memory/jemalloc/jemalloc.c
author Matt Brubeck <mbrubeck@mozilla.com>
Thu, 05 May 2011 14:21:38 -0700
changeset 69030 eaaa24ff93a01a285fda5bcfbef01c6cad99e69b
parent 68658 1e64d699aa012c88e45473b97ce43c70f91f5046
child 69100 9253e72c98ad5d45920918e357b7f44c77b52af9
permissions -rw-r--r--
Back out changeset 1defe29fdf3c, ffe31dc2d27f, 54bacc404a6f, 16772cb4a781, c169c3b8dfb2, 94f06945b818, 6a2724d755f3 for test failure.

/* -*- Mode: C; tab-width: 8; c-basic-offset: 8; indent-tabs-mode: t -*- */
/* vim:set softtabstop=8 shiftwidth=8: */
/*-
 * Copyright (C) 2006-2008 Jason Evans <jasone@FreeBSD.org>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice(s), this list of conditions and the following disclaimer as
 *    the first lines of this file unmodified other than the possible
 *    addition of one or more copyright notices.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice(s), this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *******************************************************************************
 *
 * This allocator implementation is designed to provide scalable performance
 * for multi-threaded programs on multi-processor systems.  The following
 * features are included for this purpose:
 *
 *   + Multiple arenas are used if there are multiple CPUs, which reduces lock
 *     contention and cache sloshing.
 *
 *   + Cache line sharing between arenas is avoided for internal data
 *     structures.
 *
 *   + Memory is managed in chunks and runs (chunks can be split into runs),
 *     rather than as individual pages.  This provides a constant-time
 *     mechanism for associating allocations with particular arenas.
 *
 * Allocation requests are rounded up to the nearest size class, and no record
 * of the original request size is maintained.  Allocations are broken into
 * categories according to size class.  Assuming runtime defaults, 4 kB pages
 * and a 16 byte quantum on a 32-bit system, the size classes in each category
 * are as follows:
 *
 *   |=====================================|
 *   | Category | Subcategory    |    Size |
 *   |=====================================|
 *   | Small    | Tiny           |       2 |
 *   |          |                |       4 |
 *   |          |                |       8 |
 *   |          |----------------+---------|
 *   |          | Quantum-spaced |      16 |
 *   |          |                |      32 |
 *   |          |                |      48 |
 *   |          |                |     ... |
 *   |          |                |     480 |
 *   |          |                |     496 |
 *   |          |                |     512 |
 *   |          |----------------+---------|
 *   |          | Sub-page       |    1 kB |
 *   |          |                |    2 kB |
 *   |=====================================|
 *   | Large                     |    4 kB |
 *   |                           |    8 kB |
 *   |                           |   12 kB |
 *   |                           |     ... |
 *   |                           | 1012 kB |
 *   |                           | 1016 kB |
 *   |                           | 1020 kB |
 *   |=====================================|
 *   | Huge                      |    1 MB |
 *   |                           |    2 MB |
 *   |                           |    3 MB |
 *   |                           |     ... |
 *   |=====================================|
 *
 * A different mechanism is used for each category:
 *
 *   Small : Each size class is segregated into its own set of runs.  Each run
 *           maintains a bitmap of which regions are free/allocated.
 *
 *   Large : Each allocation is backed by a dedicated run.  Metadata are stored
 *           in the associated arena chunk header maps.
 *
 *   Huge : Each allocation is backed by a dedicated contiguous set of chunks.
 *          Metadata are stored in a separate red-black tree.
 *
 *******************************************************************************
 */

#ifdef MOZ_MEMORY_ANDROID
#define NO_TLS
#define _pthread_self() pthread_self()
#endif

/*
 * MALLOC_PRODUCTION disables assertions and statistics gathering.  It also
 * defaults the A and J runtime options to off.  These settings are appropriate
 * for production systems.
 */
#ifndef MOZ_MEMORY_DEBUG
#  define	MALLOC_PRODUCTION
#endif

/*
 * Use only one arena by default.  Mozilla does not currently make extensive
 * use of concurrent allocation, so the increased fragmentation associated with
 * multiple arenas is not warranted.
 */
#define	MOZ_MEMORY_NARENAS_DEFAULT_ONE

/*
 * MALLOC_STATS enables statistics calculation, and is required for
 * jemalloc_stats().
 */
#define MALLOC_STATS

#ifndef MALLOC_PRODUCTION
   /*
    * MALLOC_DEBUG enables assertions and other sanity checks, and disables
    * inline functions.
    */
#  define MALLOC_DEBUG

   /* Memory filling (junk/zero). */
#  define MALLOC_FILL

   /* Allocation tracing. */
#  ifndef MOZ_MEMORY_WINDOWS
#    define MALLOC_UTRACE
#  endif

   /* Support optional abort() on OOM. */
#  define MALLOC_XMALLOC

   /* Support SYSV semantics. */
#  define MALLOC_SYSV
#endif

/*
 * MALLOC_VALIDATE causes malloc_usable_size() to perform some pointer
 * validation.  There are many possible errors that validation does not even
 * attempt to detect.
 */
#define MALLOC_VALIDATE

/* Embed no-op macros that support memory allocation tracking via valgrind. */
#ifdef MOZ_VALGRIND
#  define MALLOC_VALGRIND
#endif
#ifdef MALLOC_VALGRIND
#  include <valgrind/valgrind.h>
#else
#  define VALGRIND_MALLOCLIKE_BLOCK(addr, sizeB, rzB, is_zeroed)
#  define VALGRIND_FREELIKE_BLOCK(addr, rzB)
#endif

/*
 * MALLOC_BALANCE enables monitoring of arena lock contention and dynamically
 * re-balances arena load if exponentially averaged contention exceeds a
 * certain threshold.
 */
/* #define	MALLOC_BALANCE */

#if (!defined(MOZ_MEMORY_WINDOWS) && !defined(MOZ_MEMORY_DARWIN))
   /*
    * MALLOC_PAGEFILE causes all mmap()ed memory to be backed by temporary
    * files, so that if a chunk is mapped, it is guaranteed to be swappable.
    * This avoids asynchronous OOM failures that are due to VM over-commit.
    *
    * XXX OS X over-commits, so we should probably use mmap() instead of
    * vm_allocate(), so that MALLOC_PAGEFILE works.
    */
#define MALLOC_PAGEFILE
#endif

#ifdef MALLOC_PAGEFILE
/* Write size when initializing a page file. */
#  define MALLOC_PAGEFILE_WRITE_SIZE 512
#endif

#if defined(MOZ_MEMORY_LINUX) && !defined(MOZ_MEMORY_ANDROID)
#define	_GNU_SOURCE /* For mremap(2). */
#define	issetugid() 0
#if 0 /* Enable in order to test decommit code on Linux. */
#  define MALLOC_DECOMMIT
#endif
#endif

#ifndef MOZ_MEMORY_WINCE
#include <sys/types.h>

#include <errno.h>
#include <stdlib.h>
#endif
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#ifdef MOZ_MEMORY_WINDOWS
#ifndef MOZ_MEMORY_WINCE
#include <cruntime.h>
#include <internal.h>
#include <io.h>
#else
#include <cmnintrin.h>
#include <crtdefs.h>
#define SIZE_MAX UINT_MAX
#endif
#include <windows.h>

#pragma warning( disable: 4267 4996 4146 )

#define	bool BOOL
#define	false FALSE
#define	true TRUE
#define	inline __inline
#define	SIZE_T_MAX SIZE_MAX
#define	STDERR_FILENO 2
#define	PATH_MAX MAX_PATH
#define	vsnprintf _vsnprintf

#ifndef NO_TLS
static unsigned long tlsIndex = 0xffffffff;
#endif 

#define	__thread
#ifdef MOZ_MEMORY_WINCE
#define	_pthread_self() GetCurrentThreadId()
#else
#define	_pthread_self() __threadid()
#endif
#define	issetugid() 0

#ifndef MOZ_MEMORY_WINCE
/* use MSVC intrinsics */
#pragma intrinsic(_BitScanForward)
static __forceinline int
ffs(int x)
{
	unsigned long i;

	if (_BitScanForward(&i, x) != 0)
		return (i + 1);

	return (0);
}

/* Implement getenv without using malloc */
static char mozillaMallocOptionsBuf[64];

#define	getenv xgetenv
static char *
getenv(const char *name)
{

	if (GetEnvironmentVariableA(name, (LPSTR)&mozillaMallocOptionsBuf,
		    sizeof(mozillaMallocOptionsBuf)) > 0)
		return (mozillaMallocOptionsBuf);

	return (NULL);
}

#else /* WIN CE */

#define ENOMEM          12
#define EINVAL          22

static __forceinline int
ffs(int x)
{

	return 32 - _CountLeadingZeros((-x) & x);
}
#endif

typedef unsigned char uint8_t;
typedef unsigned uint32_t;
typedef unsigned long long uint64_t;
typedef unsigned long long uintmax_t;
#if defined(MOZ_MEMORY_SIZEOF_PTR_2POW) && (MOZ_MEMORY_SIZEOF_PTR_2POW == 3)
typedef long long ssize_t;
#else
typedef long ssize_t;
#endif

#define	MALLOC_DECOMMIT
#endif

#ifndef MOZ_MEMORY_WINDOWS
#ifndef MOZ_MEMORY_SOLARIS
#include <sys/cdefs.h>
#endif
#ifndef __DECONST
#  define __DECONST(type, var)	((type)(uintptr_t)(const void *)(var))
#endif
#ifndef MOZ_MEMORY
__FBSDID("$FreeBSD: head/lib/libc/stdlib/malloc.c 180599 2008-07-18 19:35:44Z jasone $");
#include "libc_private.h"
#ifdef MALLOC_DEBUG
#  define _LOCK_DEBUG
#endif
#include "spinlock.h"
#include "namespace.h"
#endif
#include <sys/mman.h>
#ifndef MADV_FREE
#  define MADV_FREE	MADV_DONTNEED
#endif
#ifndef MAP_NOSYNC
#  define MAP_NOSYNC	0
#endif
#include <sys/param.h>
#ifndef MOZ_MEMORY
#include <sys/stddef.h>
#endif
#include <sys/time.h>
#include <sys/types.h>
#if !defined(MOZ_MEMORY_SOLARIS) && !defined(MOZ_MEMORY_ANDROID)
#include <sys/sysctl.h>
#endif
#include <sys/uio.h>
#ifndef MOZ_MEMORY
#include <sys/ktrace.h> /* Must come after several other sys/ includes. */

#include <machine/atomic.h>
#include <machine/cpufunc.h>
#include <machine/vmparam.h>
#endif

#include <errno.h>
#include <limits.h>
#ifndef SIZE_T_MAX
#  define SIZE_T_MAX	SIZE_MAX
#endif
#include <pthread.h>
#ifdef MOZ_MEMORY_DARWIN
#define _pthread_self pthread_self
#define _pthread_mutex_init pthread_mutex_init
#define _pthread_mutex_trylock pthread_mutex_trylock
#define _pthread_mutex_lock pthread_mutex_lock
#define _pthread_mutex_unlock pthread_mutex_unlock
#endif
#include <sched.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#ifndef MOZ_MEMORY_DARWIN
#include <strings.h>
#endif
#include <unistd.h>

#ifdef MOZ_MEMORY_DARWIN
#include <libkern/OSAtomic.h>
#include <mach/mach_error.h>
#include <mach/mach_init.h>
#include <mach/vm_map.h>
#include <malloc/malloc.h>
#endif

#ifndef MOZ_MEMORY
#include "un-namespace.h"
#endif

#endif

#include "jemalloc.h"

/* Some tools, such as /dev/dsp wrappers, LD_PRELOAD libraries that
 * happen to override mmap() and call dlsym() from their overridden
 * mmap(). The problem is that dlsym() calls malloc(), and this ends
 * up in a dead lock in jemalloc.
 * On these systems, we prefer to directly use the system call.
 * We do that for Linux systems and kfreebsd with GNU userland.
 * Note sanity checks are not done (alignment of offset, ...) because
 * the uses of mmap are pretty limited, in jemalloc.
 *
 * On Alpha, glibc has a bug that prevents syscall() to work for system
 * calls with 6 arguments
 */
#if (defined(MOZ_MEMORY_LINUX) && !defined(__alpha__)) || \
    (defined(MOZ_MEMORY_BSD) && defined(__GLIBC__))
#include <sys/syscall.h>
#if defined(SYS_mmap) || defined(SYS_mmap2)
static inline
void *_mmap(void *addr, size_t length, int prot, int flags,
            int fd, off_t offset)
{
/* S390 only passes one argument to the mmap system call, which is a
 * pointer to a structure containing the arguments */
#ifdef __s390__
	struct {
		void *addr;
		size_t length;
		int prot;
		int flags;
		int fd;
		off_t offset;
	} args = { addr, length, prot, flags, fd, offset };
	return (void *) syscall(SYS_mmap, &args);
#else
#ifdef SYS_mmap2
	return (void *) syscall(SYS_mmap2, addr, length, prot, flags,
	                       fd, offset >> 12);
#else
	return (void *) syscall(SYS_mmap, addr, length, prot, flags,
                               fd, offset);
#endif
#endif
}
#define mmap _mmap
#define munmap(a, l) syscall(SYS_munmap, a, l)
#endif
#endif

#ifdef MOZ_MEMORY_DARWIN
static const bool __isthreaded = true;
#endif

#if defined(MOZ_MEMORY_SOLARIS) && defined(MAP_ALIGN) && !defined(JEMALLOC_NEVER_USES_MAP_ALIGN)
#define JEMALLOC_USES_MAP_ALIGN	 /* Required on Solaris 10. Might improve performance elsewhere. */
#endif

#if defined(MOZ_MEMORY_WINCE) && !defined(MOZ_MEMORY_WINCE6)
#define JEMALLOC_USES_MAP_ALIGN	 /* Required for Windows CE < 6 */
#endif

#define __DECONST(type, var) ((type)(uintptr_t)(const void *)(var))

#ifdef MOZ_MEMORY_WINDOWS
   /* MSVC++ does not support C99 variable-length arrays. */
#  define RB_NO_C99_VARARRAYS
#endif
#include "rb.h"

#ifdef MALLOC_DEBUG
   /* Disable inlining to make debugging easier. */
#ifdef inline
#undef inline
#endif

#  define inline
#endif

/* Size of stack-allocated buffer passed to strerror_r(). */
#define	STRERROR_BUF		64

/* Minimum alignment of allocations is 2^QUANTUM_2POW_MIN bytes. */
#  define QUANTUM_2POW_MIN      4
#ifdef MOZ_MEMORY_SIZEOF_PTR_2POW
#  define SIZEOF_PTR_2POW		MOZ_MEMORY_SIZEOF_PTR_2POW
#else
#  define SIZEOF_PTR_2POW       2
#endif
#define PIC
#ifndef MOZ_MEMORY_DARWIN
static const bool __isthreaded = true;
#else
#  define NO_TLS
#endif
#if 0
#ifdef __i386__
#  define QUANTUM_2POW_MIN	4
#  define SIZEOF_PTR_2POW	2
#  define CPU_SPINWAIT		__asm__ volatile("pause")
#endif
#ifdef __ia64__
#  define QUANTUM_2POW_MIN	4
#  define SIZEOF_PTR_2POW	3
#endif
#ifdef __alpha__
#  define QUANTUM_2POW_MIN	4
#  define SIZEOF_PTR_2POW	3
#  define NO_TLS
#endif
#ifdef __sparc64__
#  define QUANTUM_2POW_MIN	4
#  define SIZEOF_PTR_2POW	3
#  define NO_TLS
#endif
#ifdef __amd64__
#  define QUANTUM_2POW_MIN	4
#  define SIZEOF_PTR_2POW	3
#  define CPU_SPINWAIT		__asm__ volatile("pause")
#endif
#ifdef __arm__
#  define QUANTUM_2POW_MIN	3
#  define SIZEOF_PTR_2POW	2
#  define NO_TLS
#endif
#ifdef __mips__
#  define QUANTUM_2POW_MIN	3
#  define SIZEOF_PTR_2POW	2
#  define NO_TLS
#endif
#ifdef __powerpc__
#  define QUANTUM_2POW_MIN	4
#  define SIZEOF_PTR_2POW	2
#endif
#endif

#define	SIZEOF_PTR		(1U << SIZEOF_PTR_2POW)

/* sizeof(int) == (1U << SIZEOF_INT_2POW). */
#ifndef SIZEOF_INT_2POW
#  define SIZEOF_INT_2POW	2
#endif

/* We can't use TLS in non-PIC programs, since TLS relies on loader magic. */
#if (!defined(PIC) && !defined(NO_TLS))
#  define NO_TLS
#endif

#ifdef NO_TLS
   /* MALLOC_BALANCE requires TLS. */
#  ifdef MALLOC_BALANCE
#    undef MALLOC_BALANCE
#  endif
#endif

/*
 * Size and alignment of memory chunks that are allocated by the OS's virtual
 * memory system.
 */
#if defined(MOZ_MEMORY_WINCE) && !defined(MOZ_MEMORY_WINCE6)
#define	CHUNK_2POW_DEFAULT	21
#else
#define	CHUNK_2POW_DEFAULT	20
#endif
/* Maximum number of dirty pages per arena. */
#define	DIRTY_MAX_DEFAULT	(1U << 10)

/*
 * Maximum size of L1 cache line.  This is used to avoid cache line aliasing,
 * so over-estimates are okay (up to a point), but under-estimates will
 * negatively affect performance.
 */
#define	CACHELINE_2POW		6
#define	CACHELINE		((size_t)(1U << CACHELINE_2POW))

/* Smallest size class to support. */
#define	TINY_MIN_2POW		1

/*
 * Maximum size class that is a multiple of the quantum, but not (necessarily)
 * a power of 2.  Above this size, allocations are rounded up to the nearest
 * power of 2.
 */
#define	SMALL_MAX_2POW_DEFAULT	9
#define	SMALL_MAX_DEFAULT	(1U << SMALL_MAX_2POW_DEFAULT)

/*
 * RUN_MAX_OVRHD indicates maximum desired run header overhead.  Runs are sized
 * as small as possible such that this setting is still honored, without
 * violating other constraints.  The goal is to make runs as small as possible
 * without exceeding a per run external fragmentation threshold.
 *
 * We use binary fixed point math for overhead computations, where the binary
 * point is implicitly RUN_BFP bits to the left.
 *
 * Note that it is possible to set RUN_MAX_OVRHD low enough that it cannot be
 * honored for some/all object sizes, since there is one bit of header overhead
 * per object (plus a constant).  This constraint is relaxed (ignored) for runs
 * that are so small that the per-region overhead is greater than:
 *
 *   (RUN_MAX_OVRHD / (reg_size << (3+RUN_BFP))
 */
#define	RUN_BFP			12
/*                                    \/   Implicit binary fixed point. */
#define	RUN_MAX_OVRHD		0x0000003dU
#define	RUN_MAX_OVRHD_RELAX	0x00001800U

/* Put a cap on small object run size.  This overrides RUN_MAX_OVRHD. */
#define	RUN_MAX_SMALL_2POW	15
#define	RUN_MAX_SMALL		(1U << RUN_MAX_SMALL_2POW)

/*
 * Hyper-threaded CPUs may need a special instruction inside spin loops in
 * order to yield to another virtual CPU.  If no such instruction is defined
 * above, make CPU_SPINWAIT a no-op.
 */
#ifndef CPU_SPINWAIT
#  define CPU_SPINWAIT
#endif

/*
 * Adaptive spinning must eventually switch to blocking, in order to avoid the
 * potential for priority inversion deadlock.  Backing off past a certain point
 * can actually waste time.
 */
#define	SPIN_LIMIT_2POW		11

/*
 * Conversion from spinning to blocking is expensive; we use (1U <<
 * BLOCK_COST_2POW) to estimate how many more times costly blocking is than
 * worst-case spinning.
 */
#define	BLOCK_COST_2POW		4

#ifdef MALLOC_BALANCE
   /*
    * We use an exponential moving average to track recent lock contention,
    * where the size of the history window is N, and alpha=2/(N+1).
    *
    * Due to integer math rounding, very small values here can cause
    * substantial degradation in accuracy, thus making the moving average decay
    * faster than it would with precise calculation.
    */
#  define BALANCE_ALPHA_INV_2POW	9

   /*
    * Threshold value for the exponential moving contention average at which to
    * re-assign a thread.
    */
#  define BALANCE_THRESHOLD_DEFAULT	(1U << (SPIN_LIMIT_2POW-4))
#endif

/******************************************************************************/

/*
 * Mutexes based on spinlocks.  We can't use normal pthread spinlocks in all
 * places, because they require malloc()ed memory, which causes bootstrapping
 * issues in some cases.
 */
#if defined(MOZ_MEMORY_WINDOWS)
#define malloc_mutex_t CRITICAL_SECTION
#define malloc_spinlock_t CRITICAL_SECTION
#elif defined(MOZ_MEMORY_DARWIN)
typedef struct {
	OSSpinLock	lock;
} malloc_mutex_t;
typedef struct {
	OSSpinLock	lock;
} malloc_spinlock_t;
#elif defined(MOZ_MEMORY)
typedef pthread_mutex_t malloc_mutex_t;
typedef pthread_mutex_t malloc_spinlock_t;
#else
/* XXX these should #ifdef these for freebsd (and linux?) only */
typedef struct {
	spinlock_t	lock;
} malloc_mutex_t;
typedef malloc_spinlock_t malloc_mutex_t;
#endif

/* Set to true once the allocator has been initialized. */
static bool malloc_initialized = false;

#if defined(MOZ_MEMORY_WINDOWS)
/* No init lock for Windows. */
#elif defined(MOZ_MEMORY_DARWIN)
static malloc_mutex_t init_lock = {OS_SPINLOCK_INIT};
#elif defined(MOZ_MEMORY_LINUX) && !defined(MOZ_MEMORY_ANDROID)
static malloc_mutex_t init_lock = PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP;
#elif defined(MOZ_MEMORY)
static malloc_mutex_t init_lock = PTHREAD_MUTEX_INITIALIZER;
#else
static malloc_mutex_t init_lock = {_SPINLOCK_INITIALIZER};
#endif

/******************************************************************************/
/*
 * Statistics data structures.
 */

#ifdef MALLOC_STATS

typedef struct malloc_bin_stats_s malloc_bin_stats_t;
struct malloc_bin_stats_s {
	/*
	 * Number of allocation requests that corresponded to the size of this
	 * bin.
	 */
	uint64_t	nrequests;

	/* Total number of runs created for this bin's size class. */
	uint64_t	nruns;

	/*
	 * Total number of runs reused by extracting them from the runs tree for
	 * this bin's size class.
	 */
	uint64_t	reruns;

	/* High-water mark for this bin. */
	unsigned long	highruns;

	/* Current number of runs in this bin. */
	unsigned long	curruns;
};

typedef struct arena_stats_s arena_stats_t;
struct arena_stats_s {
	/* Number of bytes currently mapped. */
	size_t		mapped;

	/*
	 * Total number of purge sweeps, total number of madvise calls made,
	 * and total pages purged in order to keep dirty unused memory under
	 * control.
	 */
	uint64_t	npurge;
	uint64_t	nmadvise;
	uint64_t	purged;
#ifdef MALLOC_DECOMMIT
	/*
	 * Total number of decommit/commit operations, and total number of
	 * pages decommitted.
	 */
	uint64_t	ndecommit;
	uint64_t	ncommit;
	uint64_t	decommitted;

	/* Current number of committed pages. */
	size_t		committed;
#endif

	/* Per-size-category statistics. */
	size_t		allocated_small;
	uint64_t	nmalloc_small;
	uint64_t	ndalloc_small;

	size_t		allocated_large;
	uint64_t	nmalloc_large;
	uint64_t	ndalloc_large;

#ifdef MALLOC_BALANCE
	/* Number of times this arena reassigned a thread due to contention. */
	uint64_t	nbalance;
#endif
};

typedef struct chunk_stats_s chunk_stats_t;
struct chunk_stats_s {
	/* Number of chunks that were allocated. */
	uint64_t	nchunks;

	/* High-water mark for number of chunks allocated. */
	unsigned long	highchunks;

	/*
	 * Current number of chunks allocated.  This value isn't maintained for
	 * any other purpose, so keep track of it in order to be able to set
	 * highchunks.
	 */
	unsigned long	curchunks;
};

#endif /* #ifdef MALLOC_STATS */

/******************************************************************************/
/*
 * Extent data structures.
 */

/* Tree of extents. */
typedef struct extent_node_s extent_node_t;
struct extent_node_s {
	/* Linkage for the size/address-ordered tree. */
	rb_node(extent_node_t) link_szad;

