gecko-dev/memory/mozjemalloc/mozjemalloc.cpp

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/* -*- Mode: C; tab-width: 8; c-basic-offset: 8; indent-tabs-mode: t -*- */
/* vim:set softtabstop=8 shiftwidth=8 noet: */
/*-
* 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 |
* | | ... |
* |=====================================|
*
* NOTE: Due to Mozilla bug 691003, we cannot reserve less than one word for an
* allocation on Linux or Mac. So on 32-bit *nix, the smallest bucket size is
* 4 bytes, and on 64-bit, the smallest bucket size is 8 bytes.
*
* 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.
*
*******************************************************************************
*/
#include "mozmemory_wrap.h"
#include "mozilla/Sprintf.h"
#ifdef MOZ_MEMORY_ANDROID
#define NO_TLS
#endif
/*
* On Linux, we use madvise(MADV_DONTNEED) to release memory back to the
* operating system. If we release 1MB of live pages with MADV_DONTNEED, our
* RSS will decrease by 1MB (almost) immediately.
*
* On Mac, we use madvise(MADV_FREE). Unlike MADV_DONTNEED on Linux, MADV_FREE
* on Mac doesn't cause the OS to release the specified pages immediately; the
* OS keeps them in our process until the machine comes under memory pressure.
*
* It's therefore difficult to measure the process's RSS on Mac, since, in the
* absence of memory pressure, the contribution from the heap to RSS will not
* decrease due to our madvise calls.
*
* We therefore define MALLOC_DOUBLE_PURGE on Mac. This causes jemalloc to
* track which pages have been MADV_FREE'd. You can then call
* jemalloc_purge_freed_pages(), which will force the OS to release those
* MADV_FREE'd pages, making the process's RSS reflect its true memory usage.
*
* The jemalloc_purge_freed_pages definition in memory/build/mozmemory.h needs
* to be adjusted if MALLOC_DOUBLE_PURGE is ever enabled on Linux.
*/
#ifdef MOZ_MEMORY_DARWIN
#define MALLOC_DOUBLE_PURGE
#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
/* Some defines from the CRT internal headers that we need here. */
#define _CRT_SPINCOUNT 5000
#include <io.h>
#include <windows.h>
#include <intrin.h>
#include <algorithm>
#define SIZE_T_MAX SIZE_MAX
#define STDERR_FILENO 2
#ifndef NO_TLS
static unsigned long tlsIndex = 0xffffffff;
#endif
/* 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 nullptr;
}
#if defined(_WIN64)
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
#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>
#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>
#include <errno.h>
#include <limits.h>
#ifndef SIZE_T_MAX
# define SIZE_T_MAX SIZE_MAX
#endif
#include <pthread.h>
#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
#endif
#include "mozjemalloc_types.h"
#include "linkedlist.h"
extern "C" void moz_abort();
/* 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;
long prot;
long flags;
long fd;
off_t offset;
} args = { addr, length, prot, flags, fd, offset };
return (void *) syscall(SYS_mmap, &args);
#else
#if defined(MOZ_MEMORY_ANDROID) && defined(__aarch64__) && defined(SYS_mmap2)
/* Android NDK defines SYS_mmap2 for AArch64 despite it not supporting mmap2 */
#undef SYS_mmap2
#endif
#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 pthread_key_t tlsIndex;
#endif
#ifdef MOZ_MEMORY_WINDOWS
/* MSVC++ does not support C99 variable-length arrays. */
# define RB_NO_C99_VARARRAYS
#endif
#include "rb.h"
#ifdef MOZ_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 non-tiny allocations is 2^QUANTUM_2POW_MIN bytes. */
# define QUANTUM_2POW_MIN 4
#if defined(_WIN64) || defined(__LP64__)
# define SIZEOF_PTR_2POW 3
#else
# define SIZEOF_PTR_2POW 2
#endif
#define PIC
#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
/*
* 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 << 8)
/*
* 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. On Windows the smallest allocation size
* must be 8 bytes on 32-bit, 16 bytes on 64-bit. On Linux and Mac, even
* malloc(1) must reserve a word's worth of memory (see Mozilla bug 691003).
*/
#ifdef MOZ_MEMORY_WINDOWS
#define TINY_MIN_2POW (sizeof(void*) == 8 ? 4 : 3)
#else
#define TINY_MIN_2POW (sizeof(void*) == 8 ? 3 : 2)
#endif
/*
* 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
/******************************************************************************/
/* MALLOC_DECOMMIT and MALLOC_DOUBLE_PURGE are mutually exclusive. */
#if defined(MALLOC_DECOMMIT) && defined(MALLOC_DOUBLE_PURGE)
#error MALLOC_DECOMMIT and MALLOC_DOUBLE_PURGE are mutually exclusive.
#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;
#else
typedef pthread_mutex_t malloc_mutex_t;
typedef pthread_mutex_t malloc_spinlock_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;
#else
static malloc_mutex_t init_lock = PTHREAD_MUTEX_INITIALIZER;
#endif
/******************************************************************************/
/*
* Statistics data structures.
*/
typedef struct malloc_bin_stats_s malloc_bin_stats_t;
struct malloc_bin_stats_s {
/* 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;
/* Current number of committed pages. */
size_t committed;
/* Per-size-category statistics. */
size_t allocated_small;
size_t allocated_large;
};
/******************************************************************************/
/*
* Extent data structures.
*/
enum ChunkType {
UNKNOWN_CHUNK,
ZEROED_CHUNK, // chunk only contains zeroes
ARENA_CHUNK, // used to back arena runs created by arena_run_alloc
HUGE_CHUNK, // used to back huge allocations (e.g. huge_malloc)
RECYCLED_CHUNK, // chunk has been stored for future use by chunk_recycle
};
/* 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;
/* What type of chunk is there; used by chunk recycling code. */
ChunkType chunk_type;
};
typedef rb_tree(extent_node_t) extent_tree_t;
/******************************************************************************/
/*
* Radix tree data structures.
*/
/*
* 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. */
};
/******************************************************************************/
/*
* 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):
*
* ???????? ???????? ????---- -mckdzla
*
* ? : 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.
* m : MADV_FREE/MADV_DONTNEED'ed?
* 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;
/* Note that CHUNK_MAP_DECOMMITTED's meaning varies depending on whether
* MALLOC_DECOMMIT and MALLOC_DOUBLE_PURGE are defined.
*
* If MALLOC_DECOMMIT is defined, a page which is CHUNK_MAP_DECOMMITTED must be
* re-committed with pages_commit() before it may be touched. If
* MALLOC_DECOMMIT is defined, MALLOC_DOUBLE_PURGE may not be defined.
