--- libmalloc/libmalloc-317.40.8/src/magazine_malloc.c
+++ libmalloc/libmalloc-116.50.8/src/magazine_malloc.c
@@ -26,16 +26,25 @@
 /*
  * 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
+ * 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.
  */
 
 #include "internal.h"
+
+static volatile uintptr_t entropic_address = 0;
+static volatile uintptr_t entropic_limit = 0;
+#define ENTROPIC_KABILLION 0x10000000 /* 256Mb */
+
+// <rdar://problem/22277891> align 64bit ARM shift to 32MB PTE entries
+#if MALLOC_TARGET_IOS && MALLOC_TARGET_64BIT
+#define ENTROPIC_SHIFT 25
+#else // MALLOC_TARGET_IOS && MALLOC_TARGET_64BIT
+#define ENTROPIC_SHIFT SMALL_BLOCKS_ALIGN
+#endif
 
 #if DEBUG_MALLOC
 #define LOG(szone, ptr) (szone->log_address && (((uintptr_t)szone->log_address == -1) || (szone->log_address == (void *)(ptr))))
@@ -43,36 +52,298 @@
 #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
+/*********************	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, ...
+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 & MALLOC_ABORT_ON_CORRUPTION)) ||
+			(szone->debug_flags & MALLOC_ABORT_ON_ERROR)) {
+		_os_set_crash_log_message_dynamic(b ? _simple_string(b) : msg);
+		abort();
+	} else if (b) {
+		_simple_sfree(b);
+	}
+}
+
+void
+protect(void *address, size_t size, unsigned protection, unsigned debug_flags)
+{
+	kern_return_t err;
+
+	if (!(debug_flags & 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 & 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);
+		}
+	}
+}
+
+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 & MALLOC_ADD_GUARD_PAGES;
+	boolean_t purgeable = debug_flags & 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)", (void *)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)", (void *)(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;
+}
+
+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;
+}
+
+void
+deallocate_pages(szone_t *szone, void *addr, size_t size, unsigned debug_flags)
+{
+	boolean_t add_guard_pages = debug_flags & 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);
+	}
+}
+
+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 & 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, (int)len); // DTrace USDT Probe
+		if (-1 == madvise((void *)pgLo, len, CONFIG_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;
+}
+
+int
+madvise_reuse_range(szone_t *szone, region_t r, uintptr_t pgLo, uintptr_t phHi)
+{
+	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;
+		}
+	}
+	return 0;
+}
 
 /*********************	Zone call backs	************************/
 /*
@@ -86,7 +357,7 @@
 
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in szone_free with %p\n", ptr);
+		malloc_printf("in szone_free with %p\n", ptr);
 	}
 #endif
 	if (!ptr) {
@@ -96,15 +367,15 @@
 	 * Try to free to a tiny region.
 	 */
 	if ((uintptr_t)ptr & (TINY_QUANTUM - 1)) {
-		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed\n", ptr);
+		szone_error(szone, 1, "Non-aligned pointer being freed", ptr, NULL);
 		return;
 	}
-	if ((tiny_region = tiny_region_for_ptr_no_lock(&szone->tiny_rack, ptr)) != NULL) {
+	if ((tiny_region = tiny_region_for_ptr_no_lock(szone, ptr)) != NULL) {
 		if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS) {
-			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed\n", ptr);
+			szone_error(szone, 1, "Pointer to metadata being freed", ptr, NULL);
 			return;
 		}
-		free_tiny(&szone->tiny_rack, ptr, tiny_region, 0, false);
+		free_tiny(szone, ptr, tiny_region, 0);
 		return;
 	}
 