	/* Linkage for the address-ordered tree. */
	rb_node(extent_node_t) link_ad;

	/* Pointer to the extent that this tree node is responsible for. */
	void	*addr;

	/* Total region size. */
	size_t	size;
};
typedef rb_tree(extent_node_t) extent_tree_t;

/******************************************************************************/
/*
 * Radix tree data structures.
 */

#ifdef MALLOC_VALIDATE
   /*
    * Size of each radix tree node (must be a power of 2).  This impacts tree
    * depth.
    */
#  if (SIZEOF_PTR == 4)
#    define MALLOC_RTREE_NODESIZE (1U << 14)
#  else
#    define MALLOC_RTREE_NODESIZE CACHELINE
#  endif

typedef struct malloc_rtree_s malloc_rtree_t;
struct malloc_rtree_s {
	malloc_spinlock_t	lock;
	void			**root;
	unsigned		height;
	unsigned		level2bits[1]; /* Dynamically sized. */
};
#endif

/******************************************************************************/
/*
 * Arena data structures.
 */

typedef struct arena_s arena_t;
typedef struct arena_bin_s arena_bin_t;

/* Each element of the chunk map corresponds to one page within the chunk. */
typedef struct arena_chunk_map_s arena_chunk_map_t;
struct arena_chunk_map_s {
	/*
	 * Linkage for run trees.  There are two disjoint uses:
	 *
	 * 1) arena_t's runs_avail tree.
	 * 2) arena_run_t conceptually uses this linkage for in-use non-full
	 *    runs, rather than directly embedding linkage.
	 */
	rb_node(arena_chunk_map_t)	link;

	/*
	 * Run address (or size) and various flags are stored together.  The bit
	 * layout looks like (assuming 32-bit system):
	 *
	 *   ???????? ???????? ????---- --ckdzla
	 *
	 * ? : Unallocated: Run address for first/last pages, unset for internal
	 *                  pages.
	 *     Small: Run address.
	 *     Large: Run size for first page, unset for trailing pages.
	 * - : Unused.
	 * c : decommitted?
	 * k : key?
	 * d : dirty?
	 * z : zeroed?
	 * l : large?
	 * a : allocated?
	 *
	 * Following are example bit patterns for the three types of runs.
	 *
	 * r : run address
	 * s : run size
	 * x : don't care
	 * - : 0
	 * [cdzla] : bit set
	 *
	 *   Unallocated:
	 *     ssssssss ssssssss ssss---- --c-----
	 *     xxxxxxxx xxxxxxxx xxxx---- ----d---
	 *     ssssssss ssssssss ssss---- -----z--
	 *
	 *   Small:
	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
	 *
	 *   Large:
	 *     ssssssss ssssssss ssss---- ------la
	 *     -------- -------- -------- ------la
	 *     -------- -------- -------- ------la
	 */
	size_t				bits;
#ifdef MALLOC_DECOMMIT
#define	CHUNK_MAP_DECOMMITTED	((size_t)0x20U)
#endif
#define	CHUNK_MAP_KEY		((size_t)0x10U)
#define	CHUNK_MAP_DIRTY		((size_t)0x08U)
#define	CHUNK_MAP_ZEROED	((size_t)0x04U)
#define	CHUNK_MAP_LARGE		((size_t)0x02U)
#define	CHUNK_MAP_ALLOCATED	((size_t)0x01U)
};
typedef rb_tree(arena_chunk_map_t) arena_avail_tree_t;
typedef rb_tree(arena_chunk_map_t) arena_run_tree_t;

/* Arena chunk header. */
typedef struct arena_chunk_s arena_chunk_t;
struct arena_chunk_s {
	/* Arena that owns the chunk. */
	arena_t		*arena;

	/* Linkage for the arena's chunks_dirty tree. */
	rb_node(arena_chunk_t) link_dirty;

	/* Number of dirty pages. */
	size_t		ndirty;

	/* Map of pages within chunk that keeps track of free/large/small. */
	arena_chunk_map_t map[1]; /* Dynamically sized. */
};
typedef rb_tree(arena_chunk_t) arena_chunk_tree_t;

typedef struct arena_run_s arena_run_t;
struct arena_run_s {
#ifdef MALLOC_DEBUG
	uint32_t	magic;
#  define ARENA_RUN_MAGIC 0x384adf93
#endif

	/* Bin this run is associated with. */
	arena_bin_t	*bin;

	/* Index of first element that might have a free region. */
	unsigned	regs_minelm;

	/* Number of free regions in run. */
	unsigned	nfree;

	/* Bitmask of in-use regions (0: in use, 1: free). */
	unsigned	regs_mask[1]; /* Dynamically sized. */
};

struct arena_bin_s {
	/*
	 * Current run being used to service allocations of this bin's size
	 * class.
	 */
	arena_run_t	*runcur;

	/*
	 * Tree of non-full runs.  This tree is used when looking for an
	 * existing run when runcur is no longer usable.  We choose the
	 * non-full run that is lowest in memory; this policy tends to keep
	 * objects packed well, and it can also help reduce the number of
	 * almost-empty chunks.
	 */
	arena_run_tree_t runs;

	/* Size of regions in a run for this bin's size class. */
	size_t		reg_size;

	/* Total size of a run for this bin's size class. */
	size_t		run_size;

	/* Total number of regions in a run for this bin's size class. */
	uint32_t	nregs;

	/* Number of elements in a run's regs_mask for this bin's size class. */
	uint32_t	regs_mask_nelms;

	/* Offset of first region in a run for this bin's size class. */
	uint32_t	reg0_offset;

#ifdef MALLOC_STATS
	/* Bin statistics. */
	malloc_bin_stats_t stats;
#endif
};

struct arena_s {
#ifdef MALLOC_DEBUG
	uint32_t		magic;
#  define ARENA_MAGIC 0x947d3d24
#endif

	/* All operations on this arena require that lock be locked. */
#ifdef MOZ_MEMORY
	malloc_spinlock_t	lock;
#else
	pthread_mutex_t		lock;
#endif

#ifdef MALLOC_STATS
	arena_stats_t		stats;
#endif

	/* Tree of dirty-page-containing chunks this arena manages. */
	arena_chunk_tree_t	chunks_dirty;

	/*
	 * In order to avoid rapid chunk allocation/deallocation when an arena
	 * oscillates right on the cusp of needing a new chunk, cache the most
	 * recently freed chunk.  The spare is left in the arena's chunk trees
	 * until it is deleted.
	 *
	 * There is one spare chunk per arena, rather than one spare total, in
	 * order to avoid interactions between multiple threads that could make
	 * a single spare inadequate.
	 */
	arena_chunk_t		*spare;

	/*
	 * Current count of pages within unused runs that are potentially
	 * dirty, and for which madvise(... MADV_FREE) has not been called.  By
	 * tracking this, we can institute a limit on how much dirty unused
	 * memory is mapped for each arena.
	 */
	size_t			ndirty;

	/*
	 * Size/address-ordered tree of this arena's available runs.  This tree
	 * is used for first-best-fit run allocation.
	 */
	arena_avail_tree_t	runs_avail;

#ifdef MALLOC_BALANCE
	/*
	 * The arena load balancing machinery needs to keep track of how much
	 * lock contention there is.  This value is exponentially averaged.
	 */
	uint32_t		contention;
#endif

	/*
	 * bins is used to store rings of free regions of the following sizes,
	 * assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS.
	 *
	 *   bins[i] | size |
	 *   --------+------+
	 *        0  |    2 |
	 *        1  |    4 |
	 *        2  |    8 |
	 *   --------+------+
	 *        3  |   16 |
	 *        4  |   32 |
	 *        5  |   48 |
	 *        6  |   64 |
	 *           :      :
	 *           :      :
	 *       33  |  496 |
	 *       34  |  512 |
	 *   --------+------+
	 *       35  | 1024 |
	 *       36  | 2048 |
	 *   --------+------+
	 */
	arena_bin_t		bins[1]; /* Dynamically sized. */
};

/******************************************************************************/
/*
 * Data.
 */

#ifndef MOZ_MEMORY_NARENAS_DEFAULT_ONE
/* Number of CPUs. */
static unsigned		ncpus;
#endif

/* VM page size. */
static size_t		pagesize;
static size_t		pagesize_mask;
static size_t		pagesize_2pow;

/* Various bin-related settings. */
static size_t		bin_maxclass; /* Max size class for bins. */
static unsigned		ntbins; /* Number of (2^n)-spaced tiny bins. */
static unsigned		nqbins; /* Number of quantum-spaced bins. */
static unsigned		nsbins; /* Number of (2^n)-spaced sub-page bins. */
static size_t		small_min;
static size_t		small_max;

/* Various quantum-related settings. */
static size_t		quantum;
static size_t		quantum_mask; /* (quantum - 1). */

/* Various chunk-related settings. */
static size_t		chunksize;
static size_t		chunksize_mask; /* (chunksize - 1). */
static size_t		chunk_npages;
static size_t		arena_chunk_header_npages;
static size_t		arena_maxclass; /* Max size class for arenas. */

/********/
/*
 * Chunks.
 */

#ifdef MALLOC_VALIDATE
static malloc_rtree_t *chunk_rtree;
#endif

/* Protects chunk-related data structures. */
static malloc_mutex_t	huge_mtx;

/* Tree of chunks that are stand-alone huge allocations. */
static extent_tree_t	huge;

#ifdef MALLOC_STATS
/* Huge allocation statistics. */
static uint64_t		huge_nmalloc;
static uint64_t		huge_ndalloc;
static size_t		huge_allocated;
#endif

#ifdef MALLOC_PAGEFILE
static char		pagefile_templ[PATH_MAX];
#endif

/****************************/
/*
 * base (internal allocation).
 */

/*
 * Current pages that are being used for internal memory allocations.  These
 * pages are carved up in cacheline-size quanta, so that there is no chance of
 * false cache line sharing.
 */
static void		*base_pages;
static void		*base_next_addr;
#ifdef MALLOC_DECOMMIT
static void		*base_next_decommitted;
#endif
static void		*base_past_addr; /* Addr immediately past base_pages. */
static extent_node_t	*base_nodes;
static malloc_mutex_t	base_mtx;
#ifdef MALLOC_STATS
static size_t		base_mapped;
#  ifdef MALLOC_DECOMMIT
static size_t		base_committed;
#  endif
#endif

/********/
/*
 * Arenas.
 */

/*
 * Arenas that are used to service external requests.  Not all elements of the
 * arenas array are necessarily used; arenas are created lazily as needed.
 */
static arena_t		**arenas;
static unsigned		narenas;
#ifndef NO_TLS
#  ifdef MALLOC_BALANCE
static unsigned		narenas_2pow;
#  else
static unsigned		next_arena;
#  endif
#endif
#ifdef MOZ_MEMORY
static malloc_spinlock_t arenas_lock; /* Protects arenas initialization. */
#else
static pthread_mutex_t arenas_lock; /* Protects arenas initialization. */
#endif

#ifndef NO_TLS
/*
 * Map of pthread_self() --> arenas[???], used for selecting an arena to use
 * for allocations.
 */
#ifndef MOZ_MEMORY_WINDOWS
static __thread arena_t	*arenas_map;
#endif
#endif

#ifdef MALLOC_STATS
/* Chunk statistics. */
static chunk_stats_t	stats_chunks;
#endif

/*******************************/
/*
 * Runtime configuration options.
 */
const char	*_malloc_options;

#ifndef MALLOC_PRODUCTION
static bool	opt_abort = true;
#ifdef MALLOC_FILL
static bool	opt_junk = true;
#endif
#else
static bool	opt_abort = false;
#ifdef MALLOC_FILL
static bool	opt_junk = false;
#endif
#endif
static size_t	opt_dirty_max = DIRTY_MAX_DEFAULT;
#ifdef MALLOC_BALANCE
static uint64_t	opt_balance_threshold = BALANCE_THRESHOLD_DEFAULT;
#endif
static bool	opt_print_stats = false;
static size_t	opt_quantum_2pow = QUANTUM_2POW_MIN;
static size_t	opt_small_max_2pow = SMALL_MAX_2POW_DEFAULT;
static size_t	opt_chunk_2pow = CHUNK_2POW_DEFAULT;
#ifdef MALLOC_PAGEFILE
static bool	opt_pagefile = false;
#endif
#ifdef MALLOC_UTRACE
static bool	opt_utrace = false;
#endif
#ifdef MALLOC_SYSV
static bool	opt_sysv = false;
#endif
#ifdef MALLOC_XMALLOC
static bool	opt_xmalloc = false;
#endif
#ifdef MALLOC_FILL
static bool	opt_zero = false;
#endif
static int	opt_narenas_lshift = 0;

#ifdef MALLOC_UTRACE
typedef struct {
	void	*p;
	size_t	s;
	void	*r;
} malloc_utrace_t;

#define	UTRACE(a, b, c)							\
	if (opt_utrace) {						\
		malloc_utrace_t ut;					\
		ut.p = (a);						\
		ut.s = (b);						\
		ut.r = (c);						\
		utrace(&ut, sizeof(ut));				\
	}
#else
#define	UTRACE(a, b, c)
#endif

/******************************************************************************/
/*
 * Begin function prototypes for non-inline static functions.
 */

static char	*umax2s(uintmax_t x, char *s);
static bool	malloc_mutex_init(malloc_mutex_t *mutex);
static bool	malloc_spin_init(malloc_spinlock_t *lock);
static void	wrtmessage(const char *p1, const char *p2, const char *p3,
		const char *p4);
#ifdef MALLOC_STATS
#ifdef MOZ_MEMORY_DARWIN
/* Avoid namespace collision with OS X's malloc APIs. */
#define malloc_printf moz_malloc_printf
#endif
static void	malloc_printf(const char *format, ...);
#endif
static bool	base_pages_alloc_mmap(size_t minsize);
static bool	base_pages_alloc(size_t minsize);
static void	*base_alloc(size_t size);
static void	*base_calloc(size_t number, size_t size);
static extent_node_t *base_node_alloc(void);
static void	base_node_dealloc(extent_node_t *node);
#ifdef MALLOC_STATS
static void	stats_print(arena_t *arena);
#endif
static void	*pages_map(void *addr, size_t size, int pfd);
static void	pages_unmap(void *addr, size_t size);
static void	*chunk_alloc_mmap(size_t size, bool pagefile);
#ifdef MALLOC_PAGEFILE
static int	pagefile_init(size_t size);
static void	pagefile_close(int pfd);
#endif
static void	*chunk_alloc(size_t size, bool zero, bool pagefile);
static void	chunk_dealloc_mmap(void *chunk, size_t size);
static void	chunk_dealloc(void *chunk, size_t size);
#ifndef NO_TLS
static arena_t	*choose_arena_hard(void);
#endif
static void	arena_run_split(arena_t *arena, arena_run_t *run, size_t size,
    bool large, bool zero);
static void arena_chunk_init(arena_t *arena, arena_chunk_t *chunk);
static void	arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk);
static arena_run_t *arena_run_alloc(arena_t *arena, arena_bin_t *bin,
    size_t size, bool large, bool zero);
static void	arena_purge(arena_t *arena);
static void	arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty);
static void	arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk,
    arena_run_t *run, size_t oldsize, size_t newsize);
static void	arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk,
    arena_run_t *run, size_t oldsize, size_t newsize, bool dirty);
static arena_run_t *arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin);
static void *arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin);
static size_t arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size);
#ifdef MALLOC_BALANCE
static void	arena_lock_balance_hard(arena_t *arena);
#endif
static void	*arena_malloc_large(arena_t *arena, size_t size, bool zero);
static void	*arena_palloc(arena_t *arena, size_t alignment, size_t size,
    size_t alloc_size);
static size_t	arena_salloc(const void *ptr);
static void	arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk,
    void *ptr);
static void	arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk,
    void *ptr, size_t size, size_t oldsize);
static bool	arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk,
    void *ptr, size_t size, size_t oldsize);
static bool	arena_ralloc_large(void *ptr, size_t size, size_t oldsize);
static void	*arena_ralloc(void *ptr, size_t size, size_t oldsize);
static bool	arena_new(arena_t *arena);
static arena_t	*arenas_extend(unsigned ind);
static void	*huge_malloc(size_t size, bool zero);
static void	*huge_palloc(size_t alignment, size_t size);
static void	*huge_ralloc(void *ptr, size_t size, size_t oldsize);
static void	huge_dalloc(void *ptr);
static void	malloc_print_stats(void);
#ifndef MOZ_MEMORY_WINDOWS
static
#endif
bool		malloc_init_hard(void);

void		_malloc_prefork(void);
void		_malloc_postfork(void);

/*
 * End function prototypes.
 */
/******************************************************************************/

/*
 * umax2s() provides minimal integer printing functionality, which is
 * especially useful for situations where allocation in vsnprintf() calls would
 * potentially cause deadlock.
 */
#define	UMAX2S_BUFSIZE	21
static char *
umax2s(uintmax_t x, char *s)
{
	unsigned i;

	i = UMAX2S_BUFSIZE - 1;
	s[i] = '\0';
	do {
		i--;
		s[i] = "0123456789"[x % 10];
		x /= 10;
	} while (x > 0);

	return (&s[i]);
}

static void
wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4)
{
#ifdef MOZ_MEMORY_WINCE
       wchar_t buf[1024];
#define WRT_PRINT(s) \
       MultiByteToWideChar(CP_ACP, 0, s, -1, buf, 1024); \
       OutputDebugStringW(buf)

       WRT_PRINT(p1);
       WRT_PRINT(p2);
       WRT_PRINT(p3);
       WRT_PRINT(p4);
#else
#if defined(MOZ_MEMORY) && !defined(MOZ_MEMORY_WINDOWS)
#define	_write	write
#endif
	_write(STDERR_FILENO, p1, (unsigned int) strlen(p1));
	_write(STDERR_FILENO, p2, (unsigned int) strlen(p2));
	_write(STDERR_FILENO, p3, (unsigned int) strlen(p3));
	_write(STDERR_FILENO, p4, (unsigned int) strlen(p4));
#endif

}

#define _malloc_message malloc_message

void	(*_malloc_message)(const char *p1, const char *p2, const char *p3,
	    const char *p4) = wrtmessage;

#ifdef MALLOC_DEBUG
#  define assert(e) do {						\
	if (!(e)) {							\
		char line_buf[UMAX2S_BUFSIZE];				\
		_malloc_message(__FILE__, ":", umax2s(__LINE__,		\
		    line_buf), ": Failed assertion: ");			\
		_malloc_message("\"", #e, "\"\n", "");			\
		abort();						\
	}								\
} while (0)
#else
#define assert(e)
#endif

/******************************************************************************/
/*
 * Begin mutex.  We can't use normal pthread mutexes in all places, because
 * they require malloc()ed memory, which causes bootstrapping issues in some
 * cases.
 */

static bool
malloc_mutex_init(malloc_mutex_t *mutex)
{
#if defined(MOZ_MEMORY_WINCE)
	InitializeCriticalSection(mutex);
#elif defined(MOZ_MEMORY_WINDOWS)
	if (__isthreaded)
		if (! __crtInitCritSecAndSpinCount(mutex, _CRT_SPINCOUNT))
			return (true);
#elif defined(MOZ_MEMORY_DARWIN)
	mutex->lock = OS_SPINLOCK_INIT;
#elif defined(MOZ_MEMORY_LINUX) && !defined(MOZ_MEMORY_ANDROID)
	pthread_mutexattr_t attr;
	if (pthread_mutexattr_init(&attr) != 0)
		return (true);
	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
	if (pthread_mutex_init(mutex, &attr) != 0) {
		pthread_mutexattr_destroy(&attr);
		return (true);
	}
	pthread_mutexattr_destroy(&attr);
#elif defined(MOZ_MEMORY)
	if (pthread_mutex_init(mutex, NULL) != 0)
		return (true);
#else
	static const spinlock_t lock = _SPINLOCK_INITIALIZER;

	mutex->lock = lock;
#endif
	return (false);
}

static inline void
malloc_mutex_lock(malloc_mutex_t *mutex)
{

#if defined(MOZ_MEMORY_WINDOWS)
	EnterCriticalSection(mutex);
#elif defined(MOZ_MEMORY_DARWIN)
	OSSpinLockLock(&mutex->lock);
#elif defined(MOZ_MEMORY)
	pthread_mutex_lock(mutex);
#else
	if (__isthreaded)
		_SPINLOCK(&mutex->lock);
#endif
}

static inline void
malloc_mutex_unlock(malloc_mutex_t *mutex)
{

#if defined(MOZ_MEMORY_WINDOWS)
	LeaveCriticalSection(mutex);
#elif defined(MOZ_MEMORY_DARWIN)
	OSSpinLockUnlock(&mutex->lock);
#elif defined(MOZ_MEMORY)
	pthread_mutex_unlock(mutex);
#else
	if (__isthreaded)
		_SPINUNLOCK(&mutex->lock);
#endif
}

static bool
malloc_spin_init(malloc_spinlock_t *lock)
{
#if defined(MOZ_MEMORY_WINCE)
	InitializeCriticalSection(lock);
#elif defined(MOZ_MEMORY_WINDOWS)
	if (__isthreaded)
		if (! __crtInitCritSecAndSpinCount(lock, _CRT_SPINCOUNT))
			return (true);
#elif defined(MOZ_MEMORY_DARWIN)
	lock->lock = OS_SPINLOCK_INIT;
#elif defined(MOZ_MEMORY_LINUX) && !defined(MOZ_MEMORY_ANDROID)
	pthread_mutexattr_t attr;
	if (pthread_mutexattr_init(&attr) != 0)
		return (true);
	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
	if (pthread_mutex_init(lock, &attr) != 0) {
		pthread_mutexattr_destroy(&attr);
		return (true);
	}
	pthread_mutexattr_destroy(&attr);
#elif defined(MOZ_MEMORY)
	if (pthread_mutex_init(lock, NULL) != 0)
		return (true);
#else
	lock->lock = _SPINLOCK_INITIALIZER;
#endif
	return (false);
}

static inline void
malloc_spin_lock(malloc_spinlock_t *lock)
{

#if defined(MOZ_MEMORY_WINDOWS)
	EnterCriticalSection(lock);
#elif defined(MOZ_MEMORY_DARWIN)
	OSSpinLockLock(&lock->lock);
#elif defined(MOZ_MEMORY)
	pthread_mutex_lock(lock);
#else
	if (__isthreaded)
		_SPINLOCK(&lock->lock);
#endif
}

static inline void
malloc_spin_unlock(malloc_spinlock_t *lock)
{
#if defined(MOZ_MEMORY_WINDOWS)
	LeaveCriticalSection(lock);
#elif defined(MOZ_MEMORY_DARWIN)
	OSSpinLockUnlock(&lock->lock);
#elif defined(MOZ_MEMORY)
	pthread_mutex_unlock(lock);
#else
	if (__isthreaded)
		_SPINUNLOCK(&lock->lock);
#endif
}

/*
 * End mutex.
 */
/******************************************************************************/
/*
 * Begin spin lock.  Spin locks here are actually adaptive mutexes that block
 * after a period of spinning, because unbounded spinning would allow for
 * priority inversion.
 */

#if defined(MOZ_MEMORY) && !defined(MOZ_MEMORY_DARWIN)
#  define	malloc_spin_init	malloc_mutex_init
#  define	malloc_spin_lock	malloc_mutex_lock
#  define	malloc_spin_unlock	malloc_mutex_unlock
#endif

#ifndef MOZ_MEMORY
/*
 * We use an unpublished interface to initialize pthread mutexes with an
 * allocation callback, in order to avoid infinite recursion.
 */
int	_pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
    void *(calloc_cb)(size_t, size_t));

__weak_reference(_pthread_mutex_init_calloc_cb_stub,
    _pthread_mutex_init_calloc_cb);

int
_pthread_mutex_init_calloc_cb_stub(pthread_mutex_t *mutex,
    void *(calloc_cb)(size_t, size_t))
{

	return (0);
}

static bool
malloc_spin_init(pthread_mutex_t *lock)
{

	if (_pthread_mutex_init_calloc_cb(lock, base_calloc) != 0)
		return (true);

	return (false);
}

static inline unsigned
malloc_spin_lock(pthread_mutex_t *lock)
{
	unsigned ret = 0;

	if (__isthreaded) {
		if (_pthread_mutex_trylock(lock) != 0) {
			unsigned i;
			volatile unsigned j;

			/* Exponentially back off. */
			for (i = 1; i <= SPIN_LIMIT_2POW; i++) {
				for (j = 0; j < (1U << i); j++)
					ret++;