*
* If neither MALLOC_DECOMMIT nor MALLOC_DOUBLE_PURGE is defined, pages which
* are madvised (with either MADV_DONTNEED or MADV_FREE) are marked with
* CHUNK_MAP_MADVISED.
*
* Otherwise, if MALLOC_DECOMMIT is not defined and MALLOC_DOUBLE_PURGE is
* defined, then a page which is madvised is marked as CHUNK_MAP_MADVISED.
* When it's finally freed with jemalloc_purge_freed_pages, the page is marked
* as CHUNK_MAP_DECOMMITTED.
*/
#define CHUNK_MAP_MADVISED ((size_t)0x40U)
#define CHUNK_MAP_DECOMMITTED ((size_t)0x20U)
#define CHUNK_MAP_MADVISED_OR_DECOMMITTED (CHUNK_MAP_MADVISED | CHUNK_MAP_DECOMMITTED)
#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;
#ifdef MALLOC_DOUBLE_PURGE
/* If we're double-purging, we maintain a linked list of chunks which
* have pages which have been madvise(MADV_FREE)'d but not explicitly
* purged.
*
* We're currently lazy and don't remove a chunk from this list when
* all its madvised pages are recommitted. */
LinkedList chunks_madvised_elem;
#endif
/* 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 {
#if defined(MOZ_DEBUG) || defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
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;
/* Bin statistics. */
malloc_bin_stats_t stats;
};
struct arena_s {
#if defined(MOZ_DEBUG) || defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
uint32_t magic;
# define ARENA_MAGIC 0x947d3d24
#endif
/* All operations on this arena require that lock be locked. */
malloc_spinlock_t lock;
arena_stats_t stats;
/* Tree of dirty-page-containing chunks this arena manages. */
arena_chunk_tree_t chunks_dirty;
#ifdef MALLOC_DOUBLE_PURGE
/* Head of a linked list of MADV_FREE'd-page-containing chunks this
* arena manages. */
LinkedList chunks_madvised;
#endif
/*
* 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;
/*
* 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.
*/
/*
* When MALLOC_STATIC_SIZES is defined most of the parameters
* controlling the malloc behavior are defined as compile-time constants
* for best performance and cannot be altered at runtime.
*/
#if !defined(__ia64__) && !defined(__sparc__) && !defined(__mips__) && !defined(__aarch64__)
#define MALLOC_STATIC_SIZES 1
#endif
#ifdef MALLOC_STATIC_SIZES
/*
* VM page size. It must divide the runtime CPU page size or the code
* will abort.
* Platform specific page size conditions copied from js/public/HeapAPI.h
*/
#if (defined(SOLARIS) || defined(__FreeBSD__)) && \
(defined(__sparc) || defined(__sparcv9) || defined(__ia64))
#define pagesize_2pow ((size_t) 13)
#elif defined(__powerpc64__)
#define pagesize_2pow ((size_t) 16)
#else
#define pagesize_2pow ((size_t) 12)
#endif
#define pagesize ((size_t) 1 << pagesize_2pow)
#define pagesize_mask (pagesize - 1)
/* Various quantum-related settings. */
#define QUANTUM_DEFAULT ((size_t) 1 << QUANTUM_2POW_MIN)
static const size_t quantum = QUANTUM_DEFAULT;
static const size_t quantum_mask = QUANTUM_DEFAULT - 1;
/* Various bin-related settings. */
static const size_t small_min = (QUANTUM_DEFAULT >> 1) + 1;
static const size_t small_max = (size_t) SMALL_MAX_DEFAULT;
/* Max size class for bins. */
static const size_t bin_maxclass = pagesize >> 1;
/* Number of (2^n)-spaced tiny bins. */
static const unsigned ntbins = (unsigned)
(QUANTUM_2POW_MIN - TINY_MIN_2POW);
/* Number of quantum-spaced bins. */
static const unsigned nqbins = (unsigned)
(SMALL_MAX_DEFAULT >> QUANTUM_2POW_MIN);
/* Number of (2^n)-spaced sub-page bins. */
static const unsigned nsbins = (unsigned)
(pagesize_2pow -
SMALL_MAX_2POW_DEFAULT - 1);
#else /* !MALLOC_STATIC_SIZES */
/* 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). */
#endif
/* Various chunk-related settings. */
/*
* 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.
*/
#define calculate_arena_header_size() \
(sizeof(arena_chunk_t) + sizeof(arena_chunk_map_t) * (chunk_npages - 1))
#define calculate_arena_header_pages() \
((calculate_arena_header_size() >> pagesize_2pow) + \
((calculate_arena_header_size() & pagesize_mask) ? 1 : 0))
/* Max size class for arenas. */
#define calculate_arena_maxclass() \
(chunksize - (arena_chunk_header_npages << pagesize_2pow))
/*
* Recycle at most 128 chunks. With 1 MiB chunks, this means we retain at most
* 6.25% of the process address space on a 32-bit OS for later use.
*/
#define CHUNK_RECYCLE_LIMIT 128
#ifdef MALLOC_STATIC_SIZES
#define CHUNKSIZE_DEFAULT ((size_t) 1 << CHUNK_2POW_DEFAULT)
static const size_t chunksize = CHUNKSIZE_DEFAULT;
static const size_t chunksize_mask =CHUNKSIZE_DEFAULT - 1;
static const size_t chunk_npages = CHUNKSIZE_DEFAULT >> pagesize_2pow;
#define arena_chunk_header_npages calculate_arena_header_pages()
#define arena_maxclass calculate_arena_maxclass()
static const size_t recycle_limit = CHUNK_RECYCLE_LIMIT * CHUNKSIZE_DEFAULT;
#else
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. */
static size_t recycle_limit;
#endif
/* The current amount of recycled bytes, updated atomically. */
static size_t recycled_size;
/********/
/*
* Chunks.
*/
static malloc_rtree_t *chunk_rtree;
/* Protects chunk-related data structures. */
static malloc_mutex_t chunks_mtx;
/*
* Trees of chunks that were previously allocated (trees differ only in node
* ordering). These are used when allocating chunks, in an attempt to re-use
* address space. Depending on function, different tree orderings are needed,
* which is why there are two trees with the same contents.