@@ -112,35 +383,21 @@
 	 * Try to free to a small region.
 	 */
 	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1)) {
-		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed (2)\n", ptr);
+		szone_error(szone, 1, "Non-aligned pointer being freed (2)", ptr, NULL);
 		return;
 	}
-	if ((small_region = small_region_for_ptr_no_lock(&szone->small_rack, ptr)) != NULL) {
+	if ((small_region = small_region_for_ptr_no_lock(szone, ptr)) != NULL) {
 		if (SMALL_META_INDEX_FOR_PTR(ptr) >= NUM_SMALL_BLOCKS) {
-			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed (2)\n", ptr);
+			szone_error(szone, 1, "Pointer to metadata being freed (2)", ptr, NULL);
 			return;
 		}
-		free_small(&szone->small_rack, ptr, small_region, 0);
+		free_small(szone, 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)) {
-		malloc_zone_error(szone->debug_flags, true, "non-page-aligned, non-allocated pointer %p being freed\n", ptr);
+		szone_error(szone, 1, "non-page-aligned, non-allocated pointer being freed", ptr, NULL);
 		return;
 	}
 	free_large(szone, ptr);
@@ -151,11 +408,11 @@
 {
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in szone_free_definite_size with %p\n", ptr);
+		malloc_printf("in szone_free_definite_size with %p\n", ptr);
 	}
 
 	if (0 == size) {
-		malloc_zone_error(szone->debug_flags, true, "pointer %p of size zero being freed\n", ptr);
+		szone_error(szone, 1, "pointer of size zero being freed", ptr, NULL);
 		return;
 	}
 
@@ -168,15 +425,15 @@
 	 * Try to free to a tiny region.
 	 */
 	if ((uintptr_t)ptr & (TINY_QUANTUM - 1)) {
-		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed\n", ptr);
+		szone_error(szone, 1, "Non-aligned pointer being freed", ptr, NULL);
 		return;
 	}
-	if (size <= TINY_LIMIT_THRESHOLD) {
+	if (size <= SMALL_THRESHOLD) {
 		if (TINY_INDEX_FOR_PTR(ptr) >= NUM_TINY_BLOCKS) {
-			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed\n", ptr);
+			szone_error(szone, 1, "Pointer to metadata being freed", ptr, NULL);
 			return;
 		}
-		free_tiny(&szone->tiny_rack, ptr, TINY_REGION_FOR_PTR(ptr), size, false);
+		free_tiny(szone, ptr, TINY_REGION_FOR_PTR(ptr), size);
 		return;
 	}
 
@@ -184,35 +441,21 @@
 	 * Try to free to a small region.
 	 */
 	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1)) {
-		malloc_zone_error(szone->debug_flags, true, "Non-aligned pointer %p being freed (2)\n", ptr);
+		szone_error(szone, 1, "Non-aligned pointer being freed (2)", ptr, NULL);
 		return;
 	}
-	if (size <= SMALL_LIMIT_THRESHOLD) {
+	if (size <= szone->large_threshold) {
 		if (SMALL_META_INDEX_FOR_PTR(ptr) >= NUM_SMALL_BLOCKS) {
-			malloc_zone_error(szone->debug_flags, true, "Pointer %p to metadata being freed (2)\n", ptr);
+			szone_error(szone, 1, "Pointer to metadata being freed (2)", ptr, NULL);
 			return;
 		}
-		free_small(&szone->small_rack, ptr, SMALL_REGION_FOR_PTR(ptr), size);
+		free_small(szone, 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)) {
-		malloc_zone_error(szone->debug_flags, true, "non-page-aligned, non-allocated pointer %p being freed\n", ptr);
+		szone_error(szone, 1, "non-page-aligned, non-allocated pointer being freed", ptr, NULL);
 		return;
 	}
 	free_large(szone, ptr);
@@ -224,28 +467,25 @@
 	void *ptr;
 	msize_t msize;
 