				CPU_SPINWAIT;
				if (_pthread_mutex_trylock(lock) == 0)
					return (ret);
			}

			/*
			 * Spinning failed.  Block until the lock becomes
			 * available, in order to avoid indefinite priority
			 * inversion.
			 */
			_pthread_mutex_lock(lock);
			assert((ret << BLOCK_COST_2POW) != 0);
			return (ret << BLOCK_COST_2POW);
		}
	}

	return (ret);
}

static inline void
malloc_spin_unlock(pthread_mutex_t *lock)
{

	if (__isthreaded)
		_pthread_mutex_unlock(lock);
}
#endif

/*
 * End spin lock.
 */
/******************************************************************************/
/*
 * Begin Utility functions/macros.
 */

/* Return the chunk address for allocation address a. */
#define	CHUNK_ADDR2BASE(a)						\
	((void *)((uintptr_t)(a) & ~chunksize_mask))

/* Return the chunk offset of address a. */
#define	CHUNK_ADDR2OFFSET(a)						\
	((size_t)((uintptr_t)(a) & chunksize_mask))

/* Return the smallest chunk multiple that is >= s. */
#define	CHUNK_CEILING(s)						\
	(((s) + chunksize_mask) & ~chunksize_mask)

/* Return the smallest cacheline multiple that is >= s. */
#define	CACHELINE_CEILING(s)						\
	(((s) + (CACHELINE - 1)) & ~(CACHELINE - 1))

/* Return the smallest quantum multiple that is >= a. */
#define	QUANTUM_CEILING(a)						\
	(((a) + quantum_mask) & ~quantum_mask)

/* Return the smallest pagesize multiple that is >= s. */
#define	PAGE_CEILING(s)							\
	(((s) + pagesize_mask) & ~pagesize_mask)

/* Compute the smallest power of 2 that is >= x. */
static inline size_t
pow2_ceil(size_t x)
{

	x--;
	x |= x >> 1;
	x |= x >> 2;
	x |= x >> 4;
	x |= x >> 8;
	x |= x >> 16;
#if (SIZEOF_PTR == 8)
	x |= x >> 32;
#endif
	x++;
	return (x);
}

#ifdef MALLOC_BALANCE
/*
 * Use a simple linear congruential pseudo-random number generator:
 *
 *   prn(y) = (a*x + c) % m
 *
 * where the following constants ensure maximal period:
 *
 *   a == Odd number (relatively prime to 2^n), and (a-1) is a multiple of 4.
 *   c == Odd number (relatively prime to 2^n).
 *   m == 2^32
 *
 * See Knuth's TAOCP 3rd Ed., Vol. 2, pg. 17 for details on these constraints.
 *
 * This choice of m has the disadvantage that the quality of the bits is
 * proportional to bit position.  For example. the lowest bit has a cycle of 2,
 * the next has a cycle of 4, etc.  For this reason, we prefer to use the upper
 * bits.
 */
#  define PRN_DEFINE(suffix, var, a, c)					\
static inline void							\
sprn_##suffix(uint32_t seed)						\
{									\
	var = seed;							\
}									\
									\
static inline uint32_t							\
prn_##suffix(uint32_t lg_range)						\
{									\
	uint32_t ret, x;						\
									\
	assert(lg_range > 0);						\
	assert(lg_range <= 32);						\
									\
	x = (var * (a)) + (c);						\
	var = x;							\
	ret = x >> (32 - lg_range);					\
									\
	return (ret);							\
}
#  define SPRN(suffix, seed)	sprn_##suffix(seed)
#  define PRN(suffix, lg_range)	prn_##suffix(lg_range)
#endif

#ifdef MALLOC_BALANCE
/* Define the PRNG used for arena assignment. */
static __thread uint32_t balance_x;
PRN_DEFINE(balance, balance_x, 1297, 1301)
#endif

#ifdef MALLOC_UTRACE
static int
utrace(const void *addr, size_t len)
{
	malloc_utrace_t *ut = (malloc_utrace_t *)addr;

	assert(len == sizeof(malloc_utrace_t));

	if (ut->p == NULL && ut->s == 0 && ut->r == NULL)
		malloc_printf("%d x USER malloc_init()\n", getpid());
	else if (ut->p == NULL && ut->r != NULL) {
		malloc_printf("%d x USER %p = malloc(%zu)\n", getpid(), ut->r,
		    ut->s);
	} else if (ut->p != NULL && ut->r != NULL) {
		malloc_printf("%d x USER %p = realloc(%p, %zu)\n", getpid(),
		    ut->r, ut->p, ut->s);
	} else
		malloc_printf("%d x USER free(%p)\n", getpid(), ut->p);

	return (0);
}
#endif

static inline const char *
_getprogname(void)
{

	return ("<jemalloc>");
}

#ifdef MALLOC_STATS
/*
 * Print to stderr in such a way as to (hopefully) avoid memory allocation.
 */
static void
malloc_printf(const char *format, ...)
{
#ifndef WINCE
	char buf[4096];
	va_list ap;

	va_start(ap, format);
	vsnprintf(buf, sizeof(buf), format, ap);
	va_end(ap);
	_malloc_message(buf, "", "", "");
#endif
}
#endif

/******************************************************************************/

#ifdef MALLOC_DECOMMIT
static inline void
pages_decommit(void *addr, size_t size)
{

#ifdef MOZ_MEMORY_WINDOWS
	VirtualFree(addr, size, MEM_DECOMMIT);
#else
	if (mmap(addr, size, PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON, -1,
	    0) == MAP_FAILED)
		abort();
#endif
}

static inline void
pages_commit(void *addr, size_t size)
{

#  ifdef MOZ_MEMORY_WINDOWS
	VirtualAlloc(addr, size, MEM_COMMIT, PAGE_READWRITE);
#  else
	if (mmap(addr, size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE |
	    MAP_ANON, -1, 0) == MAP_FAILED)
		abort();
#  endif
}
#endif

static bool
base_pages_alloc_mmap(size_t minsize)
{
	bool ret;
	size_t csize;
#ifdef MALLOC_DECOMMIT
	size_t pminsize;
#endif
	int pfd;

	assert(minsize != 0);
	csize = CHUNK_CEILING(minsize);
#ifdef MALLOC_PAGEFILE
	if (opt_pagefile) {
		pfd = pagefile_init(csize);
		if (pfd == -1)
			return (true);
	} else
#endif
		pfd = -1;
	base_pages = pages_map(NULL, csize, pfd);
	if (base_pages == NULL) {
		ret = true;
		goto RETURN;
	}
	base_next_addr = base_pages;
	base_past_addr = (void *)((uintptr_t)base_pages + csize);
#ifdef MALLOC_DECOMMIT
	/*
	 * Leave enough pages for minsize committed, since otherwise they would
	 * have to be immediately recommitted.
	 */
	pminsize = PAGE_CEILING(minsize);
	base_next_decommitted = (void *)((uintptr_t)base_pages + pminsize);
	if (pminsize < csize)
		pages_decommit(base_next_decommitted, csize - pminsize);
#endif
#ifdef MALLOC_STATS
	base_mapped += csize;
#  ifdef MALLOC_DECOMMIT
	base_committed += pminsize;
#  endif
#endif

	ret = false;
RETURN:
#ifdef MALLOC_PAGEFILE
	if (pfd != -1)
		pagefile_close(pfd);
#endif
	return (false);
}

static bool
base_pages_alloc(size_t minsize)
{

	if (base_pages_alloc_mmap(minsize) == false)
		return (false);

	return (true);
}

static void *
base_alloc(size_t size)
{
	void *ret;
	size_t csize;

	/* Round size up to nearest multiple of the cacheline size. */
	csize = CACHELINE_CEILING(size);

	malloc_mutex_lock(&base_mtx);
	/* Make sure there's enough space for the allocation. */
	if ((uintptr_t)base_next_addr + csize > (uintptr_t)base_past_addr) {
		if (base_pages_alloc(csize)) {
			malloc_mutex_unlock(&base_mtx);
			return (NULL);
		}
	}
	/* Allocate. */
	ret = base_next_addr;
	base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
#ifdef MALLOC_DECOMMIT
	/* Make sure enough pages are committed for the new allocation. */
	if ((uintptr_t)base_next_addr > (uintptr_t)base_next_decommitted) {
		void *pbase_next_addr =
		    (void *)(PAGE_CEILING((uintptr_t)base_next_addr));

		pages_commit(base_next_decommitted, (uintptr_t)pbase_next_addr -
		    (uintptr_t)base_next_decommitted);
		base_next_decommitted = pbase_next_addr;
#  ifdef MALLOC_STATS
		base_committed += (uintptr_t)pbase_next_addr -
		    (uintptr_t)base_next_decommitted;
#  endif
	}
#endif
	malloc_mutex_unlock(&base_mtx);
	VALGRIND_MALLOCLIKE_BLOCK(ret, size, 0, false);

	return (ret);
}

static void *
base_calloc(size_t number, size_t size)
{
	void *ret;

	ret = base_alloc(number * size);
#ifdef MALLOC_VALGRIND
	if (ret != NULL) {
		VALGRIND_FREELIKE_BLOCK(ret, 0);
		VALGRIND_MALLOCLIKE_BLOCK(ret, size, 0, true);
	}
#endif
	memset(ret, 0, number * size);

	return (ret);
}

static extent_node_t *
base_node_alloc(void)
{
	extent_node_t *ret;

	malloc_mutex_lock(&base_mtx);
	if (base_nodes != NULL) {
		ret = base_nodes;
		base_nodes = *(extent_node_t **)ret;
		VALGRIND_FREELIKE_BLOCK(ret, 0);
		VALGRIND_MALLOCLIKE_BLOCK(ret, sizeof(extent_node_t), 0, false);
		malloc_mutex_unlock(&base_mtx);
	} else {
		malloc_mutex_unlock(&base_mtx);
		ret = (extent_node_t *)base_alloc(sizeof(extent_node_t));
	}

	return (ret);
}

static void
base_node_dealloc(extent_node_t *node)
{

	malloc_mutex_lock(&base_mtx);
	VALGRIND_FREELIKE_BLOCK(node, 0);
	VALGRIND_MALLOCLIKE_BLOCK(node, sizeof(extent_node_t *), 0, false);
	*(extent_node_t **)node = base_nodes;
	base_nodes = node;
	malloc_mutex_unlock(&base_mtx);
}

/******************************************************************************/

#ifdef MALLOC_STATS
static void
stats_print(arena_t *arena)
{
	unsigned i, gap_start;

#ifdef MOZ_MEMORY_WINDOWS
	malloc_printf("dirty: %Iu page%s dirty, %I64u sweep%s,"
	    " %I64u madvise%s, %I64u page%s purged\n",
	    arena->ndirty, arena->ndirty == 1 ? "" : "s",
	    arena->stats.npurge, arena->stats.npurge == 1 ? "" : "s",
	    arena->stats.nmadvise, arena->stats.nmadvise == 1 ? "" : "s",
	    arena->stats.purged, arena->stats.purged == 1 ? "" : "s");
#  ifdef MALLOC_DECOMMIT
	malloc_printf("decommit: %I64u decommit%s, %I64u commit%s,"
	    " %I64u page%s decommitted\n",
	    arena->stats.ndecommit, (arena->stats.ndecommit == 1) ? "" : "s",
	    arena->stats.ncommit, (arena->stats.ncommit == 1) ? "" : "s",
	    arena->stats.decommitted,
	    (arena->stats.decommitted == 1) ? "" : "s");
#  endif

	malloc_printf("            allocated      nmalloc      ndalloc\n");
	malloc_printf("small:   %12Iu %12I64u %12I64u\n",
	    arena->stats.allocated_small, arena->stats.nmalloc_small,
	    arena->stats.ndalloc_small);
	malloc_printf("large:   %12Iu %12I64u %12I64u\n",
	    arena->stats.allocated_large, arena->stats.nmalloc_large,
	    arena->stats.ndalloc_large);
	malloc_printf("total:   %12Iu %12I64u %12I64u\n",
	    arena->stats.allocated_small + arena->stats.allocated_large,
	    arena->stats.nmalloc_small + arena->stats.nmalloc_large,
	    arena->stats.ndalloc_small + arena->stats.ndalloc_large);
	malloc_printf("mapped:  %12Iu\n", arena->stats.mapped);
#else
	malloc_printf("dirty: %zu page%s dirty, %llu sweep%s,"
	    " %llu madvise%s, %llu page%s purged\n",
	    arena->ndirty, arena->ndirty == 1 ? "" : "s",
	    arena->stats.npurge, arena->stats.npurge == 1 ? "" : "s",
	    arena->stats.nmadvise, arena->stats.nmadvise == 1 ? "" : "s",
	    arena->stats.purged, arena->stats.purged == 1 ? "" : "s");
#  ifdef MALLOC_DECOMMIT
	malloc_printf("decommit: %llu decommit%s, %llu commit%s,"
	    " %llu page%s decommitted\n",
	    arena->stats.ndecommit, (arena->stats.ndecommit == 1) ? "" : "s",
	    arena->stats.ncommit, (arena->stats.ncommit == 1) ? "" : "s",
	    arena->stats.decommitted,
	    (arena->stats.decommitted == 1) ? "" : "s");
#  endif

	malloc_printf("            allocated      nmalloc      ndalloc\n");
	malloc_printf("small:   %12zu %12llu %12llu\n",
	    arena->stats.allocated_small, arena->stats.nmalloc_small,
	    arena->stats.ndalloc_small);
	malloc_printf("large:   %12zu %12llu %12llu\n",
	    arena->stats.allocated_large, arena->stats.nmalloc_large,
	    arena->stats.ndalloc_large);
	malloc_printf("total:   %12zu %12llu %12llu\n",
	    arena->stats.allocated_small + arena->stats.allocated_large,
	    arena->stats.nmalloc_small + arena->stats.nmalloc_large,
	    arena->stats.ndalloc_small + arena->stats.ndalloc_large);
	malloc_printf("mapped:  %12zu\n", arena->stats.mapped);
#endif
	malloc_printf("bins:     bin   size regs pgs  requests   newruns"
	    "    reruns maxruns curruns\n");
	for (i = 0, gap_start = UINT_MAX; i < ntbins + nqbins + nsbins; i++) {
		if (arena->bins[i].stats.nrequests == 0) {
			if (gap_start == UINT_MAX)
				gap_start = i;
		} else {
			if (gap_start != UINT_MAX) {
				if (i > gap_start + 1) {
					/* Gap of more than one size class. */
					malloc_printf("[%u..%u]\n",
					    gap_start, i - 1);
				} else {
					/* Gap of one size class. */
					malloc_printf("[%u]\n", gap_start);
				}
				gap_start = UINT_MAX;
			}
			malloc_printf(
#if defined(MOZ_MEMORY_WINDOWS)
			    "%13u %1s %4u %4u %3u %9I64u %9I64u"
			    " %9I64u %7u %7u\n",
#else
			    "%13u %1s %4u %4u %3u %9llu %9llu"
			    " %9llu %7lu %7lu\n",
#endif
			    i,
			    i < ntbins ? "T" : i < ntbins + nqbins ? "Q" : "S",
			    arena->bins[i].reg_size,
			    arena->bins[i].nregs,
			    arena->bins[i].run_size >> pagesize_2pow,
			    arena->bins[i].stats.nrequests,
			    arena->bins[i].stats.nruns,
			    arena->bins[i].stats.reruns,
			    arena->bins[i].stats.highruns,
			    arena->bins[i].stats.curruns);
		}
	}
	if (gap_start != UINT_MAX) {
		if (i > gap_start + 1) {
			/* Gap of more than one size class. */
			malloc_printf("[%u..%u]\n", gap_start, i - 1);
		} else {
			/* Gap of one size class. */
			malloc_printf("[%u]\n", gap_start);
		}
	}
}
#endif

/*
 * End Utility functions/macros.
 */
/******************************************************************************/
/*
 * Begin extent tree code.
 */

static inline int
extent_szad_comp(extent_node_t *a, extent_node_t *b)
{
	int ret;
	size_t a_size = a->size;
	size_t b_size = b->size;

	ret = (a_size > b_size) - (a_size < b_size);
	if (ret == 0) {
		uintptr_t a_addr = (uintptr_t)a->addr;
		uintptr_t b_addr = (uintptr_t)b->addr;

		ret = (a_addr > b_addr) - (a_addr < b_addr);
	}

	return (ret);
}

/* Wrap red-black tree macros in functions. */
rb_wrap(static, extent_tree_szad_, extent_tree_t, extent_node_t,
    link_szad, extent_szad_comp)

static inline int
extent_ad_comp(extent_node_t *a, extent_node_t *b)
{
	uintptr_t a_addr = (uintptr_t)a->addr;
	uintptr_t b_addr = (uintptr_t)b->addr;

	return ((a_addr > b_addr) - (a_addr < b_addr));
}

/* Wrap red-black tree macros in functions. */
rb_wrap(static, extent_tree_ad_, extent_tree_t, extent_node_t, link_ad,
    extent_ad_comp)

/*
 * End extent tree code.
 */
/******************************************************************************/
/*
 * Begin chunk management functions.
 */

#ifdef MOZ_MEMORY_WINDOWS
#ifdef MOZ_MEMORY_WINCE
#define ALIGN_ADDR2OFFSET(al, ad) \
	((uintptr_t)ad & (al - 1))
static void *
pages_map_align(size_t size, int pfd, size_t alignment)
{
	
	void *ret; 
	int offset;
	if (size % alignment)
		size += (alignment - (size % alignment));
	assert(size >= alignment);
	ret = pages_map(NULL, size, pfd);
	offset = ALIGN_ADDR2OFFSET(alignment, ret);
	if (offset) {  
		/* try to over allocate by the ammount we're offset */
		void *tmp;
		pages_unmap(ret, size);
		tmp = VirtualAlloc(NULL, size + alignment - offset, 
					 MEM_RESERVE, PAGE_NOACCESS);
		if (offset == ALIGN_ADDR2OFFSET(alignment, tmp))
			ret = VirtualAlloc((void*)((intptr_t)tmp + alignment 
						   - offset), size, MEM_COMMIT,
					   PAGE_READWRITE);
		else 
			VirtualFree(tmp, 0, MEM_RELEASE);
		offset = ALIGN_ADDR2OFFSET(alignment, ret);
		
	
		if (offset) {  
			/* over allocate to ensure we have an aligned region */
			ret = VirtualAlloc(NULL, size + alignment, MEM_RESERVE, 
					   PAGE_NOACCESS);
			offset = ALIGN_ADDR2OFFSET(alignment, ret);
			ret = VirtualAlloc((void*)((intptr_t)ret + 
						   alignment - offset),
					   size, MEM_COMMIT, PAGE_READWRITE);
		}
	}
	return (ret);
}
#endif

static void *
pages_map(void *addr, size_t size, int pfd)
{
	void *ret = NULL;
#if defined(MOZ_MEMORY_WINCE) && !defined(MOZ_MEMORY_WINCE6)
	void *va_ret;
	assert(addr == NULL);
	va_ret = VirtualAlloc(addr, size, MEM_RESERVE, PAGE_NOACCESS);
	if (va_ret)
		ret = VirtualAlloc(va_ret, size, MEM_COMMIT, PAGE_READWRITE);
	assert(va_ret == ret);
#else
	ret = VirtualAlloc(addr, size, MEM_COMMIT | MEM_RESERVE,
	    PAGE_READWRITE);
#endif
	return (ret);
}

static void
pages_unmap(void *addr, size_t size)
{
	if (VirtualFree(addr, 0, MEM_RELEASE) == 0) {
#if defined(MOZ_MEMORY_WINCE) && !defined(MOZ_MEMORY_WINCE6)
		if (GetLastError() == ERROR_INVALID_PARAMETER) {
			MEMORY_BASIC_INFORMATION info;
			VirtualQuery(addr, &info, sizeof(info));
			if (VirtualFree(info.AllocationBase, 0, MEM_RELEASE))
				return;
		}
#endif
		_malloc_message(_getprogname(),
		    ": (malloc) Error in VirtualFree()\n", "", "");
		if (opt_abort)
			abort();
	}
}
#elif (defined(MOZ_MEMORY_DARWIN))
static void *
pages_map(void *addr, size_t size, int pfd)
{
	void *ret;
	kern_return_t err;
	int flags;

	if (addr != NULL) {
		ret = addr;
		flags = 0;
	} else
		flags = VM_FLAGS_ANYWHERE;

	err = vm_allocate((vm_map_t)mach_task_self(), (vm_address_t *)&ret,
	    (vm_size_t)size, flags);
	if (err != KERN_SUCCESS)
		ret = NULL;

	assert(ret == NULL || (addr == NULL && ret != addr)
	    || (addr != NULL && ret == addr));
	return (ret);
}

static void
pages_unmap(void *addr, size_t size)
{
	kern_return_t err;

	err = vm_deallocate((vm_map_t)mach_task_self(), (vm_address_t)addr,
	    (vm_size_t)size);
	if (err != KERN_SUCCESS) {
		malloc_message(_getprogname(),
		    ": (malloc) Error in vm_deallocate(): ",
		    mach_error_string(err), "\n");
		if (opt_abort)
			abort();
	}
}

#define	VM_COPY_MIN (pagesize << 5)
static inline void
pages_copy(void *dest, const void *src, size_t n)
{

	assert((void *)((uintptr_t)dest & ~pagesize_mask) == dest);
	assert(n >= VM_COPY_MIN);
	assert((void *)((uintptr_t)src & ~pagesize_mask) == src);

	vm_copy(mach_task_self(), (vm_address_t)src, (vm_size_t)n,
	    (vm_address_t)dest);
}
#else /* MOZ_MEMORY_DARWIN */
#ifdef JEMALLOC_USES_MAP_ALIGN
static void *
pages_map_align(size_t size, int pfd, size_t alignment)
{
	void *ret;

	/*
	 * We don't use MAP_FIXED here, because it can cause the *replacement*
	 * of existing mappings, and we only want to create new mappings.
	 */
#ifdef MALLOC_PAGEFILE
	if (pfd != -1) {
		ret = mmap((void *)alignment, size, PROT_READ | PROT_WRITE, MAP_PRIVATE |
		    MAP_NOSYNC | MAP_ALIGN, pfd, 0);
	} else
#endif
	       {
		ret = mmap((void *)alignment, size, PROT_READ | PROT_WRITE, MAP_PRIVATE |
		    MAP_NOSYNC | MAP_ALIGN | MAP_ANON, -1, 0);
	}
	assert(ret != NULL);

	if (ret == MAP_FAILED)
		ret = NULL;
	return (ret);
}
#endif

static void *
pages_map(void *addr, size_t size, int pfd)
{
	void *ret;

	/*
	 * We don't use MAP_FIXED here, because it can cause the *replacement*
	 * of existing mappings, and we only want to create new mappings.
	 */
#ifdef MALLOC_PAGEFILE
	if (pfd != -1) {
		ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE |
		    MAP_NOSYNC, pfd, 0);
	} else
#endif
	       {
		ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE |
		    MAP_ANON, -1, 0);
	}
	assert(ret != NULL);

	if (ret == MAP_FAILED)
		ret = NULL;
	else if (addr != NULL && ret != addr) {
		/*
		 * We succeeded in mapping memory, but not in the right place.
		 */
		if (munmap(ret, size) == -1) {
			char buf[STRERROR_BUF];

			strerror_r(errno, buf, sizeof(buf));
			_malloc_message(_getprogname(),
			    ": (malloc) Error in munmap(): ", buf, "\n");
			if (opt_abort)
				abort();
		}
		ret = NULL;
	}

	assert(ret == NULL || (addr == NULL && ret != addr)
	    || (addr != NULL && ret == addr));
	return (ret);
}

static void
pages_unmap(void *addr, size_t size)
{

	if (munmap(addr, size) == -1) {
		char buf[STRERROR_BUF];

		strerror_r(errno, buf, sizeof(buf));
		_malloc_message(_getprogname(),
		    ": (malloc) Error in munmap(): ", buf, "\n");
		if (opt_abort)
			abort();
	}
}
#endif