*/
static extent_tree_t chunks_szad_mmap;
static extent_tree_t chunks_ad_mmap;
/* Protects huge allocation-related data structures. */
static malloc_mutex_t huge_mtx;
/* Tree of chunks that are stand-alone huge allocations. */
static extent_tree_t huge;
/* Huge allocation statistics. */
static uint64_t huge_nmalloc;
static uint64_t huge_ndalloc;
static size_t huge_allocated;
static size_t huge_mapped;
/****************************/
/*
* 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;
static void *base_next_decommitted;
static void *base_past_addr; /* Addr immediately past base_pages. */
static extent_node_t *base_nodes;
static malloc_mutex_t base_mtx;
static size_t base_mapped;
static size_t base_committed;
/********/
/*
* 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;
static malloc_spinlock_t arenas_lock; /* Protects arenas initialization. */
#ifndef NO_TLS
/*
* Map of pthread_self() --> arenas[???], used for selecting an arena to use
* for allocations.
*/
#if !defined(MOZ_MEMORY_WINDOWS) && !defined(MOZ_MEMORY_DARWIN)
static __thread arena_t *arenas_map;
#endif
#endif
/*******************************/
/*
* Runtime configuration options.
*/
const uint8_t kAllocJunk = 0xe4;
const uint8_t kAllocPoison = 0xe5;
#ifdef MOZ_DEBUG
static bool opt_junk = true;
static bool opt_zero = false;
#else
static const bool opt_junk = false;
static const bool opt_zero = false;
#endif
static size_t opt_dirty_max = DIRTY_MAX_DEFAULT;
#ifdef MALLOC_STATIC_SIZES
#define opt_quantum_2pow QUANTUM_2POW_MIN
#define opt_small_max_2pow SMALL_MAX_2POW_DEFAULT
#define opt_chunk_2pow CHUNK_2POW_DEFAULT
#else
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;
#endif
/******************************************************************************/
/*
* Begin forward declarations.
*/
static void *chunk_alloc(size_t size, size_t alignment, bool base, bool *zeroed=nullptr);
static void chunk_dealloc(void *chunk, size_t size, ChunkType chunk_type);
static void chunk_ensure_zero(void* ptr, size_t size, bool zeroed);
static arena_t *arenas_extend();
static void *huge_malloc(size_t size, bool zero);
static void *huge_palloc(size_t size, size_t alignment, bool zero);
static void *huge_ralloc(void *ptr, size_t size, size_t oldsize);
static void huge_dalloc(void *ptr);
#ifdef MOZ_MEMORY_WINDOWS
extern "C"
#else
static
#endif
bool malloc_init_hard(void);
#ifdef MOZ_MEMORY_DARWIN
#define FORK_HOOK extern "C"
#else
#define FORK_HOOK static
#endif
FORK_HOOK void _malloc_prefork(void);
FORK_HOOK void _malloc_postfork_parent(void);
FORK_HOOK void _malloc_postfork_child(void);
/*
* End forward declarations.
*/
/******************************************************************************/
static inline size_t
load_acquire_z(size_t *p)
{
volatile size_t result = *p;
# ifdef MOZ_MEMORY_WINDOWS
/*
* We use InterlockedExchange with a dummy value to insert a memory
* barrier. This has been confirmed to generate the right instruction
* and is also used by MinGW.
*/
volatile long dummy = 0;
InterlockedExchange(&dummy, 1);
# else
__sync_synchronize();
# endif
return result;
}
static void
_malloc_message(const char *p)
{
#if !defined(MOZ_MEMORY_WINDOWS)
#define _write write
#endif
// Pretend to check _write() errors to suppress gcc warnings about
// warn_unused_result annotations in some versions of glibc headers.
if (_write(STDERR_FILENO, p, (unsigned int) strlen(p)) < 0)
return;
}
template <typename... Args>
static void
_malloc_message(const char *p, Args... args)
{
_malloc_message(p);
_malloc_message(args...);
}
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/TaggedAnonymousMemory.h"
// Note: MozTaggedAnonymousMmap() could call an LD_PRELOADed mmap
// instead of the one defined here; use only MozTagAnonymousMemory().
#ifdef MOZ_MEMORY_ANDROID
// Android's pthread.h does not declare pthread_atfork() until SDK 21.
extern "C" MOZ_EXPORT
int pthread_atfork(void (*)(void), void (*)(void), void(*)(void));
#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_WINDOWS)
if (!InitializeCriticalSectionAndSpinCount(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);
#else
if (pthread_mutex_init(mutex, nullptr) != 0)
return (true);
#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);
#else
pthread_mutex_lock(mutex);
#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);
#else
pthread_mutex_unlock(mutex);
#endif
}
#if (defined(__GNUC__))
__attribute__((unused))
# endif
static bool
malloc_spin_init(malloc_spinlock_t *lock)
{
#if defined(MOZ_MEMORY_WINDOWS)
if (!InitializeCriticalSectionAndSpinCount(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);
#else
if (pthread_mutex_init(lock, nullptr) != 0)
return (true);
#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);
#else
pthread_mutex_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);
#else
pthread_mutex_unlock(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_DARWIN)
# define malloc_spin_init malloc_mutex_init
# define malloc_spin_lock malloc_mutex_lock
# define malloc_spin_unlock malloc_mutex_unlock
#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);
}
static inline const char *
_getprogname(void)
{
return ("<jemalloc>");
}
/******************************************************************************/
static inline void
pages_decommit(void *addr, size_t size)
{
#ifdef MOZ_MEMORY_WINDOWS
/*
* The region starting at addr may have been allocated in multiple calls
* to VirtualAlloc and recycled, so decommitting the entire region in one
* go may not be valid. However, since we allocate at least a chunk at a
* time, we may touch any region in chunksized increments.
*/
size_t pages_size = std::min(size, chunksize -
CHUNK_ADDR2OFFSET((uintptr_t)addr));
while (size > 0) {
if (!VirtualFree(addr, pages_size, MEM_DECOMMIT))
moz_abort();
addr = (void *)((uintptr_t)addr + pages_size);
size -= pages_size;
pages_size = std::min(size, chunksize);
}
#else
if (mmap(addr, size, PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON, -1,
0) == MAP_FAILED)
moz_abort();
MozTagAnonymousMemory(addr, size, "jemalloc-decommitted");
#endif
}
static inline void
pages_commit(void *addr, size_t size)
{
# ifdef MOZ_MEMORY_WINDOWS
/*
* The region starting at addr may have been allocated in multiple calls
* to VirtualAlloc and recycled, so committing the entire region in one
* go may not be valid. However, since we allocate at least a chunk at a
* time, we may touch any region in chunksized increments.