-	if (size <= TINY_LIMIT_THRESHOLD) {
+	if (size <= SMALL_THRESHOLD) {
+		// tiny size: <1024 bytes (64-bit), <512 bytes (32-bit)
+		// think tiny
 		msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
 		if (!msize) {
 			msize = 1;
 		}
-		ptr = tiny_malloc_should_clear(&szone->tiny_rack, msize, cleared_requested);
-	} else if (size <= SMALL_LIMIT_THRESHOLD) {
+		ptr = tiny_malloc_should_clear(szone, msize, cleared_requested);
+	} else if (size <= szone->large_threshold) {
+		// small size: <15k (<1GB machines), <127k (>1GB machines)
+		// think small
 		msize = SMALL_MSIZE_FOR_BYTES(size + SMALL_QUANTUM - 1);
 		if (!msize) {
 			msize = 1;
 		}
-		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
+		ptr = small_malloc_should_clear(szone, msize, cleared_requested);
 	} else {
-		size_t num_kernel_pages = round_large_page_quanta(size) >> large_vm_page_quanta_shift;
+		// large: all other allocations
+		size_t num_kernel_pages = round_page_quanta(size) >> vm_page_quanta_shift;
 		if (num_kernel_pages == 0) { /* Overflowed */
 			ptr = 0;
 		} else {
@@ -254,7 +494,7 @@
 	}
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "szone_malloc returned %p\n", ptr);
+		malloc_printf("szone_malloc returned %p\n", ptr);
 	}
 #endif
 	/*
@@ -276,10 +516,29 @@
 void *
 szone_calloc(szone_t *szone, size_t num_items, size_t size)
 {
-	size_t total_bytes;
-	if (calloc_get_size(num_items, size, 0, &total_bytes)) {
-		return NULL;
-	}
+	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
+	}
+
 	return szone_malloc_should_clear(szone, total_bytes, 1);
 }
 
@@ -288,18 +547,18 @@
 {
 	void *ptr;
 
-	if (size <= MEDIUM_LIMIT_THRESHOLD) {
+	if (size <= szone->large_threshold) {
 		ptr = szone_memalign(szone, vm_page_quanta_size, size);
 	} else {
 		size_t num_kernel_pages;
 
-		num_kernel_pages = round_large_page_quanta(size) >> large_vm_page_quanta_shift;
+		num_kernel_pages = round_page_quanta(size) >> vm_page_quanta_shift;
 		ptr = large_malloc(szone, num_kernel_pages, 0, 0);
 	}
 
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "szone_valloc returned %p\n", ptr);
+		malloc_printf("szone_valloc returned %p\n", ptr);
 	}
 #endif
 	return ptr;
@@ -320,7 +579,7 @@
 	SZONE_UNLOCK(szone);
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "szone_size for %p returned %d\n", ptr, (unsigned)size);
+		malloc_printf("szone_size for %p returned %d\n", ptr, (unsigned)size);
 	}
 #endif
 	return size;
@@ -329,14 +588,15 @@
 size_t
 szone_size(szone_t *szone, const void *ptr)
 {
-	size_t sz = 0;
+	boolean_t is_free;
+	msize_t msize, msize_and_free;
 
 	if (!ptr) {
 		return 0;
 	}
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in szone_size for %p (szone=%p)\n", ptr, szone);
+		malloc_printf("in szone_size for %p (szone=%p)\n", ptr, szone);
 	}
 #endif
 
@@ -346,10 +606,35 @@
 	if ((uintptr_t)ptr & (TINY_QUANTUM - 1)) {
 		return 0;
 	}
-
-	sz = tiny_size(&szone->tiny_rack, ptr);
-	if (sz) {
-		return sz;
+	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 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 = &(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);
 	}
 
 	/*
@@ -358,23 +643,36 @@
 	if ((uintptr_t)ptr & (SMALL_QUANTUM - 1)) {
 		return 0;
 	}
-
-	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 (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 CONFIG_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);
+	}
 
 	/*
 	 * If not page-aligned, it cannot have come from a large allocation.
@@ -397,7 +695,7 @@
 