#ifdef MALLOC_VALIDATE
static inline malloc_rtree_t *
malloc_rtree_new(unsigned bits)
{
	malloc_rtree_t *ret;
	unsigned bits_per_level, height, i;

	bits_per_level = ffs(pow2_ceil((MALLOC_RTREE_NODESIZE /
	    sizeof(void *)))) - 1;
	height = bits / bits_per_level;
	if (height * bits_per_level != bits)
		height++;
	assert(height * bits_per_level >= bits);

	ret = (malloc_rtree_t*)base_calloc(1, sizeof(malloc_rtree_t) + (sizeof(unsigned) *
	    (height - 1)));
	if (ret == NULL)
		return (NULL);

	malloc_spin_init(&ret->lock);
	ret->height = height;
	if (bits_per_level * height > bits)
		ret->level2bits[0] = bits % bits_per_level;
	else
		ret->level2bits[0] = bits_per_level;
	for (i = 1; i < height; i++)
		ret->level2bits[i] = bits_per_level;

	ret->root = (void**)base_calloc(1, sizeof(void *) << ret->level2bits[0]);
	if (ret->root == NULL) {
		/*
		 * We leak the rtree here, since there's no generic base
		 * deallocation.
		 */
		return (NULL);
	}

	return (ret);
}

/* The least significant bits of the key are ignored. */
static inline void *
malloc_rtree_get(malloc_rtree_t *rtree, uintptr_t key)
{
	void *ret;
	uintptr_t subkey;
	unsigned i, lshift, height, bits;
	void **node, **child;

	malloc_spin_lock(&rtree->lock);
	for (i = lshift = 0, height = rtree->height, node = rtree->root;
	    i < height - 1;
	    i++, lshift += bits, node = child) {
		bits = rtree->level2bits[i];
		subkey = (key << lshift) >> ((SIZEOF_PTR << 3) - bits);
		child = (void**)node[subkey];
		if (child == NULL) {
			malloc_spin_unlock(&rtree->lock);
			return (NULL);
		}
	}

	/* node is a leaf, so it contains values rather than node pointers. */
	bits = rtree->level2bits[i];
	subkey = (key << lshift) >> ((SIZEOF_PTR << 3) - bits);
	ret = node[subkey];
	malloc_spin_unlock(&rtree->lock);

	return (ret);
}

static inline bool
malloc_rtree_set(malloc_rtree_t *rtree, uintptr_t key, void *val)
{
	uintptr_t subkey;
	unsigned i, lshift, height, bits;
	void **node, **child;

	malloc_spin_lock(&rtree->lock);
	for (i = lshift = 0, height = rtree->height, node = rtree->root;
	    i < height - 1;
	    i++, lshift += bits, node = child) {
		bits = rtree->level2bits[i];
		subkey = (key << lshift) >> ((SIZEOF_PTR << 3) - bits);
		child = (void**)node[subkey];
		if (child == NULL) {
			child = (void**)base_calloc(1, sizeof(void *) <<
			    rtree->level2bits[i+1]);
			if (child == NULL) {
				malloc_spin_unlock(&rtree->lock);
				return (true);
			}
			node[subkey] = child;
		}
	}

	/* node is a leaf, so it contains values rather than node pointers. */
	bits = rtree->level2bits[i];
	subkey = (key << lshift) >> ((SIZEOF_PTR << 3) - bits);
	node[subkey] = val;
	malloc_spin_unlock(&rtree->lock);

	return (false);
}
#endif

static void *
chunk_alloc_mmap(size_t size, bool pagefile)
{
	void *ret;
#ifndef JEMALLOC_USES_MAP_ALIGN
	size_t offset;
#endif
	int pfd;

#ifdef MALLOC_PAGEFILE
	if (opt_pagefile && pagefile) {
		pfd = pagefile_init(size);
		if (pfd == -1)
			return (NULL);
	} else
#endif
		pfd = -1;

	/*
	 * Windows requires that there be a 1:1 mapping between VM
	 * allocation/deallocation operations.  Therefore, take care here to
	 * acquire the final result via one mapping operation.  This means
	 * unmapping any preliminary result that is not correctly aligned.
	 *
	 * The MALLOC_PAGEFILE code also benefits from this mapping algorithm,
	 * since it reduces the number of page files.
	 */

#ifdef JEMALLOC_USES_MAP_ALIGN
	ret = pages_map_align(size, pfd, chunksize);
#else
	ret = pages_map(NULL, size, pfd);
	if (ret == NULL)
		goto RETURN;

	offset = CHUNK_ADDR2OFFSET(ret);
	if (offset != 0) {
		/* Deallocate, then try to allocate at (ret + size - offset). */
		pages_unmap(ret, size);
		ret = pages_map((void *)((uintptr_t)ret + size - offset), size,
		    pfd);
		while (ret == NULL) {
			/*
			 * Over-allocate in order to map a memory region that
			 * is definitely large enough.
			 */
			ret = pages_map(NULL, size + chunksize, -1);
			if (ret == NULL)
				goto RETURN;
			/*
			 * Deallocate, then allocate the correct size, within
			 * the over-sized mapping.
			 */
			offset = CHUNK_ADDR2OFFSET(ret);
			pages_unmap(ret, size + chunksize);
			if (offset == 0)
				ret = pages_map(ret, size, pfd);
			else {
				ret = pages_map((void *)((uintptr_t)ret +
				    chunksize - offset), size, pfd);
			}
			/*
			 * Failure here indicates a race with another thread, so
			 * try again.
			 */
		}
	}
RETURN:
#endif
#ifdef MALLOC_PAGEFILE
	if (pfd != -1)
		pagefile_close(pfd);
#endif
#ifdef MALLOC_STATS
	if (ret != NULL)
		stats_chunks.nchunks += (size / chunksize);
#endif
	return (ret);
}

#ifdef MALLOC_PAGEFILE
static int
pagefile_init(size_t size)
{
	int ret;
	size_t i;
	char pagefile_path[PATH_MAX];
	char zbuf[MALLOC_PAGEFILE_WRITE_SIZE];

	/*
	 * Create a temporary file, then immediately unlink it so that it will
	 * not persist.
	 */
	strcpy(pagefile_path, pagefile_templ);
	ret = mkstemp(pagefile_path);
	if (ret == -1)
		return (ret);
	if (unlink(pagefile_path)) {
		char buf[STRERROR_BUF];

		strerror_r(errno, buf, sizeof(buf));
		_malloc_message(_getprogname(), ": (malloc) Error in unlink(\"",
		    pagefile_path, "\"):");
		_malloc_message(buf, "\n", "", "");
		if (opt_abort)
			abort();
	}

	/*
	 * Write sequential zeroes to the file in order to assure that disk
	 * space is committed, with minimal fragmentation.  It would be
	 * sufficient to write one zero per disk block, but that potentially
	 * results in more system calls, for no real gain.
	 */
	memset(zbuf, 0, sizeof(zbuf));
	for (i = 0; i < size; i += sizeof(zbuf)) {
		if (write(ret, zbuf, sizeof(zbuf)) != sizeof(zbuf)) {
			if (errno != ENOSPC) {
				char buf[STRERROR_BUF];

				strerror_r(errno, buf, sizeof(buf));
				_malloc_message(_getprogname(),
				    ": (malloc) Error in write(): ", buf, "\n");
				if (opt_abort)
					abort();
			}
			pagefile_close(ret);
			return (-1);
		}
	}

	return (ret);
}

static void
pagefile_close(int pfd)
{

	if (close(pfd)) {
		char buf[STRERROR_BUF];

		strerror_r(errno, buf, sizeof(buf));
		_malloc_message(_getprogname(),
		    ": (malloc) Error in close(): ", buf, "\n");
		if (opt_abort)
			abort();
	}
}
#endif

static void *
chunk_alloc(size_t size, bool zero, bool pagefile)
{
	void *ret;

	assert(size != 0);
	assert((size & chunksize_mask) == 0);

	ret = chunk_alloc_mmap(size, pagefile);
	if (ret != NULL) {
		goto RETURN;
	}

	/* All strategies for allocation failed. */
	ret = NULL;
RETURN:
#ifdef MALLOC_STATS
	if (ret != NULL)
		stats_chunks.curchunks += (size / chunksize);
	if (stats_chunks.curchunks > stats_chunks.highchunks)
		stats_chunks.highchunks = stats_chunks.curchunks;
#endif

#ifdef MALLOC_VALIDATE
	if (ret != NULL) {
		if (malloc_rtree_set(chunk_rtree, (uintptr_t)ret, ret)) {
			chunk_dealloc(ret, size);
			return (NULL);
		}
	}
#endif

	assert(CHUNK_ADDR2BASE(ret) == ret);
	return (ret);
}

static void
chunk_dealloc_mmap(void *chunk, size_t size)
{

	pages_unmap(chunk, size);
}

static void
chunk_dealloc(void *chunk, size_t size)
{

	assert(chunk != NULL);
	assert(CHUNK_ADDR2BASE(chunk) == chunk);
	assert(size != 0);
	assert((size & chunksize_mask) == 0);

#ifdef MALLOC_STATS
	stats_chunks.curchunks -= (size / chunksize);
#endif
#ifdef MALLOC_VALIDATE
	malloc_rtree_set(chunk_rtree, (uintptr_t)chunk, NULL);
#endif

	chunk_dealloc_mmap(chunk, size);
}

/*
 * End chunk management functions.
 */
/******************************************************************************/
/*
 * Begin arena.
 */

/*
 * Choose an arena based on a per-thread value (fast-path code, calls slow-path
 * code if necessary).
 */
static inline arena_t *
choose_arena(void)
{
	arena_t *ret;

	/*
	 * We can only use TLS if this is a PIC library, since for the static
	 * library version, libc's malloc is used by TLS allocation, which
	 * introduces a bootstrapping issue.
	 */
#ifndef NO_TLS
	if (__isthreaded == false) {
	    /* Avoid the overhead of TLS for single-threaded operation. */
	    return (arenas[0]);
	}

#  ifdef MOZ_MEMORY_WINDOWS
	ret = (arena_t*)TlsGetValue(tlsIndex);
#  else
	ret = arenas_map;
#  endif

	if (ret == NULL) {
		ret = choose_arena_hard();
		assert(ret != NULL);
	}
#else
	if (__isthreaded && narenas > 1) {
		unsigned long ind;

		/*
		 * Hash _pthread_self() to one of the arenas.  There is a prime
		 * number of arenas, so this has a reasonable chance of
		 * working.  Even so, the hashing can be easily thwarted by
		 * inconvenient _pthread_self() values.  Without specific
		 * knowledge of how _pthread_self() calculates values, we can't
		 * easily do much better than this.
		 */
		ind = (unsigned long) _pthread_self() % narenas;

		/*
		 * Optimistially assume that arenas[ind] has been initialized.
		 * At worst, we find out that some other thread has already
		 * done so, after acquiring the lock in preparation.  Note that
		 * this lazy locking also has the effect of lazily forcing
		 * cache coherency; without the lock acquisition, there's no
		 * guarantee that modification of arenas[ind] by another thread
		 * would be seen on this CPU for an arbitrary amount of time.
		 *
		 * In general, this approach to modifying a synchronized value
		 * isn't a good idea, but in this case we only ever modify the
		 * value once, so things work out well.
		 */
		ret = arenas[ind];
		if (ret == NULL) {
			/*
			 * Avoid races with another thread that may have already
			 * initialized arenas[ind].
			 */
			malloc_spin_lock(&arenas_lock);
			if (arenas[ind] == NULL)
				ret = arenas_extend((unsigned)ind);
			else
				ret = arenas[ind];
			malloc_spin_unlock(&arenas_lock);
		}
	} else
		ret = arenas[0];
#endif

	assert(ret != NULL);
	return (ret);
}

#ifndef NO_TLS
/*
 * Choose an arena based on a per-thread value (slow-path code only, called
 * only by choose_arena()).
 */
static arena_t *
choose_arena_hard(void)
{
	arena_t *ret;

	assert(__isthreaded);

#ifdef MALLOC_BALANCE
	/* Seed the PRNG used for arena load balancing. */
	SPRN(balance, (uint32_t)(uintptr_t)(_pthread_self()));
#endif

	if (narenas > 1) {
#ifdef MALLOC_BALANCE
		unsigned ind;

		ind = PRN(balance, narenas_2pow);
		if ((ret = arenas[ind]) == NULL) {
			malloc_spin_lock(&arenas_lock);
			if ((ret = arenas[ind]) == NULL)
				ret = arenas_extend(ind);
			malloc_spin_unlock(&arenas_lock);
		}
#else
		malloc_spin_lock(&arenas_lock);
		if ((ret = arenas[next_arena]) == NULL)
			ret = arenas_extend(next_arena);
		next_arena = (next_arena + 1) % narenas;
		malloc_spin_unlock(&arenas_lock);
#endif
	} else
		ret = arenas[0];

#ifdef MOZ_MEMORY_WINDOWS
	TlsSetValue(tlsIndex, ret);
#else
	arenas_map = ret;
#endif

	return (ret);
}
#endif

static inline int
arena_chunk_comp(arena_chunk_t *a, arena_chunk_t *b)
{
	uintptr_t a_chunk = (uintptr_t)a;
	uintptr_t b_chunk = (uintptr_t)b;

	assert(a != NULL);
	assert(b != NULL);

	return ((a_chunk > b_chunk) - (a_chunk < b_chunk));
}

/* Wrap red-black tree macros in functions. */
rb_wrap(static, arena_chunk_tree_dirty_, arena_chunk_tree_t,
    arena_chunk_t, link_dirty, arena_chunk_comp)

static inline int
arena_run_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
{
	uintptr_t a_mapelm = (uintptr_t)a;
	uintptr_t b_mapelm = (uintptr_t)b;

	assert(a != NULL);
	assert(b != NULL);

	return ((a_mapelm > b_mapelm) - (a_mapelm < b_mapelm));
}

/* Wrap red-black tree macros in functions. */
rb_wrap(static, arena_run_tree_, arena_run_tree_t, arena_chunk_map_t, link,
    arena_run_comp)

static inline int
arena_avail_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
{
	int ret;
	size_t a_size = a->bits & ~pagesize_mask;
	size_t b_size = b->bits & ~pagesize_mask;

	ret = (a_size > b_size) - (a_size < b_size);
	if (ret == 0) {
		uintptr_t a_mapelm, b_mapelm;

		if ((a->bits & CHUNK_MAP_KEY) == 0)
			a_mapelm = (uintptr_t)a;
		else {
			/*
			 * Treat keys as though they are lower than anything
			 * else.
			 */
			a_mapelm = 0;
		}
		b_mapelm = (uintptr_t)b;

		ret = (a_mapelm > b_mapelm) - (a_mapelm < b_mapelm);
	}

	return (ret);
}

/* Wrap red-black tree macros in functions. */
rb_wrap(static, arena_avail_tree_, arena_avail_tree_t, arena_chunk_map_t, link,
    arena_avail_comp)

static inline void *
arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin)
{
	void *ret;
	unsigned i, mask, bit, regind;

	assert(run->magic == ARENA_RUN_MAGIC);
	assert(run->regs_minelm < bin->regs_mask_nelms);

	/*
	 * Move the first check outside the loop, so that run->regs_minelm can
	 * be updated unconditionally, without the possibility of updating it
	 * multiple times.
	 */
	i = run->regs_minelm;
	mask = run->regs_mask[i];
	if (mask != 0) {
		/* Usable allocation found. */
		bit = ffs((int)mask) - 1;

		regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
		assert(regind < bin->nregs);
		ret = (void *)(((uintptr_t)run) + bin->reg0_offset
		    + (bin->reg_size * regind));

		/* Clear bit. */
		mask ^= (1U << bit);
		run->regs_mask[i] = mask;

		return (ret);
	}

	for (i++; i < bin->regs_mask_nelms; i++) {
		mask = run->regs_mask[i];
		if (mask != 0) {
			/* Usable allocation found. */
			bit = ffs((int)mask) - 1;

			regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
			assert(regind < bin->nregs);
			ret = (void *)(((uintptr_t)run) + bin->reg0_offset
			    + (bin->reg_size * regind));

			/* Clear bit. */
			mask ^= (1U << bit);
			run->regs_mask[i] = mask;

			/*
			 * Make a note that nothing before this element
			 * contains a free region.
			 */
			run->regs_minelm = i; /* Low payoff: + (mask == 0); */

			return (ret);
		}
	}
	/* Not reached. */
	assert(0);
	return (NULL);
}

static inline void
arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size)
{
	/*
	 * To divide by a number D that is not a power of two we multiply
	 * by (2^21 / D) and then right shift by 21 positions.
	 *
	 *   X / D
	 *
	 * becomes
	 *
	 *   (X * size_invs[(D >> QUANTUM_2POW_MIN) - 3]) >> SIZE_INV_SHIFT
	 */
#define	SIZE_INV_SHIFT 21
#define	SIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << QUANTUM_2POW_MIN)) + 1)
	static const unsigned size_invs[] = {
	    SIZE_INV(3),
	    SIZE_INV(4), SIZE_INV(5), SIZE_INV(6), SIZE_INV(7),
	    SIZE_INV(8), SIZE_INV(9), SIZE_INV(10), SIZE_INV(11),
	    SIZE_INV(12),SIZE_INV(13), SIZE_INV(14), SIZE_INV(15),
	    SIZE_INV(16),SIZE_INV(17), SIZE_INV(18), SIZE_INV(19),
	    SIZE_INV(20),SIZE_INV(21), SIZE_INV(22), SIZE_INV(23),
	    SIZE_INV(24),SIZE_INV(25), SIZE_INV(26), SIZE_INV(27),
	    SIZE_INV(28),SIZE_INV(29), SIZE_INV(30), SIZE_INV(31)
#if (QUANTUM_2POW_MIN < 4)
	    ,
	    SIZE_INV(32), SIZE_INV(33), SIZE_INV(34), SIZE_INV(35),
	    SIZE_INV(36), SIZE_INV(37), SIZE_INV(38), SIZE_INV(39),
	    SIZE_INV(40), SIZE_INV(41), SIZE_INV(42), SIZE_INV(43),
	    SIZE_INV(44), SIZE_INV(45), SIZE_INV(46), SIZE_INV(47),
	    SIZE_INV(48), SIZE_INV(49), SIZE_INV(50), SIZE_INV(51),
	    SIZE_INV(52), SIZE_INV(53), SIZE_INV(54), SIZE_INV(55),
	    SIZE_INV(56), SIZE_INV(57), SIZE_INV(58), SIZE_INV(59),
	    SIZE_INV(60), SIZE_INV(61), SIZE_INV(62), SIZE_INV(63)
#endif
	};
	unsigned diff, regind, elm, bit;

	assert(run->magic == ARENA_RUN_MAGIC);
	assert(((sizeof(size_invs)) / sizeof(unsigned)) + 3
	    >= (SMALL_MAX_DEFAULT >> QUANTUM_2POW_MIN));

	/*
	 * Avoid doing division with a variable divisor if possible.  Using
	 * actual division here can reduce allocator throughput by over 20%!
	 */
	diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run - bin->reg0_offset);
	if ((size & (size - 1)) == 0) {
		/*
		 * log2_table allows fast division of a power of two in the
		 * [1..128] range.
		 *
		 * (x / divisor) becomes (x >> log2_table[divisor - 1]).
		 */
		static const unsigned char log2_table[] = {
		    0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7
		};

		if (size <= 128)
			regind = (diff >> log2_table[size - 1]);
		else if (size <= 32768)
			regind = diff >> (8 + log2_table[(size >> 8) - 1]);
		else {
			/*
			 * The run size is too large for us to use the lookup
			 * table.  Use real division.
			 */
			regind = diff / size;
		}
	} else if (size <= ((sizeof(size_invs) / sizeof(unsigned))
	    << QUANTUM_2POW_MIN) + 2) {
		regind = size_invs[(size >> QUANTUM_2POW_MIN) - 3] * diff;
		regind >>= SIZE_INV_SHIFT;
	} else {
		/*
		 * size_invs isn't large enough to handle this size class, so
		 * calculate regind using actual division.  This only happens
		 * if the user increases small_max via the 'S' runtime
		 * configuration option.
		 */
		regind = diff / size;
	};
	assert(diff == regind * size);
	assert(regind < bin->nregs);

	elm = regind >> (SIZEOF_INT_2POW + 3);
	if (elm < run->regs_minelm)
		run->regs_minelm = elm;
	bit = regind - (elm << (SIZEOF_INT_2POW + 3));
	assert((run->regs_mask[elm] & (1U << bit)) == 0);
	run->regs_mask[elm] |= (1U << bit);
#undef SIZE_INV
#undef SIZE_INV_SHIFT
}

static void
arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
    bool zero)
{
	arena_chunk_t *chunk;
	size_t old_ndirty, run_ind, total_pages, need_pages, rem_pages, i;

	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
	old_ndirty = chunk->ndirty;
	run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
	    >> pagesize_2pow);
	total_pages = (chunk->map[run_ind].bits & ~pagesize_mask) >>
	    pagesize_2pow;
	need_pages = (size >> pagesize_2pow);
	assert(need_pages > 0);
	assert(need_pages <= total_pages);
	rem_pages = total_pages - need_pages;

	arena_avail_tree_remove(&arena->runs_avail, &chunk->map[run_ind]);

	/* Keep track of trailing unused pages for later use. */
	if (rem_pages > 0) {
		chunk->map[run_ind+need_pages].bits = (rem_pages <<
		    pagesize_2pow) | (chunk->map[run_ind+need_pages].bits &
		    pagesize_mask);
		chunk->map[run_ind+total_pages-1].bits = (rem_pages <<
		    pagesize_2pow) | (chunk->map[run_ind+total_pages-1].bits &
		    pagesize_mask);
		arena_avail_tree_insert(&arena->runs_avail,
		    &chunk->map[run_ind+need_pages]);
	}

	for (i = 0; i < need_pages; i++) {
#ifdef MALLOC_DECOMMIT
		/*
		 * Commit decommitted pages if necessary.  If a decommitted
		 * page is encountered, commit all needed adjacent decommitted
		 * pages in one operation, in order to reduce system call
		 * overhead.
		 */
		if (chunk->map[run_ind + i].bits & CHUNK_MAP_DECOMMITTED) {
			size_t j;

			/*
			 * Advance i+j to just past the index of the last page
			 * to commit.  Clear CHUNK_MAP_DECOMMITTED along the
			 * way.
			 */
			for (j = 0; i + j < need_pages && (chunk->map[run_ind +
			    i + j].bits & CHUNK_MAP_DECOMMITTED); j++) {
				chunk->map[run_ind + i + j].bits ^=
				    CHUNK_MAP_DECOMMITTED;
			}

			pages_commit((void *)((uintptr_t)chunk + ((run_ind + i)
			    << pagesize_2pow)), (j << pagesize_2pow));
#  ifdef MALLOC_STATS
			arena->stats.ncommit++;
			arena->stats.committed += j;
#  endif
		} else /* No need to zero since commit zeros. */
#endif

		/* Zero if necessary. */
		if (zero) {
			if ((chunk->map[run_ind + i].bits & CHUNK_MAP_ZEROED)
			    == 0) {
				VALGRIND_MALLOCLIKE_BLOCK((void *)((uintptr_t)
				    chunk + ((run_ind + i) << pagesize_2pow)),
				    pagesize, 0, false);
				memset((void *)((uintptr_t)chunk + ((run_ind
				    + i) << pagesize_2pow)), 0, pagesize);
				VALGRIND_FREELIKE_BLOCK((void *)((uintptr_t)
				    chunk + ((run_ind + i) << pagesize_2pow)),
				    0);
				/* CHUNK_MAP_ZEROED is cleared below. */
			}
		}

		/* Update dirty page accounting. */
		if (chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY) {
			chunk->ndirty--;
			arena->ndirty--;
			/* CHUNK_MAP_DIRTY is cleared below. */
		}

		/* Initialize the chunk map. */
		if (large) {
			chunk->map[run_ind + i].bits = CHUNK_MAP_LARGE
			    | CHUNK_MAP_ALLOCATED;
		} else {
			chunk->map[run_ind + i].bits = (size_t)run
			    | CHUNK_MAP_ALLOCATED;
		}
	}

	/*
	 * Set the run size only in the first element for large runs.  This is
	 * primarily a debugging aid, since the lack of size info for trailing
	 * pages only matters if the application tries to operate on an
	 * interior pointer.
	 */
	if (large)
		chunk->map[run_ind].bits |= size;

	if (chunk->ndirty == 0 && old_ndirty > 0)
		arena_chunk_tree_dirty_remove(&arena->chunks_dirty, chunk);
}

static void
arena_chunk_init(arena_t *arena, arena_chunk_t *chunk)
{
	arena_run_t *run;
	size_t i;

	VALGRIND_MALLOCLIKE_BLOCK(chunk, (arena_chunk_header_npages <<
	    pagesize_2pow), 0, false);
#ifdef MALLOC_STATS
	arena->stats.mapped += chunksize;
#endif

	chunk->arena = arena;

	/*
	 * Claim that no pages are in use, since the header is merely overhead.
	 */
	chunk->ndirty = 0;