*/
size_t pages_size = std::min(size, chunksize -
CHUNK_ADDR2OFFSET((uintptr_t)addr));
while (size > 0) {
if (!VirtualAlloc(addr, pages_size, MEM_COMMIT, PAGE_READWRITE))
moz_abort();
addr = (void *)((uintptr_t)addr + pages_size);
size -= pages_size;
pages_size = std::min(size, chunksize);
}
# else
if (mmap(addr, size, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE |
MAP_ANON, -1, 0) == MAP_FAILED)
moz_abort();
MozTagAnonymousMemory(addr, size, "jemalloc");
# endif
}
static bool
base_pages_alloc(size_t minsize)
{
size_t csize;
size_t pminsize;
MOZ_ASSERT(minsize != 0);
csize = CHUNK_CEILING(minsize);
base_pages = chunk_alloc(csize, chunksize, true);
if (!base_pages)
return (true);
base_next_addr = base_pages;
base_past_addr = (void *)((uintptr_t)base_pages + csize);
/*
* 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 defined(MALLOC_DECOMMIT)
if (pminsize < csize)
pages_decommit(base_next_decommitted, csize - pminsize);
# endif
base_mapped += csize;
base_committed += pminsize;
return (false);
}
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 nullptr;
}
}
/* Allocate. */
ret = base_next_addr;
base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
/* 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));
# ifdef MALLOC_DECOMMIT
pages_commit(base_next_decommitted, (uintptr_t)pbase_next_addr -
(uintptr_t)base_next_decommitted);
# endif
base_next_decommitted = pbase_next_addr;
base_committed += (uintptr_t)pbase_next_addr -
(uintptr_t)base_next_decommitted;
}
malloc_mutex_unlock(&base_mtx);
return (ret);
}
static void *
base_calloc(size_t number, size_t size)
{
void *ret;
ret = base_alloc(number * size);
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) {
ret = base_nodes;
base_nodes = *(extent_node_t **)ret;
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);
*(extent_node_t **)node = base_nodes;
base_nodes = node;
malloc_mutex_unlock(&base_mtx);
}
/*
* 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
static void *
pages_map(void *addr, size_t size)
{
void *ret = nullptr;
ret = VirtualAlloc(addr, size, MEM_COMMIT | MEM_RESERVE,
PAGE_READWRITE);
return (ret);
}
static void
pages_unmap(void *addr, size_t size)
{
if (VirtualFree(addr, 0, MEM_RELEASE) == 0) {
_malloc_message(_getprogname(),
": (malloc) Error in VirtualFree()\n");
}
}
#else
static void *
pages_map(void *addr, size_t size)
{
void *ret;
#if defined(__ia64__) || (defined(__sparc__) && defined(__arch64__) && defined(__linux__))
/*
* The JS engine assumes that all allocated pointers have their high 17 bits clear,
* which ia64's mmap doesn't support directly. However, we can emulate it by passing
* mmap an "addr" parameter with those bits clear. The mmap will return that address,
* or the nearest available memory above that address, providing a near-guarantee
* that those bits are clear. If they are not, we return nullptr below to indicate
* out-of-memory.
*
* The addr is chosen as 0x0000070000000000, which still allows about 120TB of virtual
* address space.
*
* See Bug 589735 for more information.
*/
bool check_placement = true;
if (!addr) {
addr = (void*)0x0000070000000000;
check_placement = false;
}
#endif
#if defined(__sparc__) && defined(__arch64__) && defined(__linux__)
const uintptr_t start = 0x0000070000000000ULL;
const uintptr_t end = 0x0000800000000000ULL;
/* Copied from js/src/gc/Memory.cpp and adapted for this source */
uintptr_t hint;
void* region = MAP_FAILED;
for (hint = start; region == MAP_FAILED && hint + size <= end; hint += chunksize) {
region = mmap((void*)hint, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (region != MAP_FAILED) {
if (((size_t) region + (size - 1)) & 0xffff800000000000) {
if (munmap(region, size)) {
MOZ_ASSERT(errno == ENOMEM);
}
region = MAP_FAILED;
}
}
}
ret = region;
#else
/*
* We don't use MAP_FIXED here, because it can cause the *replacement*
* of existing mappings, and we only want to create new mappings.
*/
ret = mmap(addr, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON, -1, 0);
MOZ_ASSERT(ret);
#endif
if (ret == MAP_FAILED) {
ret = nullptr;
}
#if defined(__ia64__) || (defined(__sparc__) && defined(__arch64__) && defined(__linux__))
/*
* If the allocated memory doesn't have its upper 17 bits clear, consider it
* as out of memory.
*/
else if ((long long)ret & 0xffff800000000000) {
munmap(ret, size);
ret = nullptr;
}
/* If the caller requested a specific memory location, verify that's what mmap returned. */
else if (check_placement && ret != addr) {
#else
else if (addr && ret != addr) {
#endif
/*
* We succeeded in mapping memory, but not in the right place.
*/
if (munmap(ret, size) == -1) {
char buf[STRERROR_BUF];
if (strerror_r(errno, buf, sizeof(buf)) == 0) {
_malloc_message(_getprogname(),
": (malloc) Error in munmap(): ", buf, "\n");
}
}
ret = nullptr;
}
if (ret) {
MozTagAnonymousMemory(ret, size, "jemalloc");
}
#if defined(__ia64__) || (defined(__sparc__) && defined(__arch64__) && defined(__linux__))
MOZ_ASSERT(!ret || (!check_placement && ret)
|| (check_placement && ret == addr));
#else
MOZ_ASSERT(!ret || (!addr && ret != addr)
|| (addr && ret == addr));
#endif
return (ret);
}
static void
pages_unmap(void *addr, size_t size)
{
if (munmap(addr, size) == -1) {
char buf[STRERROR_BUF];
if (strerror_r(errno, buf, sizeof(buf)) == 0) {
_malloc_message(_getprogname(),
": (malloc) Error in munmap(): ", buf, "\n");
}
}
}
#endif
#ifdef MOZ_MEMORY_DARWIN
#define VM_COPY_MIN (pagesize << 5)
static inline void
pages_copy(void *dest, const void *src, size_t n)
{
MOZ_ASSERT((void *)((uintptr_t)dest & ~pagesize_mask) == dest);
MOZ_ASSERT(n >= VM_COPY_MIN);
MOZ_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);
}
#endif
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++;
MOZ_DIAGNOSTIC_ASSERT(height * bits_per_level >= bits);
ret = (malloc_rtree_t*)base_calloc(1, sizeof(malloc_rtree_t) +
(sizeof(unsigned) * (height - 1)));
if (!ret)
return nullptr;
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) {
/*
* We leak the rtree here, since there's no generic base
* deallocation.