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "in szone_realloc for %p, %d\n", ptr, (unsigned)new_size);
+		malloc_printf("in szone_realloc for %p, %d\n", ptr, (unsigned)new_size);
 	}
 #endif
 	if (NULL == ptr) {
@@ -413,7 +711,7 @@
 
 	old_size = szone_size(szone, ptr);
 	if (!old_size) {
-		malloc_zone_error(szone->debug_flags, true, "pointer %p being reallocated was not allocated\n", ptr);
+		szone_error(szone, 1, "pointer being reallocated was not allocated", ptr, NULL);
 		return NULL;
 	}
 
@@ -426,13 +724,13 @@
 	 * 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 <= TINY_LIMIT_THRESHOLD) {
-		if (old_size <= TINY_LIMIT_THRESHOLD) {
+	if (new_good_size <= SMALL_THRESHOLD) {
+		if (old_size <= SMALL_THRESHOLD) {
 			if (new_good_size <= (old_size >> 1)) {
 				/*
 				 * Serious shrinkage (more than half). free() the excess.
 				 */
-				return tiny_try_shrink_in_place(&szone->tiny_rack, ptr, old_size, new_good_size);
+				return tiny_try_shrink_in_place(szone, 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).
@@ -442,7 +740,7 @@
 					memset(ptr + new_size, SCRIBBLE_BYTE, old_size - new_size);
 				}
 				return ptr;
-			} else if (tiny_try_realloc_in_place(&szone->tiny_rack, ptr, old_size, new_good_size)) { // try to grow the allocation
+			} else if (tiny_try_realloc_in_place(szone, 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);
 				}
@@ -455,46 +753,27 @@
 		 * belongs to a small region, and we're not protecting the small allocations
 		 * try to reallocate in-place.
 		 */
-	} else if (new_good_size <= SMALL_LIMIT_THRESHOLD) {
-		if (TINY_LIMIT_THRESHOLD < old_size && old_size <= SMALL_LIMIT_THRESHOLD) {
+	} else if (new_good_size <= szone->large_threshold) {
+		if (SMALL_THRESHOLD < old_size && old_size <= szone->large_threshold) {
 			if (new_good_size <= (old_size >> 1)) {
-				return small_try_shrink_in_place(&szone->small_rack, ptr, old_size, new_good_size);
+				return small_try_shrink_in_place(szone, 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);
 				}
 				return ptr;
-			} else if (small_try_realloc_in_place(&szone->small_rack, ptr, old_size, new_good_size)) {
+			} else if (small_try_realloc_in_place(szone, 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 & MALLOC_PURGEABLE) && // purgeable needs fresh allocation
-			   (old_size > LARGE_THRESHOLD(szone)) && (new_good_size > LARGE_THRESHOLD(szone))) {
+			   (old_size > szone->large_threshold) && (new_good_size > szone->large_threshold)) {
 		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) {
@@ -532,18 +811,15 @@
 	 * if it's too small, just copy by hand.
 	 */
 	valid_size = MIN(old_size, new_size);
-#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
-	{
+	if ((valid_size < szone->vm_copy_threshold) ||
+			vm_copy(mach_task_self(), (vm_address_t)ptr, valid_size, (vm_address_t)new_ptr)) {
 		memcpy(new_ptr, ptr, valid_size);
 	}
 	szone_free(szone, ptr);
 
 #if DEBUG_MALLOC
 	if (LOG(szone, ptr)) {
-		malloc_report(ASL_LEVEL_INFO, "szone_realloc returned %p for %d\n", new_ptr, (unsigned)new_size);
+		malloc_printf("szone_realloc returned %p for %d\n", new_ptr, (unsigned)new_size);
 	}
 #endif
 	return new_ptr;
@@ -559,79 +835,98 @@
 		return NULL;
 	}
 