	/* Initialize the map to contain one maximal free untouched run. */
	run = (arena_run_t *)((uintptr_t)chunk + (arena_chunk_header_npages <<
	    pagesize_2pow));
	for (i = 0; i < arena_chunk_header_npages; i++)
		chunk->map[i].bits = 0;
	chunk->map[i].bits = arena_maxclass
#ifdef MALLOC_DECOMMIT
	    | CHUNK_MAP_DECOMMITTED
#endif
	    | CHUNK_MAP_ZEROED;
	for (i++; i < chunk_npages-1; i++) {
		chunk->map[i].bits =
#ifdef MALLOC_DECOMMIT
		    CHUNK_MAP_DECOMMITTED |
#endif
		    CHUNK_MAP_ZEROED;
	}
	chunk->map[chunk_npages-1].bits = arena_maxclass
#ifdef MALLOC_DECOMMIT
	    | CHUNK_MAP_DECOMMITTED
#endif
	    | CHUNK_MAP_ZEROED;

#ifdef MALLOC_DECOMMIT
	/*
	 * Start out decommitted, in order to force a closer correspondence
	 * between dirty pages and committed untouched pages.
	 */
	pages_decommit(run, arena_maxclass);
#  ifdef MALLOC_STATS
	arena->stats.ndecommit++;
	arena->stats.decommitted += (chunk_npages - arena_chunk_header_npages);
	arena->stats.committed += arena_chunk_header_npages;
#  endif
#endif

	/* Insert the run into the runs_avail tree. */
	arena_avail_tree_insert(&arena->runs_avail,
	    &chunk->map[arena_chunk_header_npages]);
}

static void
arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
{

	if (arena->spare != NULL) {
		if (arena->spare->ndirty > 0) {
			arena_chunk_tree_dirty_remove(
			    &chunk->arena->chunks_dirty, arena->spare);
			arena->ndirty -= arena->spare->ndirty;
#if (defined(MALLOC_STATS) && defined(MALLOC_DECOMMIT))
			arena->stats.committed -= arena->spare->ndirty;
#endif
		}
		VALGRIND_FREELIKE_BLOCK(arena->spare, 0);
		chunk_dealloc((void *)arena->spare, chunksize);
#ifdef MALLOC_STATS
		arena->stats.mapped -= chunksize;
#  ifdef MALLOC_DECOMMIT
		arena->stats.committed -= arena_chunk_header_npages;
#  endif
#endif
	}

	/*
	 * Remove run from runs_avail, so that the arena does not use it.
	 * Dirty page flushing only uses the chunks_dirty tree, so leaving this
	 * chunk in the chunks_* trees is sufficient for that purpose.
	 */
	arena_avail_tree_remove(&arena->runs_avail,
	    &chunk->map[arena_chunk_header_npages]);

	arena->spare = chunk;
}

static arena_run_t *
arena_run_alloc(arena_t *arena, arena_bin_t *bin, size_t size, bool large,
    bool zero)
{
	arena_run_t *run;
	arena_chunk_map_t *mapelm, key;

	assert(size <= arena_maxclass);
	assert((size & pagesize_mask) == 0);

	/* Search the arena's chunks for the lowest best fit. */
	key.bits = size | CHUNK_MAP_KEY;
	mapelm = arena_avail_tree_nsearch(&arena->runs_avail, &key);
	if (mapelm != NULL) {
		arena_chunk_t *chunk =
		    (arena_chunk_t*)CHUNK_ADDR2BASE(mapelm);
		size_t pageind = ((uintptr_t)mapelm -
		    (uintptr_t)chunk->map) /
		    sizeof(arena_chunk_map_t);

		run = (arena_run_t *)((uintptr_t)chunk + (pageind
		    << pagesize_2pow));
		arena_run_split(arena, run, size, large, zero);
		return (run);
	}

	if (arena->spare != NULL) {
		/* Use the spare. */
		arena_chunk_t *chunk = arena->spare;
		arena->spare = NULL;
		run = (arena_run_t *)((uintptr_t)chunk +
		    (arena_chunk_header_npages << pagesize_2pow));
		/* Insert the run into the runs_avail tree. */
		arena_avail_tree_insert(&arena->runs_avail,
		    &chunk->map[arena_chunk_header_npages]);
		arena_run_split(arena, run, size, large, zero);
		return (run);
	}

	/*
	 * No usable runs.  Create a new chunk from which to allocate
	 * the run.
	 */
	{
		arena_chunk_t *chunk = (arena_chunk_t *)
		    chunk_alloc(chunksize, true, true);
		if (chunk == NULL)
			return (NULL);

		arena_chunk_init(arena, chunk);
		run = (arena_run_t *)((uintptr_t)chunk +
		    (arena_chunk_header_npages << pagesize_2pow));
	}
	/* Update page map. */
	arena_run_split(arena, run, size, large, zero);
	return (run);
}

static void
arena_purge(arena_t *arena)
{
	arena_chunk_t *chunk;
	size_t i, npages;
#ifdef MALLOC_DEBUG
	size_t ndirty = 0;
	rb_foreach_begin(arena_chunk_t, link_dirty, &arena->chunks_dirty,
	    chunk) {
		ndirty += chunk->ndirty;
	} rb_foreach_end(arena_chunk_t, link_dirty, &arena->chunks_dirty, chunk)
	assert(ndirty == arena->ndirty);
#endif
	assert(arena->ndirty > opt_dirty_max);

#ifdef MALLOC_STATS
	arena->stats.npurge++;
#endif

	/*
	 * Iterate downward through chunks until enough dirty memory has been
	 * purged.  Terminate as soon as possible in order to minimize the
	 * number of system calls, even if a chunk has only been partially
	 * purged.
	 */
	while (arena->ndirty > (opt_dirty_max >> 1)) {
		chunk = arena_chunk_tree_dirty_last(&arena->chunks_dirty);
		assert(chunk != NULL);

		for (i = chunk_npages - 1; chunk->ndirty > 0; i--) {
			assert(i >= arena_chunk_header_npages);

			if (chunk->map[i].bits & CHUNK_MAP_DIRTY) {
#ifdef MALLOC_DECOMMIT
				assert((chunk->map[i].bits &
				    CHUNK_MAP_DECOMMITTED) == 0);
#endif
				chunk->map[i].bits ^=
#ifdef MALLOC_DECOMMIT
				    CHUNK_MAP_DECOMMITTED |
#endif
				    CHUNK_MAP_DIRTY;
				/* Find adjacent dirty run(s). */
				for (npages = 1; i > arena_chunk_header_npages
				    && (chunk->map[i - 1].bits &
				    CHUNK_MAP_DIRTY); npages++) {
					i--;
#ifdef MALLOC_DECOMMIT
					assert((chunk->map[i].bits &
					    CHUNK_MAP_DECOMMITTED) == 0);
#endif
					chunk->map[i].bits ^=
#ifdef MALLOC_DECOMMIT
					    CHUNK_MAP_DECOMMITTED |
#endif
					    CHUNK_MAP_DIRTY;
				}
				chunk->ndirty -= npages;
				arena->ndirty -= npages;

#ifdef MALLOC_DECOMMIT
				pages_decommit((void *)((uintptr_t)
				    chunk + (i << pagesize_2pow)),
				    (npages << pagesize_2pow));
#  ifdef MALLOC_STATS
				arena->stats.ndecommit++;
				arena->stats.decommitted += npages;
				arena->stats.committed -= npages;
#  endif
#else
				madvise((void *)((uintptr_t)chunk + (i <<
				    pagesize_2pow)), (npages << pagesize_2pow),
				    MADV_FREE);
#endif
#ifdef MALLOC_STATS
				arena->stats.nmadvise++;
				arena->stats.purged += npages;
#endif
				if (arena->ndirty <= (opt_dirty_max >> 1))
					break;
			}
		}

		if (chunk->ndirty == 0) {
			arena_chunk_tree_dirty_remove(&arena->chunks_dirty,
			    chunk);
		}
	}
}

static void
arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
{
	arena_chunk_t *chunk;
	size_t size, run_ind, run_pages;

	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
	run_ind = (size_t)(((uintptr_t)run - (uintptr_t)chunk)
	    >> pagesize_2pow);
	assert(run_ind >= arena_chunk_header_npages);
	assert(run_ind < chunk_npages);
	if ((chunk->map[run_ind].bits & CHUNK_MAP_LARGE) != 0)
		size = chunk->map[run_ind].bits & ~pagesize_mask;
	else
		size = run->bin->run_size;
	run_pages = (size >> pagesize_2pow);

	/* Mark pages as unallocated in the chunk map. */
	if (dirty) {
		size_t i;

		for (i = 0; i < run_pages; i++) {
			assert((chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY)
			    == 0);
			chunk->map[run_ind + i].bits = CHUNK_MAP_DIRTY;
		}

		if (chunk->ndirty == 0) {
			arena_chunk_tree_dirty_insert(&arena->chunks_dirty,
			    chunk);
		}
		chunk->ndirty += run_pages;
		arena->ndirty += run_pages;
	} else {
		size_t i;

		for (i = 0; i < run_pages; i++) {
			chunk->map[run_ind + i].bits &= ~(CHUNK_MAP_LARGE |
			    CHUNK_MAP_ALLOCATED);
		}
	}
	chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
	    pagesize_mask);
	chunk->map[run_ind+run_pages-1].bits = size |
	    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);

	/* Try to coalesce forward. */
	if (run_ind + run_pages < chunk_npages &&
	    (chunk->map[run_ind+run_pages].bits & CHUNK_MAP_ALLOCATED) == 0) {
		size_t nrun_size = chunk->map[run_ind+run_pages].bits &
		    ~pagesize_mask;

		/*
		 * Remove successor from runs_avail; the coalesced run is
		 * inserted later.
		 */
		arena_avail_tree_remove(&arena->runs_avail,
		    &chunk->map[run_ind+run_pages]);

		size += nrun_size;
		run_pages = size >> pagesize_2pow;

		assert((chunk->map[run_ind+run_pages-1].bits & ~pagesize_mask)
		    == nrun_size);
		chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
		    pagesize_mask);
		chunk->map[run_ind+run_pages-1].bits = size |
		    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
	}

	/* Try to coalesce backward. */
	if (run_ind > arena_chunk_header_npages && (chunk->map[run_ind-1].bits &
	    CHUNK_MAP_ALLOCATED) == 0) {
		size_t prun_size = chunk->map[run_ind-1].bits & ~pagesize_mask;

		run_ind -= prun_size >> pagesize_2pow;

		/*
		 * Remove predecessor from runs_avail; the coalesced run is
		 * inserted later.
		 */
		arena_avail_tree_remove(&arena->runs_avail,
		    &chunk->map[run_ind]);

		size += prun_size;
		run_pages = size >> pagesize_2pow;

		assert((chunk->map[run_ind].bits & ~pagesize_mask) ==
		    prun_size);
		chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
		    pagesize_mask);
		chunk->map[run_ind+run_pages-1].bits = size |
		    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
	}

	/* Insert into runs_avail, now that coalescing is complete. */
	arena_avail_tree_insert(&arena->runs_avail, &chunk->map[run_ind]);

	/* Deallocate chunk if it is now completely unused. */
	if ((chunk->map[arena_chunk_header_npages].bits & (~pagesize_mask |
	    CHUNK_MAP_ALLOCATED)) == arena_maxclass)
		arena_chunk_dealloc(arena, chunk);

	/* Enforce opt_dirty_max. */
	if (arena->ndirty > opt_dirty_max)
		arena_purge(arena);
}

static void
arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
    size_t oldsize, size_t newsize)
{
	size_t pageind = ((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow;
	size_t head_npages = (oldsize - newsize) >> pagesize_2pow;

	assert(oldsize > newsize);

	/*
	 * Update the chunk map so that arena_run_dalloc() can treat the
	 * leading run as separately allocated.
	 */
	chunk->map[pageind].bits = (oldsize - newsize) | CHUNK_MAP_LARGE |
	    CHUNK_MAP_ALLOCATED;
	chunk->map[pageind+head_npages].bits = newsize | CHUNK_MAP_LARGE |
	    CHUNK_MAP_ALLOCATED;

	arena_run_dalloc(arena, run, false);
}

static void
arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
    size_t oldsize, size_t newsize, bool dirty)
{
	size_t pageind = ((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow;
	size_t npages = newsize >> pagesize_2pow;

	assert(oldsize > newsize);

	/*
	 * Update the chunk map so that arena_run_dalloc() can treat the
	 * trailing run as separately allocated.
	 */
	chunk->map[pageind].bits = newsize | CHUNK_MAP_LARGE |
	    CHUNK_MAP_ALLOCATED;
	chunk->map[pageind+npages].bits = (oldsize - newsize) | CHUNK_MAP_LARGE
	    | CHUNK_MAP_ALLOCATED;

	arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)run + newsize),
	    dirty);
}

static arena_run_t *
arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin)
{
	arena_chunk_map_t *mapelm;
	arena_run_t *run;
	unsigned i, remainder;

	/* Look for a usable run. */
	mapelm = arena_run_tree_first(&bin->runs);
	if (mapelm != NULL) {
		/* run is guaranteed to have available space. */
		arena_run_tree_remove(&bin->runs, mapelm);
		run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
#ifdef MALLOC_STATS
		bin->stats.reruns++;
#endif
		return (run);
	}
	/* No existing runs have any space available. */

	/* Allocate a new run. */
	run = arena_run_alloc(arena, bin, bin->run_size, false, false);
	if (run == NULL)
		return (NULL);
	/*
	 * Don't initialize if a race in arena_run_alloc() allowed an existing
	 * run to become usable.
	 */
	if (run == bin->runcur)
		return (run);

	VALGRIND_MALLOCLIKE_BLOCK(run, sizeof(arena_run_t) + (sizeof(unsigned) *
	    (bin->regs_mask_nelms - 1)), 0, false);

	/* Initialize run internals. */
	run->bin = bin;

	for (i = 0; i < bin->regs_mask_nelms - 1; i++)
		run->regs_mask[i] = UINT_MAX;
	remainder = bin->nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1);
	if (remainder == 0)
		run->regs_mask[i] = UINT_MAX;
	else {
		/* The last element has spare bits that need to be unset. */
		run->regs_mask[i] = (UINT_MAX >> ((1U << (SIZEOF_INT_2POW + 3))
		    - remainder));
	}

	run->regs_minelm = 0;

	run->nfree = bin->nregs;
#ifdef MALLOC_DEBUG
	run->magic = ARENA_RUN_MAGIC;
#endif

#ifdef MALLOC_STATS
	bin->stats.nruns++;
	bin->stats.curruns++;
	if (bin->stats.curruns > bin->stats.highruns)
		bin->stats.highruns = bin->stats.curruns;
#endif
	return (run);
}

/* bin->runcur must have space available before this function is called. */
static inline void *
arena_bin_malloc_easy(arena_t *arena, arena_bin_t *bin, arena_run_t *run)
{
	void *ret;

	assert(run->magic == ARENA_RUN_MAGIC);
	assert(run->nfree > 0);

	ret = arena_run_reg_alloc(run, bin);
	assert(ret != NULL);
	run->nfree--;

	return (ret);
}

/* Re-fill bin->runcur, then call arena_bin_malloc_easy(). */
static void *
arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin)
{

	bin->runcur = arena_bin_nonfull_run_get(arena, bin);
	if (bin->runcur == NULL)
		return (NULL);
	assert(bin->runcur->magic == ARENA_RUN_MAGIC);
	assert(bin->runcur->nfree > 0);

	return (arena_bin_malloc_easy(arena, bin, bin->runcur));
}

/*
 * Calculate bin->run_size such that it meets the following constraints:
 *
 *   *) bin->run_size >= min_run_size
 *   *) bin->run_size <= arena_maxclass
 *   *) bin->run_size <= RUN_MAX_SMALL
 *   *) run header overhead <= RUN_MAX_OVRHD (or header overhead relaxed).
 *
 * bin->nregs, bin->regs_mask_nelms, and bin->reg0_offset are
 * also calculated here, since these settings are all interdependent.
 */
static size_t
arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size)
{
	size_t try_run_size, good_run_size;
	unsigned good_nregs, good_mask_nelms, good_reg0_offset;
	unsigned try_nregs, try_mask_nelms, try_reg0_offset;

	assert(min_run_size >= pagesize);
	assert(min_run_size <= arena_maxclass);
	assert(min_run_size <= RUN_MAX_SMALL);

	/*
	 * Calculate known-valid settings before entering the run_size
	 * expansion loop, so that the first part of the loop always copies
	 * valid settings.
	 *
	 * The do..while loop iteratively reduces the number of regions until
	 * the run header and the regions no longer overlap.  A closed formula
	 * would be quite messy, since there is an interdependency between the
	 * header's mask length and the number of regions.
	 */
	try_run_size = min_run_size;
	try_nregs = ((try_run_size - sizeof(arena_run_t)) / bin->reg_size)
	    + 1; /* Counter-act try_nregs-- in loop. */
	do {
		try_nregs--;
		try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
		    ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ? 1 : 0);
		try_reg0_offset = try_run_size - (try_nregs * bin->reg_size);
	} while (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1))
	    > try_reg0_offset);

	/* run_size expansion loop. */
	do {
		/*
		 * Copy valid settings before trying more aggressive settings.
		 */
		good_run_size = try_run_size;
		good_nregs = try_nregs;
		good_mask_nelms = try_mask_nelms;
		good_reg0_offset = try_reg0_offset;

		/* Try more aggressive settings. */
		try_run_size += pagesize;
		try_nregs = ((try_run_size - sizeof(arena_run_t)) /
		    bin->reg_size) + 1; /* Counter-act try_nregs-- in loop. */
		do {
			try_nregs--;
			try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
			    ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ?
			    1 : 0);
			try_reg0_offset = try_run_size - (try_nregs *
			    bin->reg_size);
		} while (sizeof(arena_run_t) + (sizeof(unsigned) *
		    (try_mask_nelms - 1)) > try_reg0_offset);
	} while (try_run_size <= arena_maxclass && try_run_size <= RUN_MAX_SMALL
	    && RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX
	    && (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size);

	assert(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1))
	    <= good_reg0_offset);
	assert((good_mask_nelms << (SIZEOF_INT_2POW + 3)) >= good_nregs);

	/* Copy final settings. */
	bin->run_size = good_run_size;
	bin->nregs = good_nregs;
	bin->regs_mask_nelms = good_mask_nelms;
	bin->reg0_offset = good_reg0_offset;

	return (good_run_size);
}

#ifdef MALLOC_BALANCE
static inline void
arena_lock_balance(arena_t *arena)
{
	unsigned contention;

	contention = malloc_spin_lock(&arena->lock);
	if (narenas > 1) {
		/*
		 * Calculate the exponentially averaged contention for this
		 * arena.  Due to integer math always rounding down, this value
		 * decays somewhat faster then normal.
		 */
		arena->contention = (((uint64_t)arena->contention
		    * (uint64_t)((1U << BALANCE_ALPHA_INV_2POW)-1))
		    + (uint64_t)contention) >> BALANCE_ALPHA_INV_2POW;
		if (arena->contention >= opt_balance_threshold)
			arena_lock_balance_hard(arena);
	}
}

static void
arena_lock_balance_hard(arena_t *arena)
{
	uint32_t ind;

	arena->contention = 0;
#ifdef MALLOC_STATS
	arena->stats.nbalance++;
#endif
	ind = PRN(balance, narenas_2pow);
	if (arenas[ind] != NULL) {
#ifdef MOZ_MEMORY_WINDOWS
		TlsSetValue(tlsIndex, arenas[ind]);
#else
		arenas_map = arenas[ind];
#endif
	} else {
		malloc_spin_lock(&arenas_lock);
		if (arenas[ind] != NULL) {
#ifdef MOZ_MEMORY_WINDOWS
			TlsSetValue(tlsIndex, arenas[ind]);
#else
			arenas_map = arenas[ind];
#endif
		} else {
#ifdef MOZ_MEMORY_WINDOWS
			TlsSetValue(tlsIndex, arenas_extend(ind));
#else
			arenas_map = arenas_extend(ind);
#endif
		}
		malloc_spin_unlock(&arenas_lock);
	}
}
#endif

static inline void *
arena_malloc_small(arena_t *arena, size_t size, bool zero)
{
	void *ret;
	arena_bin_t *bin;
	arena_run_t *run;

	if (size < small_min) {
		/* Tiny. */
		size = pow2_ceil(size);
		bin = &arena->bins[ffs((int)(size >> (TINY_MIN_2POW +
		    1)))];
#if (!defined(NDEBUG) || defined(MALLOC_STATS))
		/*
		 * Bin calculation is always correct, but we may need
		 * to fix size for the purposes of assertions and/or
		 * stats accuracy.
		 */
		if (size < (1U << TINY_MIN_2POW))
			size = (1U << TINY_MIN_2POW);
#endif
	} else if (size <= small_max) {
		/* Quantum-spaced. */
		size = QUANTUM_CEILING(size);
		bin = &arena->bins[ntbins + (size >> opt_quantum_2pow)
		    - 1];
	} else {
		/* Sub-page. */
		size = pow2_ceil(size);
		bin = &arena->bins[ntbins + nqbins
		    + (ffs((int)(size >> opt_small_max_2pow)) - 2)];
	}
	assert(size == bin->reg_size);

#ifdef MALLOC_BALANCE
	arena_lock_balance(arena);
#else
	malloc_spin_lock(&arena->lock);
#endif
	if ((run = bin->runcur) != NULL && run->nfree > 0)
		ret = arena_bin_malloc_easy(arena, bin, run);
	else
		ret = arena_bin_malloc_hard(arena, bin);

	if (ret == NULL) {
		malloc_spin_unlock(&arena->lock);
		return (NULL);
	}

#ifdef MALLOC_STATS
	bin->stats.nrequests++;
	arena->stats.nmalloc_small++;
	arena->stats.allocated_small += size;
#endif
	malloc_spin_unlock(&arena->lock);

	VALGRIND_MALLOCLIKE_BLOCK(ret, size, 0, zero);
	if (zero == false) {
#ifdef MALLOC_FILL
		if (opt_junk)
			memset(ret, 0xa5, size);
		else if (opt_zero)
			memset(ret, 0, size);
#endif
	} else
		memset(ret, 0, size);

	return (ret);
}

static void *
arena_malloc_large(arena_t *arena, size_t size, bool zero)
{
	void *ret;

	/* Large allocation. */
	size = PAGE_CEILING(size);
#ifdef MALLOC_BALANCE
	arena_lock_balance(arena);
#else
	malloc_spin_lock(&arena->lock);
#endif
	ret = (void *)arena_run_alloc(arena, NULL, size, true, zero);
	if (ret == NULL) {
		malloc_spin_unlock(&arena->lock);
		return (NULL);
	}
#ifdef MALLOC_STATS
	arena->stats.nmalloc_large++;
	arena->stats.allocated_large += size;
#endif
	malloc_spin_unlock(&arena->lock);

	VALGRIND_MALLOCLIKE_BLOCK(ret, size, 0, zero);
	if (zero == false) {
#ifdef MALLOC_FILL
		if (opt_junk)
			memset(ret, 0xa5, size);
		else if (opt_zero)
			memset(ret, 0, size);
#endif
	}

	return (ret);
}

static inline void *
arena_malloc(arena_t *arena, size_t size, bool zero)
{

	assert(arena != NULL);
	assert(arena->magic == ARENA_MAGIC);
	assert(size != 0);
	assert(QUANTUM_CEILING(size) <= arena_maxclass);

	if (size <= bin_maxclass) {
		return (arena_malloc_small(arena, size, zero));
	} else
		return (arena_malloc_large(arena, size, zero));
}

static inline void *
imalloc(size_t size)
{

	assert(size != 0);

	if (size <= arena_maxclass)
		return (arena_malloc(choose_arena(), size, false));
	else
		return (huge_malloc(size, false));
}

static inline void *
icalloc(size_t size)
{

	if (size <= arena_maxclass)
		return (arena_malloc(choose_arena(), size, true));
	else
		return (huge_malloc(size, true));
}

/* Only handles large allocations that require more than page alignment. */
static void *
arena_palloc(arena_t *arena, size_t alignment, size_t size, size_t alloc_size)
{
	void *ret;
	size_t offset;
	arena_chunk_t *chunk;

	assert((size & pagesize_mask) == 0);
	assert((alignment & pagesize_mask) == 0);

#ifdef MALLOC_BALANCE
	arena_lock_balance(arena);
#else
	malloc_spin_lock(&arena->lock);
#endif
	ret = (void *)arena_run_alloc(arena, NULL, alloc_size, true, false);
	if (ret == NULL) {
		malloc_spin_unlock(&arena->lock);
		return (NULL);
	}

