALLOC_REPORT_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-
-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_start;
-	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_report(MALLOC_REPORT_NOLOG | MALLOC_REPORT_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(tiny_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_report(ASL_LEVEL_ERR, "*** error with %p: msize=%d\n", (void *)current, (unsigned)msize);
-			break;
-		}
-		if (!is_free) {
-			// block in use
-			if (msize > NUM_TINY_SLOTS) {
-				malloc_report(ASL_LEVEL_ERR, "*** 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(tiny_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_report(MALLOC_REPORT_NOLOG | MALLOC_REPORT_NOPREFIX, "%s\n", _simple_string(b));
-		_simple_sfree(b);
-	}
-}
-
-static char *tiny_freelist_fail_msg = "check: tiny free list incorrect ";
-
-#define TINY_FREELIST_FAIL(fmt, ...) \
-	malloc_zone_check_fail(tiny_freelist_fail_msg, \
-			" (slot=%u), counter=%d\n" fmt, slot, counter, __VA_ARGS__);
-
-boolean_t
-tiny_free_list_check(rack_t *rack, grain_t slot, unsigned counter)
-{
-	mag_index_t mag_index;
-
-	for (mag_index = -1; mag_index < rack->num_magazines; mag_index++) {
-		magazine_t *tiny_mag_ptr = &(rack->magazines[mag_index]);
-		SZONE_MAGAZINE_PTR_LOCK(tiny_mag_ptr);
-
-		unsigned count = 0;
-		tiny_free_list_t *ptr = rack->magazines[mag_index].mag_free_list[slot].p;
-		boolean_t is_free;
-		tiny_free_list_t *previous = NULL;
-
-		while (ptr) {
-			is_free = tiny_meta_header_is_free(ptr);
-			if (!is_free) {
-				TINY_FREELIST_FAIL("*** in-use ptr in free list slot=%u count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-				return 0;
-			}
-			if (((uintptr_t)ptr) & (TINY_QUANTUM - 1)) {
-				TINY_FREELIST_FAIL("*** unaligned ptr in free list slot=%u count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-				return 0;
-			}
-			if (!tiny_region_for_ptr_no_lock(rack, ptr)) {
-				TINY_FREELIST_FAIL("*** ptr not in szone slot=%d  count=%u ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-				return 0;
-			}
-			if (free_list_unchecksum_ptr(rack, &ptr->previous) != previous) {
-				TINY_FREELIST_FAIL("*** previous incorrectly set slot=%u count=%d ptr=%p\n", slot, count, ptr);
-				SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-				return 0;
-			}
-			previous = ptr;
-			ptr = free_list_unchecksum_ptr(rack, &ptr->next);
-			count++;
-		}
-		
-		SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
-	}
-	return 1;
-}