-	// 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
+	// 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
 	size_t span = size + alignment - 1;
 
 	if (alignment <= TINY_QUANTUM) {
-		// Trivially satisfied by tiny, small, medium, or large.
-		return szone_malloc(szone, size);
-	}
-	if (span <= TINY_LIMIT_THRESHOLD) {
+		return szone_malloc(szone, size); // Trivially satisfied by tiny, small, or large
+
+	} else if (span <= SMALL_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) {
+
+	} else if (SMALL_THRESHOLD < size && alignment <= SMALL_QUANTUM) {
+		return szone_malloc(szone, size); // Trivially satisfied by small or large
+
+	} else if (span <= szone->large_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;
-		}
-		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 if (szone->large_threshold < size && alignment <= vm_page_quanta_size) {
+		return szone_malloc(szone, size); // Trivially satisfied by large
+
 	} else {
-		return large_malloc(szone, num_kernel_pages,
-				MAX(vm_page_quanta_shift, __builtin_ctz((unsigned)alignment)), 0);
+		// 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((unsigned)alignment)), 0);
+		}
+
+		return p;
 	}
 	/* NOTREACHED */
-	__builtin_unreachable();
-}
-
-// Given a size, returns the number of pointers allocated capable of holding
+}
+
+// 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.
 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 <= TINY_LIMIT_THRESHOLD) {
-		return tiny_batch_malloc(szone, size, results, count);
-	}
-	return 0;
-}
-
+	if (size > SMALL_THRESHOLD) {
+		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. */
 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) {
@@ -639,14 +934,54 @@
 	}
 
 	CHECK(szone, __PRETTY_FUNCTION__);
-
-	// 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);
+	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;
+	}
 
 	CHECK(szone, __PRETTY_FUNCTION__);
 	while (count--) {
-		void *ptr = to_be_freed[count];
+		ptr = to_be_freed[count];
 		if (ptr) {
 			szone_free(szone, ptr);
 		}
@@ -662,36 +997,34 @@
 	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);
-		}
+	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);
 	}
 #endif
 
@@ -701,30 +1034,44 @@
 		large = szone->large_entries + index;
 		if (large->address) {
 			// we deallocate_pages, including guard pages
-			mvm_deallocate_pages((void *)(large->address), large->size, szone->debug_flags);
+			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) {
-		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);
+		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, MALLOC_ADD_GUARD_PAGES);
+	deallocate_pages(szone, (void *)&(szone->small_magazines[-1]), SMALL_MAGAZINE_PAGED_SIZE, MALLOC_ADD_GUARD_PAGES);
+	deallocate_pages(szone, (void *)szone, SZONE_PAGED_SIZE, 0);
 }
 
 size_t
@@ -733,7 +1080,7 @@
 	msize_t msize;
 
 	// Find a good size for this tiny allocation.
-	if (size <= TINY_LIMIT_THRESHOLD) {
+	if (size <= SMALL_THRESHOLD) {
 		msize = TINY_MSIZE_FOR_BYTES(size + TINY_QUANTUM - 1);
 		if (!msize) {
 			msize = 1;
@@ -742,7 +1089,7 @@
 	}
 
 	// Find a good size for this small allocation.
-	if (size <= SMALL_LIMIT_THRESHOLD) {
+	if (size <= szone->large_threshold) {
 		msize = SMALL_MSIZE_FOR_BYTES(size + SMALL_QUANTUM - 1);
 		if (!msize) {
 			msize = 1;
@@ -750,19 +1097,9 @@
 		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_large_page_quanta(size)) {
+	if (size > round_page_quanta(size)) {
 		return (size_t)(-1LL);
 	}
 
@@ -771,22 +1108,10 @@
 	// 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_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);
+		malloc_printf("szone_good_size() invariant broken %y\n", size);
+	}
+#endif
+	return round_page_quanta(size);
 }
 
 unsigned szone_check_counter = 0;
@@ -799,95 +1124,70 @@
 	size_t index;
 