	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ret);

	offset = (uintptr_t)ret & (alignment - 1);
	assert((offset & pagesize_mask) == 0);
	assert(offset < alloc_size);
	if (offset == 0)
		arena_run_trim_tail(arena, chunk, (arena_run_t*)ret, alloc_size, size, false);
	else {
		size_t leadsize, trailsize;

		leadsize = alignment - offset;
		if (leadsize > 0) {
			arena_run_trim_head(arena, chunk, (arena_run_t*)ret, alloc_size,
			    alloc_size - leadsize);
			ret = (void *)((uintptr_t)ret + leadsize);
		}

		trailsize = alloc_size - leadsize - size;
		if (trailsize != 0) {
			/* Trim trailing space. */
			assert(trailsize < alloc_size);
			arena_run_trim_tail(arena, chunk, (arena_run_t*)ret, size + trailsize,
			    size, false);
		}
	}

#ifdef MALLOC_STATS
	arena->stats.nmalloc_large++;
	arena->stats.allocated_large += size;
#endif
	malloc_spin_unlock(&arena->lock);

	VALGRIND_MALLOCLIKE_BLOCK(ret, size, 0, false);
#ifdef MALLOC_FILL
	if (opt_junk)
		memset(ret, 0xa5, size);
	else if (opt_zero)
		memset(ret, 0, size);
#endif
	return (ret);
}

static inline void *
ipalloc(size_t alignment, size_t size)
{
	void *ret;
	size_t ceil_size;

	/*
	 * Round size up to the nearest multiple of alignment.
	 *
	 * This done, we can take advantage of the fact that for each small
	 * size class, every object is aligned at the smallest power of two
	 * that is non-zero in the base two representation of the size.  For
	 * example:
	 *
	 *   Size |   Base 2 | Minimum alignment
	 *   -----+----------+------------------
	 *     96 |  1100000 |  32
	 *    144 | 10100000 |  32
	 *    192 | 11000000 |  64
	 *
	 * Depending on runtime settings, it is possible that arena_malloc()
	 * will further round up to a power of two, but that never causes
	 * correctness issues.
	 */
	ceil_size = (size + (alignment - 1)) & (-alignment);
	/*
	 * (ceil_size < size) protects against the combination of maximal
	 * alignment and size greater than maximal alignment.
	 */
	if (ceil_size < size) {
		/* size_t overflow. */
		return (NULL);
	}

	if (ceil_size <= pagesize || (alignment <= pagesize
	    && ceil_size <= arena_maxclass))
		ret = arena_malloc(choose_arena(), ceil_size, false);
	else {
		size_t run_size;

		/*
		 * We can't achieve sub-page alignment, so round up alignment
		 * permanently; it makes later calculations simpler.
		 */
		alignment = PAGE_CEILING(alignment);
		ceil_size = PAGE_CEILING(size);
		/*
		 * (ceil_size < size) protects against very large sizes within
		 * pagesize of SIZE_T_MAX.
		 *
		 * (ceil_size + alignment < ceil_size) protects against the
		 * combination of maximal alignment and ceil_size large enough
		 * to cause overflow.  This is similar to the first overflow
		 * check above, but it needs to be repeated due to the new
		 * ceil_size value, which may now be *equal* to maximal
		 * alignment, whereas before we only detected overflow if the
		 * original size was *greater* than maximal alignment.
		 */
		if (ceil_size < size || ceil_size + alignment < ceil_size) {
			/* size_t overflow. */
			return (NULL);
		}

		/*
		 * Calculate the size of the over-size run that arena_palloc()
		 * would need to allocate in order to guarantee the alignment.
		 */
		if (ceil_size >= alignment)
			run_size = ceil_size + alignment - pagesize;
		else {
			/*
			 * It is possible that (alignment << 1) will cause
			 * overflow, but it doesn't matter because we also
			 * subtract pagesize, which in the case of overflow
			 * leaves us with a very large run_size.  That causes
			 * the first conditional below to fail, which means
			 * that the bogus run_size value never gets used for
			 * anything important.
			 */
			run_size = (alignment << 1) - pagesize;
		}

		if (run_size <= arena_maxclass) {
			ret = arena_palloc(choose_arena(), alignment, ceil_size,
			    run_size);
		} else if (alignment <= chunksize)
			ret = huge_malloc(ceil_size, false);
		else
			ret = huge_palloc(alignment, ceil_size);
	}

	assert(((uintptr_t)ret & (alignment - 1)) == 0);
	return (ret);
}

/* Return the size of the allocation pointed to by ptr. */
static size_t
arena_salloc(const void *ptr)
{
	size_t ret;
	arena_chunk_t *chunk;
	size_t pageind, mapbits;

	assert(ptr != NULL);
	assert(CHUNK_ADDR2BASE(ptr) != ptr);

	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
	mapbits = chunk->map[pageind].bits;
	assert((mapbits & CHUNK_MAP_ALLOCATED) != 0);
	if ((mapbits & CHUNK_MAP_LARGE) == 0) {
		arena_run_t *run = (arena_run_t *)(mapbits & ~pagesize_mask);
		assert(run->magic == ARENA_RUN_MAGIC);
		ret = run->bin->reg_size;
	} else {
		ret = mapbits & ~pagesize_mask;
		assert(ret != 0);
	}

	return (ret);
}

#if (defined(MALLOC_VALIDATE) || defined(MOZ_MEMORY_DARWIN))
/*
 * Validate ptr before assuming that it points to an allocation.  Currently,
 * the following validation is performed:
 *
 * + Check that ptr is not NULL.
 *
 * + Check that ptr lies within a mapped chunk.
 */
static inline size_t
isalloc_validate(const void *ptr)
{
	arena_chunk_t *chunk;

	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
	if (chunk == NULL)
		return (0);

	if (malloc_rtree_get(chunk_rtree, (uintptr_t)chunk) == NULL)
		return (0);

	if (chunk != ptr) {
		assert(chunk->arena->magic == ARENA_MAGIC);
		return (arena_salloc(ptr));
	} else {
		size_t ret;
		extent_node_t *node;
		extent_node_t key;

		/* Chunk. */
		key.addr = (void *)chunk;
		malloc_mutex_lock(&huge_mtx);
		node = extent_tree_ad_search(&huge, &key);
		if (node != NULL)
			ret = node->size;
		else
			ret = 0;
		malloc_mutex_unlock(&huge_mtx);
		return (ret);
	}
}
#endif

static inline size_t
isalloc(const void *ptr)
{
	size_t ret;
	arena_chunk_t *chunk;

	assert(ptr != NULL);

	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
	if (chunk != ptr) {
		/* Region. */
		assert(chunk->arena->magic == ARENA_MAGIC);

		ret = arena_salloc(ptr);
	} else {
		extent_node_t *node, key;

		/* Chunk (huge allocation). */

		malloc_mutex_lock(&huge_mtx);

		/* Extract from tree of huge allocations. */
		key.addr = __DECONST(void *, ptr);
		node = extent_tree_ad_search(&huge, &key);
		assert(node != NULL);

		ret = node->size;

		malloc_mutex_unlock(&huge_mtx);
	}

	return (ret);
}

static inline void
arena_dalloc_small(arena_t *arena, arena_chunk_t *chunk, void *ptr,
    arena_chunk_map_t *mapelm)
{
	arena_run_t *run;
	arena_bin_t *bin;
	size_t size;

	run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
	assert(run->magic == ARENA_RUN_MAGIC);
	bin = run->bin;
	size = bin->reg_size;

#ifdef MALLOC_FILL
	if (opt_junk)
		memset(ptr, 0x5a, size);
#endif

	arena_run_reg_dalloc(run, bin, ptr, size);
	run->nfree++;

	if (run->nfree == bin->nregs) {
		/* Deallocate run. */
		if (run == bin->runcur)
			bin->runcur = NULL;
		else if (bin->nregs != 1) {
			size_t run_pageind = (((uintptr_t)run -
			    (uintptr_t)chunk)) >> pagesize_2pow;
			arena_chunk_map_t *run_mapelm =
			    &chunk->map[run_pageind];
			/*
			 * This block's conditional is necessary because if the
			 * run only contains one region, then it never gets
			 * inserted into the non-full runs tree.
			 */
			assert(arena_run_tree_search(&bin->runs, run_mapelm) ==
			    run_mapelm);
			arena_run_tree_remove(&bin->runs, run_mapelm);
		}
#ifdef MALLOC_DEBUG
		run->magic = 0;
#endif
		VALGRIND_FREELIKE_BLOCK(run, 0);
		arena_run_dalloc(arena, run, true);
#ifdef MALLOC_STATS
		bin->stats.curruns--;
#endif
	} else if (run->nfree == 1 && run != bin->runcur) {
		/*
		 * Make sure that bin->runcur always refers to the lowest
		 * non-full run, if one exists.
		 */
		if (bin->runcur == NULL)
			bin->runcur = run;
		else if ((uintptr_t)run < (uintptr_t)bin->runcur) {
			/* Switch runcur. */
			if (bin->runcur->nfree > 0) {
				arena_chunk_t *runcur_chunk =
				    (arena_chunk_t*)CHUNK_ADDR2BASE(bin->runcur);
				size_t runcur_pageind =
				    (((uintptr_t)bin->runcur -
				    (uintptr_t)runcur_chunk)) >> pagesize_2pow;
				arena_chunk_map_t *runcur_mapelm =
				    &runcur_chunk->map[runcur_pageind];

				/* Insert runcur. */
				assert(arena_run_tree_search(&bin->runs,
				    runcur_mapelm) == NULL);
				arena_run_tree_insert(&bin->runs,
				    runcur_mapelm);
			}
			bin->runcur = run;
		} else {
			size_t run_pageind = (((uintptr_t)run -
			    (uintptr_t)chunk)) >> pagesize_2pow;
			arena_chunk_map_t *run_mapelm =
			    &chunk->map[run_pageind];

			assert(arena_run_tree_search(&bin->runs, run_mapelm) ==
			    NULL);
			arena_run_tree_insert(&bin->runs, run_mapelm);
		}
	}
#ifdef MALLOC_STATS
	arena->stats.allocated_small -= size;
	arena->stats.ndalloc_small++;
#endif
}

static void
arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk, void *ptr)
{
	/* Large allocation. */
	malloc_spin_lock(&arena->lock);

#ifdef MALLOC_FILL
#ifndef MALLOC_STATS
	if (opt_junk)
#endif
#endif
	{
		size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >>
		    pagesize_2pow;
		size_t size = chunk->map[pageind].bits & ~pagesize_mask;

#ifdef MALLOC_FILL
#ifdef MALLOC_STATS
		if (opt_junk)
#endif
			memset(ptr, 0x5a, size);
#endif
#ifdef MALLOC_STATS
		arena->stats.allocated_large -= size;
#endif
	}
#ifdef MALLOC_STATS
	arena->stats.ndalloc_large++;
#endif

	arena_run_dalloc(arena, (arena_run_t *)ptr, true);
	malloc_spin_unlock(&arena->lock);
}

static inline void
arena_dalloc(void *ptr, size_t offset)
{
	arena_chunk_t *chunk;
	arena_t *arena;
	size_t pageind;
	arena_chunk_map_t *mapelm;

	assert(ptr != NULL);
	assert(offset != 0);
	assert(CHUNK_ADDR2OFFSET(ptr) == offset);

	chunk = (arena_chunk_t *) ((uintptr_t)ptr - offset);
	arena = chunk->arena;
	assert(arena != NULL);
	assert(arena->magic == ARENA_MAGIC);

	pageind = offset >> pagesize_2pow;
	mapelm = &chunk->map[pageind];
	assert((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0);
	if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
		/* Small allocation. */
		malloc_spin_lock(&arena->lock);
		arena_dalloc_small(arena, chunk, ptr, mapelm);
		malloc_spin_unlock(&arena->lock);
	} else
		arena_dalloc_large(arena, chunk, ptr);
	VALGRIND_FREELIKE_BLOCK(ptr, 0);
}

static inline void
idalloc(void *ptr)
{
	size_t offset;

	assert(ptr != NULL);

	offset = CHUNK_ADDR2OFFSET(ptr);
	if (offset != 0)
		arena_dalloc(ptr, offset);
	else
		huge_dalloc(ptr);
}

static void
arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk, void *ptr,
    size_t size, size_t oldsize)
{

	assert(size < oldsize);

	/*
	 * Shrink the run, and make trailing pages available for other
	 * allocations.
	 */
#ifdef MALLOC_BALANCE
	arena_lock_balance(arena);
#else
	malloc_spin_lock(&arena->lock);
#endif
	arena_run_trim_tail(arena, chunk, (arena_run_t *)ptr, oldsize, size,
	    true);
#ifdef MALLOC_STATS
	arena->stats.allocated_large -= oldsize - size;
#endif
	malloc_spin_unlock(&arena->lock);
}

static bool
arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk, void *ptr,
    size_t size, size_t oldsize)
{
	size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow;
	size_t npages = oldsize >> pagesize_2pow;

	assert(oldsize == (chunk->map[pageind].bits & ~pagesize_mask));

	/* Try to extend the run. */
	assert(size > oldsize);
#ifdef MALLOC_BALANCE
	arena_lock_balance(arena);
#else
	malloc_spin_lock(&arena->lock);
#endif
	if (pageind + npages < chunk_npages && (chunk->map[pageind+npages].bits
	    & CHUNK_MAP_ALLOCATED) == 0 && (chunk->map[pageind+npages].bits &
	    ~pagesize_mask) >= size - oldsize) {
		/*
		 * The next run is available and sufficiently large.  Split the
		 * following run, then merge the first part with the existing
		 * allocation.
		 */
		arena_run_split(arena, (arena_run_t *)((uintptr_t)chunk +
		    ((pageind+npages) << pagesize_2pow)), size - oldsize, true,
		    false);

		chunk->map[pageind].bits = size | CHUNK_MAP_LARGE |
		    CHUNK_MAP_ALLOCATED;
		chunk->map[pageind+npages].bits = CHUNK_MAP_LARGE |
		    CHUNK_MAP_ALLOCATED;

#ifdef MALLOC_STATS
		arena->stats.allocated_large += size - oldsize;
#endif
		malloc_spin_unlock(&arena->lock);
		return (false);
	}
	malloc_spin_unlock(&arena->lock);

	return (true);
}

/*
 * Try to resize a large allocation, in order to avoid copying.  This will
 * always fail if growing an object, and the following run is already in use.
 */
static bool
arena_ralloc_large(void *ptr, size_t size, size_t oldsize)
{
	size_t psize;

	psize = PAGE_CEILING(size);
	if (psize == oldsize) {
		/* Same size class. */
#ifdef MALLOC_FILL
		if (opt_junk && size < oldsize) {
			memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize -
			    size);
		}
#endif
		return (false);
	} else {
		arena_chunk_t *chunk;
		arena_t *arena;

		chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
		arena = chunk->arena;
		assert(arena->magic == ARENA_MAGIC);

		if (psize < oldsize) {
#ifdef MALLOC_FILL
			/* Fill before shrinking in order avoid a race. */
			if (opt_junk) {
				memset((void *)((uintptr_t)ptr + size), 0x5a,
				    oldsize - size);
			}
#endif
			arena_ralloc_large_shrink(arena, chunk, ptr, psize,
			    oldsize);
			return (false);
		} else {
			bool ret = arena_ralloc_large_grow(arena, chunk, ptr,
			    psize, oldsize);
#ifdef MALLOC_FILL
			if (ret == false && opt_zero) {
				memset((void *)((uintptr_t)ptr + oldsize), 0,
				    size - oldsize);
			}
#endif
			return (ret);
		}
	}
}

static void *
arena_ralloc(void *ptr, size_t size, size_t oldsize)
{
	void *ret;
	size_t copysize;

	/* Try to avoid moving the allocation. */
	if (size < small_min) {
		if (oldsize < small_min &&
		    ffs((int)(pow2_ceil(size) >> (TINY_MIN_2POW + 1)))
		    == ffs((int)(pow2_ceil(oldsize) >> (TINY_MIN_2POW + 1))))
			goto IN_PLACE; /* Same size class. */
	} else if (size <= small_max) {
		if (oldsize >= small_min && oldsize <= small_max &&
		    (QUANTUM_CEILING(size) >> opt_quantum_2pow)
		    == (QUANTUM_CEILING(oldsize) >> opt_quantum_2pow))
			goto IN_PLACE; /* Same size class. */
	} else if (size <= bin_maxclass) {
		if (oldsize > small_max && oldsize <= bin_maxclass &&
		    pow2_ceil(size) == pow2_ceil(oldsize))
			goto IN_PLACE; /* Same size class. */
	} else if (oldsize > bin_maxclass && oldsize <= arena_maxclass) {
		assert(size > bin_maxclass);
		if (arena_ralloc_large(ptr, size, oldsize) == false)
			return (ptr);
	}

	/*
	 * If we get here, then size and oldsize are different enough that we
	 * need to move the object.  In that case, fall back to allocating new
	 * space and copying.
	 */
	ret = arena_malloc(choose_arena(), size, false);
	if (ret == NULL)
		return (NULL);

	/* Junk/zero-filling were already done by arena_malloc(). */
	copysize = (size < oldsize) ? size : oldsize;
#ifdef VM_COPY_MIN
	if (copysize >= VM_COPY_MIN)
		pages_copy(ret, ptr, copysize);
	else
#endif
		memcpy(ret, ptr, copysize);
	idalloc(ptr);
	return (ret);
IN_PLACE:
#ifdef MALLOC_FILL
	if (opt_junk && size < oldsize)
		memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize - size);
	else if (opt_zero && size > oldsize)
		memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize);
#endif
	return (ptr);
}

static inline void *
iralloc(void *ptr, size_t size)
{
	size_t oldsize;

	assert(ptr != NULL);
	assert(size != 0);

	oldsize = isalloc(ptr);

#ifndef MALLOC_VALGRIND
	if (size <= arena_maxclass)
		return (arena_ralloc(ptr, size, oldsize));
	else
		return (huge_ralloc(ptr, size, oldsize));
#else
	/*
	 * Valgrind does not provide a public interface for modifying an
	 * existing allocation, so use malloc/memcpy/free instead.
	 */
	{
		void *ret = imalloc(size);
		if (ret != NULL) {
			if (oldsize < size)
			    memcpy(ret, ptr, oldsize);
			else
			    memcpy(ret, ptr, size);
			idalloc(ptr);
		}
		return (ret);
	}
#endif
}

static bool
arena_new(arena_t *arena)
{
	unsigned i;
	arena_bin_t *bin;
	size_t pow2_size, prev_run_size;

	if (malloc_spin_init(&arena->lock))
		return (true);

#ifdef MALLOC_STATS
	memset(&arena->stats, 0, sizeof(arena_stats_t));
#endif

	/* Initialize chunks. */
	arena_chunk_tree_dirty_new(&arena->chunks_dirty);
	arena->spare = NULL;

	arena->ndirty = 0;

	arena_avail_tree_new(&arena->runs_avail);

#ifdef MALLOC_BALANCE
	arena->contention = 0;
#endif

	/* Initialize bins. */
	prev_run_size = pagesize;

	/* (2^n)-spaced tiny bins. */
	for (i = 0; i < ntbins; i++) {
		bin = &arena->bins[i];
		bin->runcur = NULL;
		arena_run_tree_new(&bin->runs);

		bin->reg_size = (1U << (TINY_MIN_2POW + i));

		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);

#ifdef MALLOC_STATS
		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
#endif
	}

	/* Quantum-spaced bins. */
	for (; i < ntbins + nqbins; i++) {
		bin = &arena->bins[i];
		bin->runcur = NULL;
		arena_run_tree_new(&bin->runs);

		bin->reg_size = quantum * (i - ntbins + 1);

		pow2_size = pow2_ceil(quantum * (i - ntbins + 1));
		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);

#ifdef MALLOC_STATS
		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
#endif
	}

	/* (2^n)-spaced sub-page bins. */
	for (; i < ntbins + nqbins + nsbins; i++) {
		bin = &arena->bins[i];
		bin->runcur = NULL;
		arena_run_tree_new(&bin->runs);

		bin->reg_size = (small_max << (i - (ntbins + nqbins) + 1));

		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);

#ifdef MALLOC_STATS
		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
#endif
	}

#ifdef MALLOC_DEBUG
	arena->magic = ARENA_MAGIC;
#endif

	return (false);
}

/* Create a new arena and insert it into the arenas array at index ind. */
static arena_t *
arenas_extend(unsigned ind)
{
	arena_t *ret;

	/* Allocate enough space for trailing bins. */
	ret = (arena_t *)base_alloc(sizeof(arena_t)
	    + (sizeof(arena_bin_t) * (ntbins + nqbins + nsbins - 1)));
	if (ret != NULL && arena_new(ret) == false) {
		arenas[ind] = ret;
		return (ret);
	}
	/* Only reached if there is an OOM error. */

	/*
	 * OOM here is quite inconvenient to propagate, since dealing with it
	 * would require a check for failure in the fast path.  Instead, punt
	 * by using arenas[0].  In practice, this is an extremely unlikely
	 * failure.
	 */
	_malloc_message(_getprogname(),
	    ": (malloc) Error initializing arena\n", "", "");
	if (opt_abort)
		abort();

	return (arenas[0]);
}

/*
 * End arena.
 */
/******************************************************************************/
/*
 * Begin general internal functions.
 */

static void *
huge_malloc(size_t size, bool zero)
{
	void *ret;
	size_t csize;
#ifdef MALLOC_DECOMMIT
	size_t psize;
#endif
	extent_node_t *node;

	/* Allocate one or more contiguous chunks for this request. */

	csize = CHUNK_CEILING(size);
	if (csize == 0) {
		/* size is large enough to cause size_t wrap-around. */
		return (NULL);
	}

	/* Allocate an extent node with which to track the chunk. */
	node = base_node_alloc();
	if (node == NULL)
		return (NULL);

	ret = chunk_alloc(csize, zero, true);
	if (ret == NULL) {
		base_node_dealloc(node);
		return (NULL);
	}

	/* Insert node into huge. */
	node->addr = ret;
#ifdef MALLOC_DECOMMIT
	psize = PAGE_CEILING(size);
	node->size = psize;
#else
	node->size = csize;
#endif

	malloc_mutex_lock(&huge_mtx);
	extent_tree_ad_insert(&huge, node);
#ifdef MALLOC_STATS
	huge_nmalloc++;
#  ifdef MALLOC_DECOMMIT
	huge_allocated += psize;
#  else
	huge_allocated += csize;
#  endif
#endif
	malloc_mutex_unlock(&huge_mtx);

#ifdef MALLOC_DECOMMIT
	if (csize - psize > 0)
		pages_decommit((void *)((uintptr_t)ret + psize), csize - psize);
#endif

#ifdef MALLOC_DECOMMIT
	VALGRIND_MALLOCLIKE_BLOCK(ret, psize, 0, zero);
#else
	VALGRIND_MALLOCLIKE_BLOCK(ret, csize, 0, zero);
#endif

#ifdef MALLOC_FILL
	if (zero == false) {
		if (opt_junk)
#  ifdef MALLOC_DECOMMIT
			memset(ret, 0xa5, psize);
#  else
			memset(ret, 0xa5, csize);
#  endif
		else if (opt_zero)
#  ifdef MALLOC_DECOMMIT
			memset(ret, 0, psize);
#  else
			memset(ret, 0, csize);
#  endif
	}
#endif

	return (ret);
}

/* Only handles large allocations that require more than chunk alignment. */
static void *
huge_palloc(size_t alignment, size_t size)
{
	void *ret;
	size_t alloc_size, chunk_size, offset;
#ifdef MALLOC_DECOMMIT
	size_t psize;
#endif
	extent_node_t *node;
	int pfd;

	/*
	 * This allocation requires alignment that is even larger than chunk
	 * alignment.  This means that huge_malloc() isn't good enough.
	 *
	 * Allocate almost twice as many chunks as are demanded by the size or
	 * alignment, in order to assure the alignment can be achieved, then
	 * unmap leading and trailing chunks.
	 */
	assert(alignment >= chunksize);

	chunk_size = CHUNK_CEILING(size);

	if (size >= alignment)
		alloc_size = chunk_size + alignment - chunksize;
	else
		alloc_size = (alignment << 1) - chunksize;

	/* Allocate an extent node with which to track the chunk. */
	node = base_node_alloc();
	if (node == NULL)
		return (NULL);

