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jemalloc.c
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jemalloc.c
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/* -*- 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
#include <sys/types.h>
#include <errno.h>
#include <stdlib.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#ifdef MOZ_MEMORY_WINDOWS
/* XXXkhuey switch to not patching the CRT for jemalloc all the time */
/* We use ifndef NEW_STYLE here because when we're build as part of the CRT
we don't have access to AC_DEFINEs */
#ifndef WIN32_NEW_STYLE_JEMALLOC
#include <cruntime.h>
#include <internal.h>
#else
/* Some defines from the CRT internal headers that we need here. */
#define _CRT_SPINCOUNT 5000
#define __crtInitCritSecAndSpinCount InitializeCriticalSectionAndSpinCount
#endif
#include <io.h>
#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
#define _pthread_self() __threadid()
#define issetugid() 0
/* 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);
}
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
#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.
*/
#define CHUNK_2POW_DEFAULT 20
/* 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 |