*/
return nullptr;
}
return (ret);
}
#define MALLOC_RTREE_GET_GENERATE(f) \
/* The least significant bits of the key are ignored. */ \
static inline void * \
f(malloc_rtree_t *rtree, uintptr_t key) \
{ \
void *ret; \
uintptr_t subkey; \
unsigned i, lshift, height, bits; \
void **node, **child; \
\
MALLOC_RTREE_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) { \
MALLOC_RTREE_UNLOCK(&rtree->lock); \
return nullptr; \
} \
} \
\
/* \
* 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_RTREE_UNLOCK(&rtree->lock); \
\
MALLOC_RTREE_GET_VALIDATE \
return (ret); \
}
#ifdef MOZ_DEBUG
# define MALLOC_RTREE_LOCK(l) malloc_spin_lock(l)
# define MALLOC_RTREE_UNLOCK(l) malloc_spin_unlock(l)
# define MALLOC_RTREE_GET_VALIDATE
MALLOC_RTREE_GET_GENERATE(malloc_rtree_get_locked)
# undef MALLOC_RTREE_LOCK
# undef MALLOC_RTREE_UNLOCK
# undef MALLOC_RTREE_GET_VALIDATE
#endif
#define MALLOC_RTREE_LOCK(l)
#define MALLOC_RTREE_UNLOCK(l)
#ifdef MOZ_DEBUG
/*
* Suppose that it were possible for a jemalloc-allocated chunk to be
* munmap()ped, followed by a different allocator in another thread re-using
* overlapping virtual memory, all without invalidating the cached rtree
* value. The result would be a false positive (the rtree would claim that
* jemalloc owns memory that it had actually discarded). I don't think this
* scenario is possible, but the following assertion is a prudent sanity
* check.
*/
# define MALLOC_RTREE_GET_VALIDATE \
MOZ_ASSERT(malloc_rtree_get_locked(rtree, key) == ret);
#else
# define MALLOC_RTREE_GET_VALIDATE
#endif
MALLOC_RTREE_GET_GENERATE(malloc_rtree_get)
#undef MALLOC_RTREE_LOCK
#undef MALLOC_RTREE_UNLOCK
#undef MALLOC_RTREE_GET_VALIDATE
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) {
child = (void**)base_calloc(1, sizeof(void *) <<
rtree->level2bits[i+1]);
if (!child) {
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);
}
/* pages_trim, chunk_alloc_mmap_slow and chunk_alloc_mmap were cherry-picked
* from upstream jemalloc 3.4.1 to fix Mozilla bug 956501. */
/* Return the offset between a and the nearest aligned address at or below a. */
#define ALIGNMENT_ADDR2OFFSET(a, alignment) \
((size_t)((uintptr_t)(a) & (alignment - 1)))
/* Return the smallest alignment multiple that is >= s. */
#define ALIGNMENT_CEILING(s, alignment) \
(((s) + (alignment - 1)) & (~(alignment - 1)))
static void *
pages_trim(void *addr, size_t alloc_size, size_t leadsize, size_t size)
{
void *ret = (void *)((uintptr_t)addr + leadsize);
MOZ_ASSERT(alloc_size >= leadsize + size);
#ifdef MOZ_MEMORY_WINDOWS
{
void *new_addr;
pages_unmap(addr, alloc_size);
new_addr = pages_map(ret, size);
if (new_addr == ret)
return (ret);
if (new_addr)
pages_unmap(new_addr, size);
return nullptr;
}
#else
{
size_t trailsize = alloc_size - leadsize - size;
if (leadsize != 0)
pages_unmap(addr, leadsize);
if (trailsize != 0)
pages_unmap((void *)((uintptr_t)ret + size), trailsize);
return (ret);
}
#endif
}
static void *
chunk_alloc_mmap_slow(size_t size, size_t alignment)
{
void *ret, *pages;
size_t alloc_size, leadsize;
alloc_size = size + alignment - pagesize;
/* Beware size_t wrap-around. */
if (alloc_size < size)
return nullptr;
do {
pages = pages_map(nullptr, alloc_size);
if (!pages)
return nullptr;
leadsize = ALIGNMENT_CEILING((uintptr_t)pages, alignment) -
(uintptr_t)pages;
ret = pages_trim(pages, alloc_size, leadsize, size);
} while (!ret);
MOZ_ASSERT(ret);
return (ret);
}
static void *
chunk_alloc_mmap(size_t size, size_t alignment)
{
void *ret;
size_t offset;
/*
* Ideally, there would be a way to specify alignment to mmap() (like
* NetBSD has), but in the absence of such a feature, we have to work
* hard to efficiently create aligned mappings. The reliable, but
* slow method is to create a mapping that is over-sized, then trim the
* excess. However, that always results in one or two calls to
* pages_unmap().
*
* Optimistically try mapping precisely the right amount before falling
* back to the slow method, with the expectation that the optimistic
* approach works most of the time.
*/
ret = pages_map(nullptr, size);
if (!ret)
return nullptr;
offset = ALIGNMENT_ADDR2OFFSET(ret, alignment);
if (offset != 0) {
pages_unmap(ret, size);
return (chunk_alloc_mmap_slow(size, alignment));
}
MOZ_ASSERT(ret);
return (ret);
}
/* Purge and release the pages in the chunk of length `length` at `addr` to
* the OS.
* Returns whether the pages are guaranteed to be full of zeroes when the
* function returns.
* The force_zero argument explicitly requests that the memory is guaranteed
* to be full of zeroes when the function returns.
*/
static bool
pages_purge(void *addr, size_t length, bool force_zero)
{
#ifdef MALLOC_DECOMMIT
pages_decommit(addr, length);
return true;
#else
# ifndef MOZ_MEMORY_LINUX
if (force_zero)
memset(addr, 0, length);
# endif
# ifdef MOZ_MEMORY_WINDOWS
/*
* The region starting at addr may have been allocated in multiple calls
* to VirtualAlloc and recycled, so resetting the entire region in one
* go may not be valid. However, since we allocate at least a chunk at a
* time, we may touch any region in chunksized increments.
*/
size_t pages_size = std::min(length, chunksize -
CHUNK_ADDR2OFFSET((uintptr_t)addr));
while (length > 0) {
VirtualAlloc(addr, pages_size, MEM_RESET, PAGE_READWRITE);
addr = (void *)((uintptr_t)addr + pages_size);
length -= pages_size;
pages_size = std::min(length, chunksize);
}
return force_zero;
# else
# ifdef MOZ_MEMORY_LINUX
# define JEMALLOC_MADV_PURGE MADV_DONTNEED
# define JEMALLOC_MADV_ZEROS true
# else /* FreeBSD and Darwin. */
# define JEMALLOC_MADV_PURGE MADV_FREE
# define JEMALLOC_MADV_ZEROS force_zero
# endif
int err = madvise(addr, length, JEMALLOC_MADV_PURGE);
return JEMALLOC_MADV_ZEROS && err == 0;
# undef JEMALLOC_MADV_PURGE
# undef JEMALLOC_MADV_ZEROS
# endif
#endif
}
static void *
chunk_recycle(extent_tree_t *chunks_szad, extent_tree_t *chunks_ad, size_t size,
size_t alignment, bool base, bool *zeroed)
{
void *ret;
extent_node_t *node;
extent_node_t key;
size_t alloc_size, leadsize, trailsize;
ChunkType chunk_type;
if (base) {
/*
* This function may need to call base_node_{,de}alloc(), but
* the current chunk allocation request is on behalf of the
* base allocator. Avoid deadlock (and if that weren't an
* issue, potential for infinite recursion) by returning nullptr.