	/*
	 * Windows requires that there be a 1:1 mapping between VM
	 * allocation/deallocation operations.  Therefore, take care here to
	 * acquire the final result via one mapping operation.
	 *
	 * The MALLOC_PAGEFILE code also benefits from this mapping algorithm,
	 * since it reduces the number of page files.
	 */
#ifdef MALLOC_PAGEFILE
	if (opt_pagefile) {
		pfd = pagefile_init(size);
		if (pfd == -1)
			return (NULL);
	} else
#endif
		pfd = -1;
#ifdef JEMALLOC_USES_MAP_ALIGN
		ret = pages_map_align(chunk_size, pfd, alignment);
#else
	do {
		void *over;

		over = chunk_alloc(alloc_size, false, false);
		if (over == NULL) {
			base_node_dealloc(node);
			ret = NULL;
			goto RETURN;
		}

		offset = (uintptr_t)over & (alignment - 1);
		assert((offset & chunksize_mask) == 0);
		assert(offset < alloc_size);
		ret = (void *)((uintptr_t)over + offset);
		chunk_dealloc(over, alloc_size);
		ret = pages_map(ret, chunk_size, pfd);
		/*
		 * Failure here indicates a race with another thread, so try
		 * again.
		 */
	} while (ret == NULL);
#endif
	/* Insert node into huge. */
	node->addr = ret;
#ifdef MALLOC_DECOMMIT
	psize = PAGE_CEILING(size);
	node->size = psize;
#else
	node->size = chunk_size;
#endif

	malloc_mutex_lock(&huge_mtx);
	extent_tree_ad_insert(&huge, node);
#ifdef MALLOC_STATS
	huge_nmalloc++;
#  ifdef MALLOC_DECOMMIT
	huge_allocated += psize;
#  else
	huge_allocated += chunk_size;
#  endif
#endif
	malloc_mutex_unlock(&huge_mtx);

#ifdef MALLOC_DECOMMIT
	if (chunk_size - psize > 0) {
		pages_decommit((void *)((uintptr_t)ret + psize),
		    chunk_size - psize);
	}
#endif

#ifdef MALLOC_DECOMMIT
	VALGRIND_MALLOCLIKE_BLOCK(ret, psize, 0, false);
#else
	VALGRIND_MALLOCLIKE_BLOCK(ret, chunk_size, 0, false);
#endif

#ifdef MALLOC_FILL
	if (opt_junk)
#  ifdef MALLOC_DECOMMIT
		memset(ret, 0xa5, psize);
#  else
		memset(ret, 0xa5, chunk_size);
#  endif
	else if (opt_zero)
#  ifdef MALLOC_DECOMMIT
		memset(ret, 0, psize);
#  else
		memset(ret, 0, chunk_size);
#  endif
#endif

RETURN:
#ifdef MALLOC_PAGEFILE
	if (pfd != -1)
		pagefile_close(pfd);
#endif
	return (ret);
}

static void *
huge_ralloc(void *ptr, size_t size, size_t oldsize)
{
	void *ret;
	size_t copysize;

	/* Avoid moving the allocation if the size class would not change. */

	if (oldsize > arena_maxclass &&
	    CHUNK_CEILING(size) == CHUNK_CEILING(oldsize)) {
#ifdef MALLOC_DECOMMIT
		size_t psize = PAGE_CEILING(size);
#endif
#ifdef MALLOC_FILL
		if (opt_junk && size < oldsize) {
			memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize
			    - size);
		}
#endif
#ifdef MALLOC_DECOMMIT
		if (psize < oldsize) {
			extent_node_t *node, key;

			pages_decommit((void *)((uintptr_t)ptr + psize),
			    oldsize - psize);

			/* Update recorded size. */
			malloc_mutex_lock(&huge_mtx);
			key.addr = __DECONST(void *, ptr);
			node = extent_tree_ad_search(&huge, &key);
			assert(node != NULL);
			assert(node->size == oldsize);
#  ifdef MALLOC_STATS
			huge_allocated -= oldsize - psize;
#  endif
			node->size = psize;
			malloc_mutex_unlock(&huge_mtx);
		} else if (psize > oldsize) {
			extent_node_t *node, key;

			pages_commit((void *)((uintptr_t)ptr + oldsize),
			    psize - oldsize);

			/* Update recorded size. */
			malloc_mutex_lock(&huge_mtx);
			key.addr = __DECONST(void *, ptr);
			node = extent_tree_ad_search(&huge, &key);
			assert(node != NULL);
			assert(node->size == oldsize);
#  ifdef MALLOC_STATS
			huge_allocated += psize - oldsize;
#  endif
			node->size = psize;
			malloc_mutex_unlock(&huge_mtx);
		}
#endif
#ifdef MALLOC_FILL
		if (opt_zero && size > oldsize) {
			memset((void *)((uintptr_t)ptr + oldsize), 0, size
			    - oldsize);
		}
#endif
		return (ptr);
	}

	/*
	 * If we get here, then size and oldsize are different enough that we
	 * need to use a different size class.  In that case, fall back to
	 * allocating new space and copying.
	 */
	ret = huge_malloc(size, false);
	if (ret == NULL)
		return (NULL);

	copysize = (size < oldsize) ? size : oldsize;
#ifdef VM_COPY_MIN
	if (copysize >= VM_COPY_MIN)
		pages_copy(ret, ptr, copysize);
	else
#endif
		memcpy(ret, ptr, copysize);
	idalloc(ptr);
	return (ret);
}

static void
huge_dalloc(void *ptr)
{
	extent_node_t *node, key;

	malloc_mutex_lock(&huge_mtx);

	/* Extract from tree of huge allocations. */
	key.addr = ptr;
	node = extent_tree_ad_search(&huge, &key);
	assert(node != NULL);
	assert(node->addr == ptr);
	extent_tree_ad_remove(&huge, node);

#ifdef MALLOC_STATS
	huge_ndalloc++;
	huge_allocated -= node->size;
#endif

	malloc_mutex_unlock(&huge_mtx);

	/* Unmap chunk. */
#ifdef MALLOC_FILL
	if (opt_junk)
		memset(node->addr, 0x5a, node->size);
#endif
#ifdef MALLOC_DECOMMIT
	chunk_dealloc(node->addr, CHUNK_CEILING(node->size));
#else
	chunk_dealloc(node->addr, node->size);
#endif
	VALGRIND_FREELIKE_BLOCK(node->addr, 0);

	base_node_dealloc(node);
}

#ifndef MOZ_MEMORY_NARENAS_DEFAULT_ONE
#ifdef MOZ_MEMORY_BSD
static inline unsigned
malloc_ncpus(void)
{
	unsigned ret;
	int mib[2];
	size_t len;

	mib[0] = CTL_HW;
	mib[1] = HW_NCPU;
	len = sizeof(ret);
	if (sysctl(mib, 2, &ret, &len, (void *) 0, 0) == -1) {
		/* Error. */
		return (1);
	}

	return (ret);
}
#elif (defined(MOZ_MEMORY_LINUX))
#include <fcntl.h>

static inline unsigned
malloc_ncpus(void)
{
	unsigned ret;
	int fd, nread, column;
	char buf[1024];
	static const char matchstr[] = "processor\t:";
	int i;

	/*
	 * sysconf(3) would be the preferred method for determining the number
	 * of CPUs, but it uses malloc internally, which causes untennable
	 * recursion during malloc initialization.
	 */
	fd = open("/proc/cpuinfo", O_RDONLY);
	if (fd == -1)
		return (1); /* Error. */
	/*
	 * Count the number of occurrences of matchstr at the beginnings of
	 * lines.  This treats hyperthreaded CPUs as multiple processors.
	 */
	column = 0;
	ret = 0;
	while (true) {
		nread = read(fd, &buf, sizeof(buf));
		if (nread <= 0)
			break; /* EOF or error. */
		for (i = 0;i < nread;i++) {
			char c = buf[i];
			if (c == '\n')
				column = 0;
			else if (column != -1) {
				if (c == matchstr[column]) {
					column++;
					if (column == sizeof(matchstr) - 1) {
						column = -1;
						ret++;
					}
				} else
					column = -1;
			}
		}
	}

	if (ret == 0)
		ret = 1; /* Something went wrong in the parser. */
	close(fd);

	return (ret);
}
#elif (defined(MOZ_MEMORY_DARWIN))
#include <mach/mach_init.h>
#include <mach/mach_host.h>

static inline unsigned
malloc_ncpus(void)
{
	kern_return_t error;
	natural_t n;
	processor_info_array_t pinfo;
	mach_msg_type_number_t pinfocnt;

	error = host_processor_info(mach_host_self(), PROCESSOR_BASIC_INFO,
				    &n, &pinfo, &pinfocnt);
	if (error != KERN_SUCCESS)
		return (1); /* Error. */
	else
		return (n);
}
#elif (defined(MOZ_MEMORY_SOLARIS))

static inline unsigned
malloc_ncpus(void)
{
	return sysconf(_SC_NPROCESSORS_ONLN);
}
#else
static inline unsigned
malloc_ncpus(void)
{

	/*
	 * We lack a way to determine the number of CPUs on this platform, so
	 * assume 1 CPU.
	 */
	return (1);
}
#endif
#endif

static void
malloc_print_stats(void)
{

	if (opt_print_stats) {
		char s[UMAX2S_BUFSIZE];
		_malloc_message("___ Begin malloc statistics ___\n", "", "",
		    "");
		_malloc_message("Assertions ",
#ifdef NDEBUG
		    "disabled",
#else
		    "enabled",
#endif
		    "\n", "");
		_malloc_message("Boolean MALLOC_OPTIONS: ",
		    opt_abort ? "A" : "a", "", "");
#ifdef MALLOC_FILL
		_malloc_message(opt_junk ? "J" : "j", "", "", "");
#endif
#ifdef MALLOC_PAGEFILE
		_malloc_message(opt_pagefile ? "o" : "O", "", "", "");
#endif
		_malloc_message("P", "", "", "");
#ifdef MALLOC_UTRACE
		_malloc_message(opt_utrace ? "U" : "u", "", "", "");
#endif
#ifdef MALLOC_SYSV
		_malloc_message(opt_sysv ? "V" : "v", "", "", "");
#endif
#ifdef MALLOC_XMALLOC
		_malloc_message(opt_xmalloc ? "X" : "x", "", "", "");
#endif
#ifdef MALLOC_FILL
		_malloc_message(opt_zero ? "Z" : "z", "", "", "");
#endif
		_malloc_message("\n", "", "", "");

#ifndef MOZ_MEMORY_NARENAS_DEFAULT_ONE
		_malloc_message("CPUs: ", umax2s(ncpus, s), "\n", "");
#endif
		_malloc_message("Max arenas: ", umax2s(narenas, s), "\n", "");
#ifdef MALLOC_BALANCE
		_malloc_message("Arena balance threshold: ",
		    umax2s(opt_balance_threshold, s), "\n", "");
#endif
		_malloc_message("Pointer size: ", umax2s(sizeof(void *), s),
		    "\n", "");
		_malloc_message("Quantum size: ", umax2s(quantum, s), "\n", "");
		_malloc_message("Max small size: ", umax2s(small_max, s), "\n",
		    "");
		_malloc_message("Max dirty pages per arena: ",
		    umax2s(opt_dirty_max, s), "\n", "");

		_malloc_message("Chunk size: ", umax2s(chunksize, s), "", "");
		_malloc_message(" (2^", umax2s(opt_chunk_2pow, s), ")\n", "");

#ifdef MALLOC_STATS
		{
			size_t allocated, mapped;
#ifdef MALLOC_BALANCE
			uint64_t nbalance = 0;
#endif
			unsigned i;
			arena_t *arena;

			/* Calculate and print allocated/mapped stats. */

			/* arenas. */
			for (i = 0, allocated = 0; i < narenas; i++) {
				if (arenas[i] != NULL) {
					malloc_spin_lock(&arenas[i]->lock);
					allocated +=
					    arenas[i]->stats.allocated_small;
					allocated +=
					    arenas[i]->stats.allocated_large;
#ifdef MALLOC_BALANCE
					nbalance += arenas[i]->stats.nbalance;
#endif
					malloc_spin_unlock(&arenas[i]->lock);
				}
			}

			/* huge/base. */
			malloc_mutex_lock(&huge_mtx);
			allocated += huge_allocated;
			mapped = stats_chunks.curchunks * chunksize;
			malloc_mutex_unlock(&huge_mtx);

			malloc_mutex_lock(&base_mtx);
			mapped += base_mapped;
			malloc_mutex_unlock(&base_mtx);

#ifdef MOZ_MEMORY_WINDOWS
			malloc_printf("Allocated: %lu, mapped: %lu\n",
			    allocated, mapped);
#else
			malloc_printf("Allocated: %zu, mapped: %zu\n",
			    allocated, mapped);
#endif

#ifdef MALLOC_BALANCE
			malloc_printf("Arena balance reassignments: %llu\n",
			    nbalance);
#endif

			/* Print chunk stats. */
			{
				chunk_stats_t chunks_stats;

				malloc_mutex_lock(&huge_mtx);
				chunks_stats = stats_chunks;
				malloc_mutex_unlock(&huge_mtx);

				malloc_printf("chunks: nchunks   "
				    "highchunks    curchunks\n");
				malloc_printf("  %13llu%13lu%13lu\n",
				    chunks_stats.nchunks,
				    chunks_stats.highchunks,
				    chunks_stats.curchunks);
			}

			/* Print chunk stats. */
			malloc_printf(
			    "huge: nmalloc      ndalloc    allocated\n");
#ifdef MOZ_MEMORY_WINDOWS
			malloc_printf(" %12llu %12llu %12lu\n",
			    huge_nmalloc, huge_ndalloc, huge_allocated);
#else
			malloc_printf(" %12llu %12llu %12zu\n",
			    huge_nmalloc, huge_ndalloc, huge_allocated);
#endif
			/* Print stats for each arena. */
			for (i = 0; i < narenas; i++) {
				arena = arenas[i];
				if (arena != NULL) {
					malloc_printf(
					    "\narenas[%u]:\n", i);
					malloc_spin_lock(&arena->lock);
					stats_print(arena);
					malloc_spin_unlock(&arena->lock);
				}
			}
		}
#endif /* #ifdef MALLOC_STATS */
		_malloc_message("--- End malloc statistics ---\n", "", "", "");
	}
}

/*
 * FreeBSD's pthreads implementation calls malloc(3), so the malloc
 * implementation has to take pains to avoid infinite recursion during
 * initialization.
 */
#if (defined(MOZ_MEMORY_WINDOWS) || defined(MOZ_MEMORY_DARWIN)) && !defined(MOZ_MEMORY_WINCE)
#define	malloc_init() false
#else
static inline bool
malloc_init(void)
{

	if (malloc_initialized == false)
		return (malloc_init_hard());

	return (false);
}
#endif

#if !defined(MOZ_MEMORY_WINDOWS) || defined(MOZ_MEMORY_WINCE) 
static
#endif
bool
malloc_init_hard(void)
{
	unsigned i;
	char buf[PATH_MAX + 1];
	const char *opts;
	long result;
#ifndef MOZ_MEMORY_WINDOWS
	int linklen;
#endif

#ifndef MOZ_MEMORY_WINDOWS
	malloc_mutex_lock(&init_lock);
#endif

	if (malloc_initialized) {
		/*
		 * Another thread initialized the allocator before this one
		 * acquired init_lock.
		 */
#ifndef MOZ_MEMORY_WINDOWS
		malloc_mutex_unlock(&init_lock);
#endif
		return (false);
	}

#ifdef MOZ_MEMORY_WINDOWS
	/* get a thread local storage index */
	tlsIndex = TlsAlloc();
#endif

	/* Get page size and number of CPUs */
#ifdef MOZ_MEMORY_WINDOWS
	{
		SYSTEM_INFO info;

		GetSystemInfo(&info);
		result = info.dwPageSize;

		pagesize = (unsigned) result;

#ifndef MOZ_MEMORY_NARENAS_DEFAULT_ONE
		ncpus = info.dwNumberOfProcessors;
#endif
	}
#else
#ifndef MOZ_MEMORY_NARENAS_DEFAULT_ONE
	ncpus = malloc_ncpus();
#endif

	result = sysconf(_SC_PAGESIZE);
	assert(result != -1);

	pagesize = (unsigned) result;
#endif

	/*
	 * We assume that pagesize is a power of 2 when calculating
	 * pagesize_mask and pagesize_2pow.
	 */
	assert(((result - 1) & result) == 0);
	pagesize_mask = result - 1;
	pagesize_2pow = ffs((int)result) - 1;

#ifdef MALLOC_PAGEFILE
	/*
	 * Determine where to create page files.  It is insufficient to
	 * unconditionally use P_tmpdir (typically "/tmp"), since for some
	 * operating systems /tmp is a separate filesystem that is rather small.
	 * Therefore prefer, in order, the following locations:
	 *
	 * 1) MALLOC_TMPDIR
	 * 2) TMPDIR
	 * 3) P_tmpdir
	 */
	{
		char *s;
		size_t slen;
		static const char suffix[] = "/jemalloc.XXXXXX";

		if ((s = getenv("MALLOC_TMPDIR")) == NULL && (s =
		    getenv("TMPDIR")) == NULL)
			s = P_tmpdir;
		slen = strlen(s);
		if (slen + sizeof(suffix) > sizeof(pagefile_templ)) {
			_malloc_message(_getprogname(),
			    ": (malloc) Page file path too long\n",
			    "", "");
			abort();
		}
		memcpy(pagefile_templ, s, slen);
		memcpy(&pagefile_templ[slen], suffix, sizeof(suffix));
	}
#endif

	for (i = 0; i < 3; i++) {
		unsigned j;

		/* Get runtime configuration. */
		switch (i) {
		case 0:
#ifndef MOZ_MEMORY_WINDOWS
			if ((linklen = readlink("/etc/malloc.conf", buf,
						sizeof(buf) - 1)) != -1) {
				/*
				 * Use the contents of the "/etc/malloc.conf"
				 * symbolic link's name.
				 */
				buf[linklen] = '\0';
				opts = buf;
			} else
#endif
			{
				/* No configuration specified. */
				buf[0] = '\0';
				opts = buf;
			}
			break;
		case 1:
			if (issetugid() == 0 && (opts =
			    getenv("MALLOC_OPTIONS")) != NULL) {
				/*
				 * Do nothing; opts is already initialized to
				 * the value of the MALLOC_OPTIONS environment
				 * variable.
				 */
			} else {
				/* No configuration specified. */
				buf[0] = '\0';
				opts = buf;
			}
			break;
		case 2:
			if (_malloc_options != NULL) {
				/*
				 * Use options that were compiled into the
				 * program.
				 */
				opts = _malloc_options;
			} else {
				/* No configuration specified. */
				buf[0] = '\0';
				opts = buf;
			}
			break;
		default:
			/* NOTREACHED */
			buf[0] = '\0';
			opts = buf;
			assert(false);
		}

		for (j = 0; opts[j] != '\0'; j++) {
			unsigned k, nreps;
			bool nseen;

			/* Parse repetition count, if any. */
			for (nreps = 0, nseen = false;; j++, nseen = true) {
				switch (opts[j]) {
					case '0': case '1': case '2': case '3':
					case '4': case '5': case '6': case '7':
					case '8': case '9':
						nreps *= 10;
						nreps += opts[j] - '0';
						break;
					default:
						goto MALLOC_OUT;
				}
			}
MALLOC_OUT:
			if (nseen == false)
				nreps = 1;

			for (k = 0; k < nreps; k++) {
				switch (opts[j]) {
				case 'a':
					opt_abort = false;
					break;
				case 'A':
					opt_abort = true;
					break;
				case 'b':
#ifdef MALLOC_BALANCE
					opt_balance_threshold >>= 1;
#endif
					break;
				case 'B':
#ifdef MALLOC_BALANCE
					if (opt_balance_threshold == 0)
						opt_balance_threshold = 1;
					else if ((opt_balance_threshold << 1)
					    > opt_balance_threshold)
						opt_balance_threshold <<= 1;
#endif
					break;
				case 'f':
					opt_dirty_max >>= 1;
					break;
				case 'F':
					if (opt_dirty_max == 0)
						opt_dirty_max = 1;
					else if ((opt_dirty_max << 1) != 0)
						opt_dirty_max <<= 1;
					break;
#ifdef MALLOC_FILL
				case 'j':
					opt_junk = false;
					break;
				case 'J':
					opt_junk = true;
					break;
#endif
				case 'k':
					/*
					 * Chunks always require at least one
					 * header page, so chunks can never be
					 * smaller than two pages.
					 */
					if (opt_chunk_2pow > pagesize_2pow + 1)
						opt_chunk_2pow--;
					break;
				case 'K':
					if (opt_chunk_2pow + 1 <
					    (sizeof(size_t) << 3))
						opt_chunk_2pow++;
					break;
				case 'n':
					opt_narenas_lshift--;
					break;
				case 'N':
					opt_narenas_lshift++;
					break;
#ifdef MALLOC_PAGEFILE
				case 'o':
					/* Do not over-commit. */
					opt_pagefile = true;
					break;
				case 'O':
					/* Allow over-commit. */
					opt_pagefile = false;
					break;
#endif
				case 'p':
					opt_print_stats = false;
					break;
				case 'P':
					opt_print_stats = true;
					break;
				case 'q':
					if (opt_quantum_2pow > QUANTUM_2POW_MIN)
						opt_quantum_2pow--;
					break;
				case 'Q':
					if (opt_quantum_2pow < pagesize_2pow -
					    1)
						opt_quantum_2pow++;
					break;
				case 's':
					if (opt_small_max_2pow >
					    QUANTUM_2POW_MIN)
						opt_small_max_2pow--;
					break;
				case 'S':
					if (opt_small_max_2pow < pagesize_2pow
					    - 1)
						opt_small_max_2pow++;
					break;
#ifdef MALLOC_UTRACE
				case 'u':
					opt_utrace = false;
					break;
				case 'U':
					opt_utrace = true;
					break;
#endif
#ifdef MALLOC_SYSV
				case 'v':
					opt_sysv = false;
					break;
				case 'V':
					opt_sysv = true;
					break;
#endif
#ifdef MALLOC_XMALLOC
				case 'x':
					opt_xmalloc = false;
					break;
				case 'X':
					opt_xmalloc = true;
					break;
#endif
#ifdef MALLOC_FILL
				case 'z':
					opt_zero = false;
					break;
				case 'Z':
					opt_zero = true;
					break;
#endif
				default: {
					char cbuf[2];

					cbuf[0] = opts[j];
					cbuf[1] = '\0';
					_malloc_message(_getprogname(),
					    ": (malloc) Unsupported character "
					    "in malloc options: '", cbuf,
					    "'\n");
				}
				}
			}
		}
	}

	/* Take care to call atexit() only once. */
	if (opt_print_stats) {
#ifndef MOZ_MEMORY_WINDOWS
		/* Print statistics at exit. */
		atexit(malloc_print_stats);
#endif
	}

#if (!defined(MOZ_MEMORY_WINDOWS) && !defined(MOZ_MEMORY_DARWIN) && !defined(MOZ_MEMORY_ANDROID))
	/* Prevent potential deadlock on malloc locks after fork. */
	pthread_atfork(_malloc_prefork, _malloc_postfork, _malloc_postfork);
#endif

	/* Set variables according to the value of opt_small_max_2pow. */
	if (opt_small_max_2pow < opt_quantum_2pow)
		opt_small_max_2pow = opt_quantum_2pow;
	small_max = (1U << opt_small_max_2pow);

	/* Set bin-related variables. */
	bin_maxclass = (pagesize >> 1);
	assert(opt_quantum_2pow >= TINY_MIN_2POW);
	ntbins = opt_quantum_2pow - TINY_MIN_2POW;
	assert(ntbins <= opt_quantum_2pow);
	nqbins = (small_max >> opt_quantum_2pow);
	nsbins = pagesize_2pow - opt_small_max_2pow - 1;

	/* Set variables according to the value of opt_quantum_2pow. */
	quantum = (1U << opt_quantum_2pow);
	quantum_mask = quantum - 1;
	if (ntbins > 0)
		small_min = (quantum >> 1) + 1;
	else
		small_min = 1;
	assert(small_min <= quantum);

	/* Set variables according to the value of opt_chunk_2pow. */
	chunksize = (1LU << opt_chunk_2pow);
	chunksize_mask = chunksize - 1;
	chunk_npages = (chunksize >> pagesize_2pow);
	{
		size_t header_size;

		/*
		 * Compute the header size such that it is large
		 * enough to contain the page map and enough nodes for the
		 * worst case: one node per non-header page plus one extra for
		 * situations where we briefly have one more node allocated
		 * than we will need.
		 */
		header_size = sizeof(arena_chunk_t) +
		    (sizeof(arena_chunk_map_t) * (chunk_npages - 1));
		arena_chunk_header_npages = (header_size >> pagesize_2pow) +
		    ((header_size & pagesize_mask) != 0);
	}
	arena_maxclass = chunksize - (arena_chunk_header_npages <<
	    pagesize_2pow);