 	/* check tiny regions - chould check region count */
-	for (index = 0; index < szone->tiny_rack.region_generation->num_regions_allocated; ++index) {
-		region_t tiny = szone->tiny_rack.region_generation->hashed_regions[index];
+	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) {
 			continue;
 		}
 
 		if (tiny) {
-			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);
+			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);
 				return 0;
 			}
-			SZONE_MAGAZINE_PTR_UNLOCK(tiny_mag_ptr);
+			SZONE_MAGAZINE_PTR_UNLOCK(szone, tiny_mag_ptr);
 		}
 	}
 	/* check tiny free lists */
 	for (index = 0; index < NUM_TINY_SLOTS; ++index) {
-		if (!tiny_free_list_check(&szone->tiny_rack, (grain_t)index, szone_check_counter)) {
+		if (!tiny_free_list_check(szone, (grain_t)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);
 			return 0;
 		}
 	}
 
 	/* check small regions - could check region count */
-	for (index = 0; index < szone->small_rack.region_generation->num_regions_allocated; ++index) {
-		region_t small = szone->small_rack.region_generation->hashed_regions[index];
+	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) {
 			continue;
 		}
 
 		if (small) {
-			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);
+			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);
 				return 0;
 			}
-			SZONE_MAGAZINE_PTR_UNLOCK(small_mag_ptr);
+			SZONE_MAGAZINE_PTR_UNLOCK(szone, small_mag_ptr);
 		}
 	}
 	/* check small free lists */
-	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)) {
+	for (index = 0; index < szone->num_small_slots; ++index) {
+		if (!small_free_list_check(szone, (grain_t)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);
 			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;
 }
@@ -896,7 +1196,7 @@
 szone_check(szone_t *szone)
 {
 	if ((++szone_check_counter % 10000) == 0) {
-		malloc_report(ASL_LEVEL_NOTICE, "at szone_check counter=%d\n", szone_check_counter);
+		_malloc_printf(ASL_LEVEL_NOTICE, "at szone_check counter=%d\n", szone_check_counter);
 	}
 
 	if (szone_check_counter < szone_check_start) {
@@ -922,7 +1222,7 @@
 	kern_return_t err;
 
 	if (!reader) {
-		reader = _malloc_default_reader;
+		reader = _szone_default_reader;
 	}
 
 	err = reader(task, zone_address, sizeof(szone_t), (void **)&szone);
@@ -940,23 +1240,14 @@
 		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;
 }
 
-static boolean_t
-scalable_zone_info_task(task_t task, memory_reader_t reader,
-		malloc_zone_t *zone, unsigned *info_to_fill, unsigned count)
+// 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];
@@ -968,30 +1259,21 @@
 	size_t u = 0;
 	mag_index_t mag_index;
 
-	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;
+	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] = (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;
+	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] = (unsigned)t;
@@ -1008,271 +1290,69 @@
 	info[0] = info[4] + info[6] + info[8] + info[10];
 	info[1] = info[5] + info[7] + info[9] + info[11];
 
-	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[3] = (unsigned)(szone->num_tiny_regions - szone->num_tiny_regions_dealloc) * TINY_REGION_SIZE +
+			  (unsigned)(szone->num_small_regions - szone->num_small_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 MALLOC_NOINLINE void
-szone_print(task_t task, unsigned level, vm_address_t zone_address,
-		memory_reader_t reader, print_task_printer_t printer)
+szone_print(szone_t *szone, boolean_t verbose)
 {
 	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]);
+
+	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]);
 	// tiny
-	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];
+	_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];
 		if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
-			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);
-	}
-
+			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);
+	}
 	// small
-	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];
+	_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];
 		if (HASHRING_OPEN_ENTRY != region && HASHRING_REGION_DEALLOCATED != region) {
-			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
+			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 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);
+		}
+	}
+	if (verbose) {
+		print_small_free_list(szone);
+	}
 }
 
 static void
@@ -1289,12 +1369,12 @@
 szone_force_lock_magazine(szone_t *szone, magazine_t *mag)
 {
 	while (1) {
-		SZONE_MAGAZINE_PTR_LOCK(mag);
+		SZONE_MAGAZINE_PTR_LOCK(szone, mag);
 		if (!mag->alloc_underway) {
 			return;
 		}
 