*/
return nullptr;
}
alloc_size = size + alignment - chunksize;
/* Beware size_t wrap-around. */
if (alloc_size < size)
return nullptr;
key.addr = nullptr;
key.size = alloc_size;
malloc_mutex_lock(&chunks_mtx);
node = extent_tree_szad_nsearch(chunks_szad, &key);
if (!node) {
malloc_mutex_unlock(&chunks_mtx);
return nullptr;
}
leadsize = ALIGNMENT_CEILING((uintptr_t)node->addr, alignment) -
(uintptr_t)node->addr;
MOZ_ASSERT(node->size >= leadsize + size);
trailsize = node->size - leadsize - size;
ret = (void *)((uintptr_t)node->addr + leadsize);
chunk_type = node->chunk_type;
if (zeroed) {
*zeroed = (chunk_type == ZEROED_CHUNK);
}
/* Remove node from the tree. */
extent_tree_szad_remove(chunks_szad, node);
extent_tree_ad_remove(chunks_ad, node);
if (leadsize != 0) {
/* Insert the leading space as a smaller chunk. */
node->size = leadsize;
extent_tree_szad_insert(chunks_szad, node);
extent_tree_ad_insert(chunks_ad, node);
node = nullptr;
}
if (trailsize != 0) {
/* Insert the trailing space as a smaller chunk. */
if (!node) {
/*
* An additional node is required, but
* base_node_alloc() can cause a new base chunk to be
* allocated. Drop chunks_mtx in order to avoid
* deadlock, and if node allocation fails, deallocate
* the result before returning an error.
*/
malloc_mutex_unlock(&chunks_mtx);
node = base_node_alloc();
if (!node) {
chunk_dealloc(ret, size, chunk_type);
return nullptr;
}
malloc_mutex_lock(&chunks_mtx);
}
node->addr = (void *)((uintptr_t)(ret) + size);
node->size = trailsize;
node->chunk_type = chunk_type;
extent_tree_szad_insert(chunks_szad, node);
extent_tree_ad_insert(chunks_ad, node);
node = nullptr;
}
recycled_size -= size;
malloc_mutex_unlock(&chunks_mtx);
if (node)
base_node_dealloc(node);
#ifdef MALLOC_DECOMMIT
pages_commit(ret, size);
// pages_commit is guaranteed to zero the chunk.
if (zeroed) {
*zeroed = true;
}
#endif
return (ret);
}
#ifdef MOZ_MEMORY_WINDOWS
/*
* On Windows, calls to VirtualAlloc and VirtualFree must be matched, making it
* awkward to recycle allocations of varying sizes. Therefore we only allow
* recycling when the size equals the chunksize, unless deallocation is entirely
* disabled.
*/
#define CAN_RECYCLE(size) (size == chunksize)
#else
#define CAN_RECYCLE(size) true
#endif
/* Allocates `size` bytes of system memory aligned for `alignment`.
* `base` indicates whether the memory will be used for the base allocator
* (e.g. base_alloc).
* `zeroed` is an outvalue that returns whether the allocated memory is
* guaranteed to be full of zeroes. It can be omitted when the caller doesn't
* care about the result.
*/
static void *
chunk_alloc(size_t size, size_t alignment, bool base, bool *zeroed)
{
void *ret;
MOZ_ASSERT(size != 0);
MOZ_ASSERT((size & chunksize_mask) == 0);
MOZ_ASSERT(alignment != 0);
MOZ_ASSERT((alignment & chunksize_mask) == 0);
if (CAN_RECYCLE(size)) {
ret = chunk_recycle(&chunks_szad_mmap, &chunks_ad_mmap,
size, alignment, base, zeroed);
if (ret)
goto RETURN;
}
ret = chunk_alloc_mmap(size, alignment);
if (zeroed)
*zeroed = true;
if (ret) {
goto RETURN;
}
/* All strategies for allocation failed. */
ret = nullptr;
RETURN:
if (ret && base == false) {
if (malloc_rtree_set(chunk_rtree, (uintptr_t)ret, ret)) {
chunk_dealloc(ret, size, UNKNOWN_CHUNK);
return nullptr;
}
}
MOZ_ASSERT(CHUNK_ADDR2BASE(ret) == ret);
return (ret);
}
static void
chunk_ensure_zero(void* ptr, size_t size, bool zeroed)
{
if (zeroed == false)
memset(ptr, 0, size);
#ifdef MOZ_DEBUG
else {
size_t i;
size_t *p = (size_t *)(uintptr_t)ret;
for (i = 0; i < size / sizeof(size_t); i++)
MOZ_ASSERT(p[i] == 0);
}
#endif
}
static void
chunk_record(extent_tree_t *chunks_szad, extent_tree_t *chunks_ad, void *chunk,
size_t size, ChunkType chunk_type)
{
extent_node_t *xnode, *node, *prev, *xprev, key;
if (chunk_type != ZEROED_CHUNK) {
if (pages_purge(chunk, size, chunk_type == HUGE_CHUNK)) {
chunk_type = ZEROED_CHUNK;
}
}
/*
* Allocate a node before acquiring chunks_mtx even though it might not
* be needed, because base_node_alloc() may cause a new base chunk to
* be allocated, which could cause deadlock if chunks_mtx were already
* held.
*/
xnode = base_node_alloc();
/* Use xprev to implement conditional deferred deallocation of prev. */
xprev = nullptr;
malloc_mutex_lock(&chunks_mtx);
key.addr = (void *)((uintptr_t)chunk + size);
node = extent_tree_ad_nsearch(chunks_ad, &key);
/* Try to coalesce forward. */
if (node && node->addr == key.addr) {
/*
* Coalesce chunk with the following address range. This does
* not change the position within chunks_ad, so only
* remove/insert from/into chunks_szad.