#ifdef JEMALLOC_USES_MAP_ALIGN
	/*
	 * When using MAP_ALIGN, the alignment parameter must be a power of two
	 * multiple of the system pagesize, or mmap will fail.
	 */
	assert((chunksize % pagesize) == 0);
	assert((1 << (ffs(chunksize / pagesize) - 1)) == (chunksize/pagesize));
#endif

	UTRACE(0, 0, 0);

#ifdef MALLOC_STATS
	memset(&stats_chunks, 0, sizeof(chunk_stats_t));
#endif

	/* Various sanity checks that regard configuration. */
	assert(quantum >= sizeof(void *));
	assert(quantum <= pagesize);
	assert(chunksize >= pagesize);
	assert(quantum * 4 <= chunksize);

	/* Initialize chunks data. */
	malloc_mutex_init(&huge_mtx);
	extent_tree_ad_new(&huge);
#ifdef MALLOC_STATS
	huge_nmalloc = 0;
	huge_ndalloc = 0;
	huge_allocated = 0;
#endif

	/* Initialize base allocation data structures. */
#ifdef MALLOC_STATS
	base_mapped = 0;
#  ifdef MALLOC_DECOMMIT
	base_committed = 0;
#  endif
#endif
	base_nodes = NULL;
	malloc_mutex_init(&base_mtx);

#ifdef MOZ_MEMORY_NARENAS_DEFAULT_ONE
	narenas = 1;
#else
	if (ncpus > 1) {
		/*
		 * For SMP systems, create four times as many arenas as there
		 * are CPUs by default.
		 */
		opt_narenas_lshift += 2;
	}

	/* Determine how many arenas to use. */
	narenas = ncpus;
#endif
	if (opt_narenas_lshift > 0) {
		if ((narenas << opt_narenas_lshift) > narenas)
			narenas <<= opt_narenas_lshift;
		/*
		 * Make sure not to exceed the limits of what base_alloc() can
		 * handle.
		 */
		if (narenas * sizeof(arena_t *) > chunksize)
			narenas = chunksize / sizeof(arena_t *);
	} else if (opt_narenas_lshift < 0) {
		if ((narenas >> -opt_narenas_lshift) < narenas)
			narenas >>= -opt_narenas_lshift;
		/* Make sure there is at least one arena. */
		if (narenas == 0)
			narenas = 1;
	}
#ifdef MALLOC_BALANCE
	assert(narenas != 0);
	for (narenas_2pow = 0;
	     (narenas >> (narenas_2pow + 1)) != 0;
	     narenas_2pow++);
#endif

#ifdef NO_TLS
	if (narenas > 1) {
		static const unsigned primes[] = {1, 3, 5, 7, 11, 13, 17, 19,
		    23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83,
		    89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
		    151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211,
		    223, 227, 229, 233, 239, 241, 251, 257, 263};
		unsigned nprimes, parenas;

		/*
		 * Pick a prime number of hash arenas that is more than narenas
		 * so that direct hashing of pthread_self() pointers tends to
		 * spread allocations evenly among the arenas.
		 */
		assert((narenas & 1) == 0); /* narenas must be even. */
		nprimes = (sizeof(primes) >> SIZEOF_INT_2POW);
		parenas = primes[nprimes - 1]; /* In case not enough primes. */
		for (i = 1; i < nprimes; i++) {
			if (primes[i] > narenas) {
				parenas = primes[i];
				break;
			}
		}
		narenas = parenas;
	}
#endif

#ifndef NO_TLS
#  ifndef MALLOC_BALANCE
	next_arena = 0;
#  endif
#endif

	/* Allocate and initialize arenas. */
	arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas);
	if (arenas == NULL) {
#ifndef MOZ_MEMORY_WINDOWS
		malloc_mutex_unlock(&init_lock);
#endif
		return (true);
	}
	/*
	 * Zero the array.  In practice, this should always be pre-zeroed,
	 * since it was just mmap()ed, but let's be sure.
	 */
	memset(arenas, 0, sizeof(arena_t *) * narenas);

	/*
	 * Initialize one arena here.  The rest are lazily created in
	 * choose_arena_hard().
	 */
	arenas_extend(0);
	if (arenas[0] == NULL) {
#ifndef MOZ_MEMORY_WINDOWS
		malloc_mutex_unlock(&init_lock);
#endif
		return (true);
	}
#ifndef NO_TLS
	/*
	 * Assign the initial arena to the initial thread, in order to avoid
	 * spurious creation of an extra arena if the application switches to
	 * threaded mode.
	 */
#ifdef MOZ_MEMORY_WINDOWS
	TlsSetValue(tlsIndex, arenas[0]);
#else
	arenas_map = arenas[0];
#endif
#endif

	/*
	 * Seed here for the initial thread, since choose_arena_hard() is only
	 * called for other threads.  The seed value doesn't really matter.
	 */
#ifdef MALLOC_BALANCE
	SPRN(balance, 42);
#endif

	malloc_spin_init(&arenas_lock);

#ifdef MALLOC_VALIDATE
	chunk_rtree = malloc_rtree_new((SIZEOF_PTR << 3) - opt_chunk_2pow);
	if (chunk_rtree == NULL)
		return (true);
#endif

	malloc_initialized = true;
#ifndef MOZ_MEMORY_WINDOWS
	malloc_mutex_unlock(&init_lock);
#endif
	return (false);
}

/* XXX Why not just expose malloc_print_stats()? */
#ifdef MOZ_MEMORY_WINDOWS
void
malloc_shutdown()
{

	malloc_print_stats();
}
#endif

/*
 * End general internal functions.
 */
/******************************************************************************/
/*
 * Begin malloc(3)-compatible functions.
 */

/*
 * Inline the standard malloc functions if they are being subsumed by Darwin's
 * zone infrastructure.
 */
#ifdef MOZ_MEMORY_DARWIN
#  define ZONE_INLINE	inline
#else
#  define ZONE_INLINE
#endif

/* Mangle standard interfaces on Darwin and Android, 
   in order to avoid linking problems. */
#if defined(MOZ_MEMORY_DARWIN)
#define	malloc(a)	moz_malloc(a)
#define	valloc(a)	moz_valloc(a)
#define	calloc(a, b)	moz_calloc(a, b)
#define	realloc(a, b)	moz_realloc(a, b)
#define	free(a)		moz_free(a)
#endif

#if defined(MOZ_MEMORY_ANDROID) || defined(WRAP_MALLOC)
inline void sys_free(void* ptr) {return free(ptr);}
#define	malloc(a)	je_malloc(a)
#define	valloc(a)	je_valloc(a)
#define	calloc(a, b)	je_calloc(a, b)
#define	realloc(a, b)	je_realloc(a, b)
#define	free(a)		je_free(a)
#define posix_memalign(a, b, c)  je_posix_memalign(a, b, c)

char    *je_strndup(const char *src, size_t len) {
  char* dst = (char*)je_malloc(len + 1);
  if(dst)
    strncpy(dst, src, len + 1);
  return dst;
}
char    *je_strdup(const char *src) {
  size_t len = strlen(src);
  return je_strndup(src, len );
}
#endif

ZONE_INLINE
void *
malloc(size_t size)
{
	void *ret;

	if (malloc_init()) {
		ret = NULL;
		goto RETURN;
	}

	if (size == 0) {
#ifdef MALLOC_SYSV
		if (opt_sysv == false)
#endif
			size = 1;
#ifdef MALLOC_SYSV
		else {
			ret = NULL;
			goto RETURN;
		}
#endif
	}

	ret = imalloc(size);

RETURN:
	if (ret == NULL) {
#ifdef MALLOC_XMALLOC
		if (opt_xmalloc) {
			_malloc_message(_getprogname(),
			    ": (malloc) Error in malloc(): out of memory\n", "",
			    "");
			abort();
		}
#endif
		errno = ENOMEM;
	}

	UTRACE(0, size, ret);
	return (ret);
}

/* In ELF systems the default visibility allows symbols to be preempted at
   runtime. This in turn prevents the uses of memalign in this file from
   being optimized. What we do in here is define two aliasing symbols
   (they point to the same code): memalign and memalign_internal.
   The internal version has hidden visibility and is used in every reference
   from this file.
   For more information on this technique, see section 2.2.7
   (Avoid Using Exported Symbols) in
   http://www.akkadia.org/drepper/dsohowto.pdf */
#ifdef MOZ_MEMORY_SOLARIS
#  ifdef __SUNPRO_C
void *
memalign(size_t alignment, size_t size);
#pragma no_inline(memalign)
#  elif (defined(__GNU_C__))
__attribute__((noinline))
#  endif
#else
#if (defined(__GNUC__))
__attribute__((visibility ("hidden")))
#endif
#endif

#if (defined(__GNUC__))
#define MEMALIGN memalign_internal
#else
#define MEMALIGN memalign
#endif

void *
MEMALIGN(size_t alignment, size_t size)
{
	void *ret;

	assert(((alignment - 1) & alignment) == 0);

	if (malloc_init()) {
		ret = NULL;
		goto RETURN;
	}

	if (size == 0) {
#ifdef MALLOC_SYSV
		if (opt_sysv == false)
#endif
			size = 1;
#ifdef MALLOC_SYSV
		else {
			ret = NULL;
			goto RETURN;
		}
#endif
	}

	alignment = alignment < sizeof(void*) ? sizeof(void*) : alignment;
	ret = ipalloc(alignment, size);

RETURN:
#ifdef MALLOC_XMALLOC
	if (opt_xmalloc && ret == NULL) {
		_malloc_message(_getprogname(),
		": (malloc) Error in memalign(): out of memory\n", "", "");
		abort();
	}
#endif
	UTRACE(0, size, ret);
	return (ret);
}

#if (defined(__GNUC__))
extern __typeof(memalign_internal)
        memalign __attribute__((alias ("memalign_internal"),
				visibility ("default")));
#endif

ZONE_INLINE
int
posix_memalign(void **memptr, size_t alignment, size_t size)
{
	void *result;

	/* Make sure that alignment is a large enough power of 2. */
	if (((alignment - 1) & alignment) != 0 || alignment < sizeof(void *)) {
#ifdef MALLOC_XMALLOC
		if (opt_xmalloc) {
			_malloc_message(_getprogname(),
			    ": (malloc) Error in posix_memalign(): "
			    "invalid alignment\n", "", "");
			abort();
		}
#endif
		return (EINVAL);
	}

	/* The 0-->1 size promotion is done in the memalign() call below */

#ifdef MOZ_MEMORY_DARWIN
	result = moz_memalign(alignment, size);
#else
	result = MEMALIGN(alignment, size);
#endif
	if (result == NULL)
		return (ENOMEM);

	*memptr = result;
	return (0);
}

ZONE_INLINE
void *
valloc(size_t size)
{
#ifdef MOZ_MEMORY_DARWIN
	return (moz_memalign(pagesize, size));
#else
	return (MEMALIGN(pagesize, size));
#endif
}

ZONE_INLINE
void *
calloc(size_t num, size_t size)
{
	void *ret;
	size_t num_size;

	if (malloc_init()) {
		num_size = 0;
		ret = NULL;
		goto RETURN;
	}

	num_size = num * size;
	if (num_size == 0) {
#ifdef MALLOC_SYSV
		if ((opt_sysv == false) && ((num == 0) || (size == 0)))
#endif
			num_size = 1;
#ifdef MALLOC_SYSV
		else {
			ret = NULL;
			goto RETURN;
		}
#endif
	/*
	 * Try to avoid division here.  We know that it isn't possible to
	 * overflow during multiplication if neither operand uses any of the
	 * most significant half of the bits in a size_t.
	 */
	} else if (((num | size) & (SIZE_T_MAX << (sizeof(size_t) << 2)))
	    && (num_size / size != num)) {
		/* size_t overflow. */
		ret = NULL;
		goto RETURN;
	}

	ret = icalloc(num_size);

RETURN:
	if (ret == NULL) {
#ifdef MALLOC_XMALLOC
		if (opt_xmalloc) {
			_malloc_message(_getprogname(),
			    ": (malloc) Error in calloc(): out of memory\n", "",
			    "");
			abort();
		}
#endif
		errno = ENOMEM;
	}

	UTRACE(0, num_size, ret);
	return (ret);
}

ZONE_INLINE
void *
realloc(void *ptr, size_t size)
{
	void *ret;

	if (size == 0) {
#ifdef MALLOC_SYSV
		if (opt_sysv == false)
#endif
			size = 1;
#ifdef MALLOC_SYSV
		else {
			if (ptr != NULL)
				idalloc(ptr);
			ret = NULL;
			goto RETURN;
		}
#endif
	}

	if (ptr != NULL) {
		assert(malloc_initialized);

		ret = iralloc(ptr, size);

		if (ret == NULL) {
#ifdef MALLOC_XMALLOC
			if (opt_xmalloc) {
				_malloc_message(_getprogname(),
				    ": (malloc) Error in realloc(): out of "
				    "memory\n", "", "");
				abort();
			}
#endif
			errno = ENOMEM;
		}
	} else {
		if (malloc_init())
			ret = NULL;
		else
			ret = imalloc(size);

		if (ret == NULL) {
#ifdef MALLOC_XMALLOC
			if (opt_xmalloc) {
				_malloc_message(_getprogname(),
				    ": (malloc) Error in realloc(): out of "
				    "memory\n", "", "");
				abort();
			}
#endif
			errno = ENOMEM;
		}
	}

#ifdef MALLOC_SYSV
RETURN:
#endif
	UTRACE(ptr, size, ret);
	return (ret);
}

ZONE_INLINE
void
free(void *ptr)
{
	size_t offset;
	
	UTRACE(ptr, 0, 0);

	/*
	 * A version of idalloc that checks for NULL pointer but only for
	 * huge allocations assuming that CHUNK_ADDR2OFFSET(NULL) == 0.
	 */
	assert(CHUNK_ADDR2OFFSET(NULL) == 0);
	offset = CHUNK_ADDR2OFFSET(ptr);
	if (offset != 0)
		arena_dalloc(ptr, offset);
	else if (ptr != NULL)
		huge_dalloc(ptr);
}

/*
 * End malloc(3)-compatible functions.
 */
/******************************************************************************/
/*
 * Begin non-standard functions.
 */
#ifdef MOZ_MEMORY_ANDROID
size_t
malloc_usable_size(void *ptr)
#else
size_t
malloc_usable_size(const void *ptr)
#endif
{

#ifdef MALLOC_VALIDATE
	return (isalloc_validate(ptr));
#else
	assert(ptr != NULL);

	return (isalloc(ptr));
#endif
}

void
jemalloc_stats(jemalloc_stats_t *stats)
{
	size_t i;

	assert(stats != NULL);

	/*
	 * Gather runtime settings.
	 */
	stats->opt_abort = opt_abort;
	stats->opt_junk =
#ifdef MALLOC_FILL
	    opt_junk ? true :
#endif
	    false;
	stats->opt_utrace =
#ifdef MALLOC_UTRACE
	    opt_utrace ? true :
#endif
	    false;
	stats->opt_sysv =
#ifdef MALLOC_SYSV
	    opt_sysv ? true :
#endif
	    false;
	stats->opt_xmalloc =
#ifdef MALLOC_XMALLOC
	    opt_xmalloc ? true :
#endif
	    false;
	stats->opt_zero =
#ifdef MALLOC_FILL
	    opt_zero ? true :
#endif
	    false;
	stats->narenas = narenas;
	stats->balance_threshold =
#ifdef MALLOC_BALANCE
	    opt_balance_threshold
#else
	    SIZE_T_MAX
#endif
	    ;
	stats->quantum = quantum;
	stats->small_max = small_max;
	stats->large_max = arena_maxclass;
	stats->chunksize = chunksize;
	stats->dirty_max = opt_dirty_max;

	/*
	 * Gather current memory usage statistics.
	 */
	stats->mapped = 0;
	stats->committed = 0;
	stats->allocated = 0;
	stats->dirty = 0;

	/* Get huge mapped/allocated. */
	malloc_mutex_lock(&huge_mtx);
	stats->mapped += stats_chunks.curchunks * chunksize;
#ifdef MALLOC_DECOMMIT
	stats->committed += huge_allocated;
#endif
	stats->allocated += huge_allocated;
	malloc_mutex_unlock(&huge_mtx);

	/* Get base mapped. */
	malloc_mutex_lock(&base_mtx);
	stats->mapped += base_mapped;
#ifdef MALLOC_DECOMMIT
	assert(base_committed <= base_mapped);
	stats->committed += base_committed;
#endif
	malloc_mutex_unlock(&base_mtx);

	/* Iterate over arenas and their chunks. */
	for (i = 0; i < narenas; i++) {
		arena_t *arena = arenas[i];
		if (arena != NULL) {
			arena_chunk_t *chunk;

			malloc_spin_lock(&arena->lock);
			stats->allocated += arena->stats.allocated_small;
			stats->allocated += arena->stats.allocated_large;
#ifdef MALLOC_DECOMMIT
			stats->committed += (arena->stats.committed <<
			    pagesize_2pow);
#endif
			stats->dirty += (arena->ndirty << pagesize_2pow);
			malloc_spin_unlock(&arena->lock);
		}
	}

#ifndef MALLOC_DECOMMIT
	stats->committed = stats->mapped;
#endif
	assert(stats->mapped >= stats->committed);
	assert(stats->committed >= stats->allocated);
}

#ifdef MOZ_MEMORY_WINDOWS
void*
_recalloc(void *ptr, size_t count, size_t size)
{
	size_t oldsize = (ptr != NULL) ? isalloc(ptr) : 0;
	size_t newsize = count * size;

	/*
	 * In order for all trailing bytes to be zeroed, the caller needs to
	 * use calloc(), followed by recalloc().  However, the current calloc()
	 * implementation only zeros the bytes requested, so if recalloc() is
	 * to work 100% correctly, calloc() will need to change to zero
	 * trailing bytes.
	 */

	ptr = realloc(ptr, newsize);
	if (ptr != NULL && oldsize < newsize) {
		memset((void *)((uintptr_t)ptr + oldsize), 0, newsize -
		    oldsize);
	}

	return ptr;
}

/*
 * This impl of _expand doesn't ever actually expand or shrink blocks: it
 * simply replies that you may continue using a shrunk block.
 */
void*
_expand(void *ptr, size_t newsize)
{
	if (isalloc(ptr) >= newsize)
		return ptr;

	return NULL;
}

size_t
_msize(const void *ptr)
{

	return malloc_usable_size(ptr);
}
#endif

/*
 * End non-standard functions.
 */
/******************************************************************************/
/*
 * Begin library-private functions, used by threading libraries for protection
 * of malloc during fork().  These functions are only called if the program is
 * running in threaded mode, so there is no need to check whether the program
 * is threaded here.
 */

void
_malloc_prefork(void)
{
	unsigned i;

	/* Acquire all mutexes in a safe order. */

	malloc_spin_lock(&arenas_lock);
	for (i = 0; i < narenas; i++) {
		if (arenas[i] != NULL)
			malloc_spin_lock(&arenas[i]->lock);
	}

	malloc_mutex_lock(&base_mtx);

	malloc_mutex_lock(&huge_mtx);
}

void
_malloc_postfork(void)
{
	unsigned i;

	/* Release all mutexes, now that fork() has completed. */

	malloc_mutex_unlock(&huge_mtx);

	malloc_mutex_unlock(&base_mtx);

	for (i = 0; i < narenas; i++) {
		if (arenas[i] != NULL)
			malloc_spin_unlock(&arenas[i]->lock);
	}
	malloc_spin_unlock(&arenas_lock);
}

/*
 * End library-private functions.
 */
/******************************************************************************/

#ifdef HAVE_DLOPEN
#  include <dlfcn.h>
#endif

#ifdef MOZ_MEMORY_DARWIN
static malloc_zone_t zone;
static struct malloc_introspection_t zone_introspect;

static size_t
zone_size(malloc_zone_t *zone, void *ptr)
{

	/*
	 * There appear to be places within Darwin (such as setenv(3)) that
	 * cause calls to this function with pointers that *no* zone owns.  If
	 * we knew that all pointers were owned by *some* zone, we could split
	 * our zone into two parts, and use one as the default allocator and
	 * the other as the default deallocator/reallocator.  Since that will
	 * not work in practice, we must check all pointers to assure that they
	 * reside within a mapped chunk before determining size.
	 */
	return (isalloc_validate(ptr));
}

static void *
zone_malloc(malloc_zone_t *zone, size_t size)
{

	return (malloc(size));
}

static void *
zone_calloc(malloc_zone_t *zone, size_t num, size_t size)
{

	return (calloc(num, size));
}

static void *
zone_valloc(malloc_zone_t *zone, size_t size)
{
	void *ret = NULL; /* Assignment avoids useless compiler warning. */

	posix_memalign(&ret, pagesize, size);

	return (ret);
}

static void
zone_free(malloc_zone_t *zone, void *ptr)
{

	free(ptr);
}

static void *
zone_realloc(malloc_zone_t *zone, void *ptr, size_t size)
{

	return (realloc(ptr, size));
}

static void *
zone_destroy(malloc_zone_t *zone)
{

	/* This function should never be called. */
	assert(false);
	return (NULL);
}

static size_t
zone_good_size(malloc_zone_t *zone, size_t size)
{
	size_t ret;
	void *p;

	/*
	 * Actually create an object of the appropriate size, then find out
	 * how large it could have been without moving up to the next size
	 * class.
	 */
	p = malloc(size);
	if (p != NULL) {
		ret = isalloc(p);
		free(p);
	} else
		ret = size;

	return (ret);
}

static void
zone_force_lock(malloc_zone_t *zone)
{

	_malloc_prefork();
}

static void
zone_force_unlock(malloc_zone_t *zone)
{

	_malloc_postfork();
}

static malloc_zone_t *
create_zone(void)
{

	assert(malloc_initialized);

	zone.size = (void *)zone_size;
	zone.malloc = (void *)zone_malloc;
	zone.calloc = (void *)zone_calloc;
	zone.valloc = (void *)zone_valloc;
	zone.free = (void *)zone_free;
	zone.realloc = (void *)zone_realloc;
	zone.destroy = (void *)zone_destroy;
	zone.zone_name = "jemalloc_zone";
	zone.batch_malloc = NULL;
	zone.batch_free = NULL;
	zone.introspect = &zone_introspect;

	zone_introspect.enumerator = NULL;
	zone_introspect.good_size = (void *)zone_good_size;
	zone_introspect.check = NULL;
	zone_introspect.print = NULL;
	zone_introspect.log = NULL;
	zone_introspect.force_lock = (void *)zone_force_lock;
	zone_introspect.force_unlock = (void *)zone_force_unlock;
	zone_introspect.statistics = NULL;

	return (&zone);
}

__attribute__((constructor))
void
jemalloc_darwin_init(void)
{
	extern unsigned malloc_num_zones;
	extern malloc_zone_t **malloc_zones;

	if (malloc_init_hard())
		abort();

	/*
	 * The following code is *not* thread-safe, so it's critical that
	 * initialization be manually triggered.
	 */

	/* Register the custom zones. */
	malloc_zone_register(create_zone());
	assert(malloc_zones[malloc_num_zones - 1] == &zone);

	/*
	 * Shift malloc_zones around so that zone is first, which makes it the
	 * default zone.
	 */
	assert(malloc_num_zones > 1);
	memmove(&malloc_zones[1], &malloc_zones[0],
		sizeof(malloc_zone_t *) * (malloc_num_zones - 1));
	malloc_zones[0] = &zone;
}

#elif defined(__GLIBC__) && !defined(__UCLIBC__)
/*
 * glibc provides the RTLD_DEEPBIND flag for dlopen which can make it possible
 * to inconsistently reference libc's malloc(3)-compatible functions
 * (bug 493541).
 *
 * These definitions interpose hooks in glibc.  The functions are actually
 * passed an extra argument for the caller return address, which will be
 * ignored.
 */
#ifndef WRAP_MALLOC
void (*__free_hook)(void *ptr) = free;
void *(*__malloc_hook)(size_t size) = malloc;
void *(*__realloc_hook)(void *ptr, size_t size) = realloc;
void *(*__memalign_hook)(size_t alignment, size_t size) = MEMALIGN;
#endif

#elif defined(RTLD_DEEPBIND)
/*
 * XXX On systems that support RTLD_GROUP or DF_1_GROUP, do their
 * implementations permit similar inconsistencies?  Should STV_SINGLETON
 * visibility be used for interposition where available?
 */
#  error "Interposing malloc is unsafe on this system without libc malloc hooks."
#endif