-		SZONE_MAGAZINE_PTR_UNLOCK(mag);
+		SZONE_MAGAZINE_PTR_UNLOCK(szone, mag);
 		yield();
 	}
 }
@@ -1304,24 +1384,15 @@
 {
 	mag_index_t i;
 
-	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
+	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]);
 
 	SZONE_LOCK(szone);
 }
@@ -1333,20 +1404,12 @@
 
 	SZONE_UNLOCK(szone);
 
-#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])));
+	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])));
 	}
 }
 
@@ -1357,20 +1420,12 @@
 
 	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])));
+	for (i = -1; i < szone->num_small_magazines; ++i) {
+		SZONE_MAGAZINE_PTR_REINIT_LOCK(szone, (&(szone->small_magazines[i])));
+	}
+
+	for (i = -1; i < szone->num_tiny_magazines; ++i) {
+		SZONE_MAGAZINE_PTR_REINIT_LOCK(szone, (&(szone->tiny_magazines[i])));
 	}
 }
 
@@ -1386,32 +1441,20 @@
 	}
 	SZONE_UNLOCK(szone);
 
-#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])));
+	for (i = -1; i < szone->num_small_magazines; ++i) {
+		tookLock = SZONE_MAGAZINE_PTR_TRY_LOCK(szone, (&(szone->small_magazines[i])));
 		if (tookLock == 0) {
 			return 1;
 		}
-		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])));
+		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) {
 			return 1;
 		}
-		SZONE_MAGAZINE_PTR_UNLOCK((&(szone->tiny_rack.magazines[i])));
+		SZONE_MAGAZINE_PTR_UNLOCK(szone, (&(szone->tiny_magazines[i])));
 	}
 	return 0;
 }
@@ -1421,27 +1464,166 @@
 {
 	size_t total = 0;
 
-	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
+	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 CONFIG_LARGE_CACHE
-	if (large_cache_enabled && szone->flotsam_enabled) {
+	if (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_HIGH];
+		large_entry_t local_entry_cache[LARGE_ENTRY_CACHE_SIZE];
 
 		memcpy((void *)local_entry_cache, (void *)szone->large_entry_cache, sizeof(local_entry_cache));
 
@@ -1458,22 +1640,20 @@
 		// deallocate the death-row cache outside the zone lock
 		size_t total = 0;
 		while (idx != idx_max) {
-			mvm_deallocate_pages((void *)local_entry_cache[idx].address, local_entry_cache[idx].size, szone->debug_flags);
+			deallocate_pages(szone, (void *)local_entry_cache[idx].address, local_entry_cache[idx].size, 0);
 			total += local_entry_cache[idx].size;
-			if (++idx == szone->large_cache_depth) {
+			if (++idx == LARGE_ENTRY_CACHE_SIZE) {
 				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);
+			deallocate_pages(szone, (void *)local_entry_cache[idx].address, local_entry_cache[idx].size, 0);
 			total += local_entry_cache[idx].size;
 		}
 	}
 #endif
 
-	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);
-
+	MAGMALLOC_PRESSURERELIEF((void *)szone, (int)goal, (int)total); // DTrace USDT Probe
 	return total;
 }
 
@@ -1489,16 +1669,16 @@
 		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;
+		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;
 		}
 
 		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->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;
 	}
@@ -1508,16 +1688,16 @@
 		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;
+		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->small_rack.num_regions - szone->small_rack.num_regions_dealloc) * SMALL_REGION_SIZE;
+		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;
 	}
@@ -1531,118 +1711,50 @@
 		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;
-			}
-		}
-
-		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;
-
+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;
 