*/
extent_tree_szad_remove(chunks_szad, node);
node->addr = chunk;
node->size += size;
if (node->chunk_type != chunk_type) {
node->chunk_type = RECYCLED_CHUNK;
}
extent_tree_szad_insert(chunks_szad, node);
} else {
/* Coalescing forward failed, so insert a new node. */
if (!xnode) {
/*
* base_node_alloc() failed, which is an exceedingly
* unlikely failure. Leak chunk; its pages have
* already been purged, so this is only a virtual
* memory leak.
*/
goto label_return;
}
node = xnode;
xnode = nullptr; /* Prevent deallocation below. */
node->addr = chunk;
node->size = size;
node->chunk_type = chunk_type;
extent_tree_ad_insert(chunks_ad, node);
extent_tree_szad_insert(chunks_szad, node);
}
/* Try to coalesce backward. */
prev = extent_tree_ad_prev(chunks_ad, node);
if (prev && (void *)((uintptr_t)prev->addr + prev->size) ==
chunk) {
/*
* Coalesce chunk with the previous address range. This does
* not change the position within chunks_ad, so only
* remove/insert node from/into chunks_szad.
*/
extent_tree_szad_remove(chunks_szad, prev);
extent_tree_ad_remove(chunks_ad, prev);
extent_tree_szad_remove(chunks_szad, node);
node->addr = prev->addr;
node->size += prev->size;
if (node->chunk_type != prev->chunk_type) {
node->chunk_type = RECYCLED_CHUNK;
}
extent_tree_szad_insert(chunks_szad, node);
xprev = prev;
}
recycled_size += size;
label_return:
malloc_mutex_unlock(&chunks_mtx);
/*
* Deallocate xnode and/or xprev after unlocking chunks_mtx in order to
* avoid potential deadlock.
*/
if (xnode)
base_node_dealloc(xnode);
if (xprev)
base_node_dealloc(xprev);
}
static bool
chunk_dalloc_mmap(void *chunk, size_t size)
{
if (CAN_RECYCLE(size) && load_acquire_z(&recycled_size) < recycle_limit)
return true;
pages_unmap(chunk, size);
return false;
}
#undef CAN_RECYCLE
static void
chunk_dealloc(void *chunk, size_t size, ChunkType type)
{
MOZ_ASSERT(chunk);
MOZ_ASSERT(CHUNK_ADDR2BASE(chunk) == chunk);
MOZ_ASSERT(size != 0);
MOZ_ASSERT((size & chunksize_mask) == 0);
malloc_rtree_set(chunk_rtree, (uintptr_t)chunk, nullptr);
if (chunk_dalloc_mmap(chunk, size))
chunk_record(&chunks_szad_mmap, &chunks_ad_mmap, chunk, size, type);
}
/*
* End chunk management functions.
*/
/******************************************************************************/
/*
* Begin arena.
*/
static inline arena_t *
thread_local_arena(bool enabled)
{
#ifndef NO_TLS
arena_t *arena;
if (enabled) {
/* The arena will essentially be leaked if this function is
* called with `false`, but it doesn't matter at the moment.
* because in practice nothing actually calls this function
* with `false`, except maybe at shutdown. */
arena = arenas_extend();
} else {
malloc_spin_lock(&arenas_lock);
arena = arenas[0];
malloc_spin_unlock(&arenas_lock);
}
#ifdef MOZ_MEMORY_WINDOWS
TlsSetValue(tlsIndex, arena);
#elif defined(MOZ_MEMORY_DARWIN)
pthread_setspecific(tlsIndex, arena);
#else
arenas_map = arena;
#endif
return arena;
#else
return arenas[0];
#endif
}
MOZ_JEMALLOC_API void
jemalloc_thread_local_arena_impl(bool enabled)
{
thread_local_arena(enabled);
}
/*
* Choose an arena based on a per-thread value.
*/
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
# ifdef MOZ_MEMORY_WINDOWS
ret = (arena_t*)TlsGetValue(tlsIndex);
# elif defined(MOZ_MEMORY_DARWIN)
ret = (arena_t*)pthread_getspecific(tlsIndex);
# else
ret = arenas_map;
# endif
if (!ret) {
ret = thread_local_arena(false);
}
#else
ret = arenas[0];
#endif
MOZ_DIAGNOSTIC_ASSERT(ret);
return (ret);
}
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;
MOZ_ASSERT(a);
MOZ_ASSERT(b);
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;
MOZ_ASSERT(a);
MOZ_ASSERT(b);
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;
MOZ_ASSERT(run->magic == ARENA_RUN_MAGIC);
MOZ_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);
MOZ_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);
MOZ_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. */
MOZ_DIAGNOSTIC_ASSERT(0);
return nullptr;
}
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;
MOZ_ASSERT(run->magic == ARENA_RUN_MAGIC);
MOZ_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;
};
MOZ_DIAGNOSTIC_ASSERT(diff == regind * size);
MOZ_DIAGNOSTIC_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));
MOZ_DIAGNOSTIC_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);
MOZ_ASSERT(need_pages > 0);
MOZ_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++) {
/*
* 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_MADVISED_OR_DECOMMITTED) {
size_t j;
/*
* Advance i+j to just past the index of the last page
* to commit. Clear CHUNK_MAP_DECOMMITTED and
* CHUNK_MAP_MADVISED along the way.
*/
for (j = 0; i + j < need_pages && (chunk->map[run_ind +
i + j].bits & CHUNK_MAP_MADVISED_OR_DECOMMITTED); j++) {
/* DECOMMITTED and MADVISED are mutually exclusive. */
MOZ_ASSERT(!(chunk->map[run_ind + i + j].bits & CHUNK_MAP_DECOMMITTED &&
chunk->map[run_ind + i + j].bits & CHUNK_MAP_MADVISED));
chunk->map[run_ind + i + j].bits &=
~CHUNK_MAP_MADVISED_OR_DECOMMITTED;
}
# ifdef MALLOC_DECOMMIT
pages_commit((void *)((uintptr_t)chunk + ((run_ind + i)
<< pagesize_2pow)), (j << pagesize_2pow));
# endif
arena->stats.committed += j;
# ifndef MALLOC_DECOMMIT
}
# else
} 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) {
memset((void *)((uintptr_t)chunk + ((run_ind
+ i) << pagesize_2pow)), 0, pagesize);
/* 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, bool zeroed)
{
size_t i;
/* WARNING: The following relies on !zeroed meaning "used to be an arena
* chunk".
* When the chunk we're initializating as an arena chunk is zeroed, we
* mark all runs are decommitted and zeroed.