-	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;
+	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->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
+			(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;
-
-	return KERN_SUCCESS;
-}
-
-static void
-szone_statistics(szone_t *szone, malloc_statistics_t *stats)
-{
-	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_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. */
-		(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
+		(void *)szone_reinit_lock, // reinit_lock version 9 and foward
 }; // marked as const to spare the DATA section
 
 szone_t *
@@ -1652,12 +1764,12 @@
 
 #if defined(__i386__) || defined(__x86_64__)
 	if (_COMM_PAGE_VERSION_REQD > (*((uint16_t *)_COMM_PAGE_VERSION))) {
-		MALLOC_REPORT_FATAL_ERROR((*((uint16_t *)_COMM_PAGE_VERSION)), "comm page version mismatch");
+		MALLOC_PRINTF_FATAL_ERROR((*((uint16_t *)_COMM_PAGE_VERSION)), "comm page version mismatch");
 	}
 #endif
 
 	/* get memory for the zone. */
-	szone = mvm_allocate_pages(SZONE_PAGED_SIZE, 0, DISABLE_ASLR, VM_MEMORY_MALLOC);
+	szone = allocate_pages(NULL, SZONE_PAGED_SIZE, 0, 0, VM_MEMORY_MALLOC);
 	if (!szone) {
 		return NULL;
 	}
@@ -1671,67 +1783,99 @@
 #warning LOG enabled
 	szone->log_address = ~0;
 #endif
-
-	if (mvm_aslr_enabled()) {
+	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;
+
+#if CONFIG_SMALL_CUTTOFF_127KB 
+	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 // CONFIG_SMALL_CUTTOFF_127KB
+	szone->is_largemem = 0;
+	szone->num_small_slots = NUM_SMALL_SLOTS;
+	szone->large_threshold = LARGE_THRESHOLD;
+	szone->vm_copy_threshold = VM_COPY_THRESHOLD;
+#endif // CONFIG_SMALL_CUTTOFF_127KB
+
+#if CONFIG_LARGE_CACHE
+	uint64_t hw_memsize = 0;
+
+#if CONFIG_HAS_COMMPAGE_MEMSIZE
+	hw_memsize = *(uint64_t *)(uintptr_t)_COMM_PAGE_MEMORY_SIZE;
+#else
+	size_t uint64_t_size = sizeof(hw_memsize);
+	// hw_memsize was always 0 if sysctlbyname failed, so preserve that behaviour
+	(void)sysctlbyname("hw.memsize", &hw_memsize, &uint64_t_size, 0, 0);
+#endif
+
+	// madvise(..., MADV_REUSABLE) death-row arrivals above this threshold [~0.1%]
+	szone->large_entry_cache_reserve_limit = hw_memsize >> 10; 
+
+	/* <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)) << ENTROPIC_SHIFT);
+			(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
+		}
 		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;
 	}
 
-#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;
-		}
-	}
+#else
+	malloc_entropy[0] = 0;
+	malloc_entropy[1] = 0;
+	debug_flags |= DISABLE_ASLR;
 #endif
 
 	// Initialize the security token.
 	szone->cookie = (uintptr_t)malloc_entropy[0];
 
-	szone->basic_zone.version = 12;
+	szone->basic_zone.version = 9;
 	szone->basic_zone.size = (void *)szone_size;
 	szone->basic_zone.malloc = (void *)szone_malloc;
 	szone->basic_zone.calloc = (void *)szone_calloc;
@@ -1745,20 +1889,95 @@
 	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.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->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;
 	_malloc_lock_init(&szone->large_szone_lock);
 
 	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, 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(i, "magazine mask exceeds allocated magazines");
+	}
+
+	// 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, 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(i, "magazine mask exceeds allocated magazines");
+	}
+
+	// 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 szone;