* When it is not, which we can assume means it's a recycled arena chunk,
* all it can contain is an arena chunk header (which we're overwriting),
* and zeroed or poisoned memory (because a recycled arena chunk will
* have been emptied before being recycled). In that case, we can get
* away with reusing the chunk as-is, marking all runs as madvised.
*/
size_t flags = zeroed ? CHUNK_MAP_DECOMMITTED | CHUNK_MAP_ZEROED
: CHUNK_MAP_MADVISED;
arena->stats.mapped += chunksize;
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. */
#ifdef MALLOC_DECOMMIT
arena_run_t *run = (arena_run_t *)((uintptr_t)chunk +
(arena_chunk_header_npages << pagesize_2pow));
#endif
for (i = 0; i < arena_chunk_header_npages; i++)
chunk->map[i].bits = 0;
chunk->map[i].bits = arena_maxclass | flags;
for (i++; i < chunk_npages-1; i++) {
chunk->map[i].bits = flags;
}
chunk->map[chunk_npages-1].bits = arena_maxclass | flags;
#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);
#endif
arena->stats.committed += arena_chunk_header_npages;
/* Insert the run into the runs_avail tree. */
arena_avail_tree_insert(&arena->runs_avail,
&chunk->map[arena_chunk_header_npages]);
#ifdef MALLOC_DOUBLE_PURGE
LinkedList_Init(&chunk->chunks_madvised_elem);
#endif
}
static void
arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
{
if (arena->spare) {
if (arena->spare->ndirty > 0) {
arena_chunk_tree_dirty_remove(
&chunk->arena->chunks_dirty, arena->spare);
arena->ndirty -= arena->spare->ndirty;
arena->stats.committed -= arena->spare->ndirty;
}
#ifdef MALLOC_DOUBLE_PURGE
/* This is safe to do even if arena->spare is not in the list. */
LinkedList_Remove(&arena->spare->chunks_madvised_elem);
#endif
chunk_dealloc((void *)arena->spare, chunksize, ARENA_CHUNK);
arena->stats.mapped -= chunksize;
arena->stats.committed -= arena_chunk_header_npages;
}
/*
* 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;
MOZ_ASSERT(size <= arena_maxclass);
MOZ_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) {
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) {
/* Use the spare. */
arena_chunk_t *chunk = arena->spare;
arena->spare = nullptr;
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.
*/
{
bool zeroed;
arena_chunk_t *chunk = (arena_chunk_t *)
chunk_alloc(chunksize, chunksize, false, &zeroed);
if (!chunk)
return nullptr;
arena_chunk_init(arena, chunk, zeroed);
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, bool all)
{
arena_chunk_t *chunk;
size_t i, npages;
/* If all is set purge all dirty pages. */
size_t dirty_max = all ? 1 : opt_dirty_max;
#ifdef MOZ_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)
MOZ_ASSERT(ndirty == arena->ndirty);
#endif
MOZ_DIAGNOSTIC_ASSERT(all || (arena->ndirty > opt_dirty_max));
/*
* 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 > (dirty_max >> 1)) {
#ifdef MALLOC_DOUBLE_PURGE
bool madvised = false;
#endif
chunk = arena_chunk_tree_dirty_last(&arena->chunks_dirty);
MOZ_DIAGNOSTIC_ASSERT(chunk);
for (i = chunk_npages - 1; chunk->ndirty > 0; i--) {
MOZ_DIAGNOSTIC_ASSERT(i >= arena_chunk_header_npages);
if (chunk->map[i].bits & CHUNK_MAP_DIRTY) {
#ifdef MALLOC_DECOMMIT
const size_t free_operation = CHUNK_MAP_DECOMMITTED;
#else
const size_t free_operation = CHUNK_MAP_MADVISED;
#endif
MOZ_ASSERT((chunk->map[i].bits &
CHUNK_MAP_MADVISED_OR_DECOMMITTED) == 0);
chunk->map[i].bits ^= free_operation | 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--;
MOZ_ASSERT((chunk->map[i].bits &
CHUNK_MAP_MADVISED_OR_DECOMMITTED) == 0);
chunk->map[i].bits ^= free_operation | CHUNK_MAP_DIRTY;
}
chunk->ndirty -= npages;
arena->ndirty -= npages;
#ifdef MALLOC_DECOMMIT
pages_decommit((void *)((uintptr_t)
chunk + (i << pagesize_2pow)),
(npages << pagesize_2pow));
#endif
arena->stats.committed -= npages;
#ifndef MALLOC_DECOMMIT
madvise((void *)((uintptr_t)chunk + (i <<
pagesize_2pow)), (npages << pagesize_2pow),
MADV_FREE);
# ifdef MALLOC_DOUBLE_PURGE
madvised = true;
# endif
#endif
if (arena->ndirty <= (dirty_max >> 1))
break;
}
}
if (chunk->ndirty == 0) {
arena_chunk_tree_dirty_remove(&arena->chunks_dirty,
chunk);
}
#ifdef MALLOC_DOUBLE_PURGE
if (madvised) {
/* The chunk might already be in the list, but this
* makes sure it's at the front. */
LinkedList_Remove(&chunk->chunks_madvised_elem);
LinkedList_InsertHead(&arena->chunks_madvised, &chunk->chunks_madvised_elem);
}
#endif
}
}
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);
MOZ_DIAGNOSTIC_ASSERT(run_ind >= arena_chunk_header_npages);
MOZ_DIAGNOSTIC_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++) {
MOZ_DIAGNOSTIC_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;
MOZ_DIAGNOSTIC_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;
MOZ_DIAGNOSTIC_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, false);
}
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;
MOZ_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;
MOZ_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) {
/* run is guaranteed to have available space. */
arena_run_tree_remove(&bin->runs, mapelm);
run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
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)
return nullptr;
/*
* Don't initialize if a race in arena_run_alloc() allowed an existing
* run to become usable.
*/
if (run == bin->runcur)
return (run);
/* 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;
#if defined(MOZ_DEBUG) || defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
run->magic = ARENA_RUN_MAGIC;
#endif
bin->stats.curruns++;
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;
MOZ_DIAGNOSTIC_ASSERT(run->magic == ARENA_RUN_MAGIC);
MOZ_DIAGNOSTIC_ASSERT(run->nfree > 0);
ret = arena_run_reg_alloc(run, bin);
MOZ_DIAGNOSTIC_ASSERT(ret);
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)
return nullptr;
MOZ_DIAGNOSTIC_ASSERT(bin->runcur->magic == ARENA_RUN_MAGIC);
MOZ_DIAGNOSTIC_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;
MOZ_ASSERT(min_run_size >= pagesize);
MOZ_ASSERT(min_run_size <= arena_maxclass);
/*
* 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
&& RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX
&& (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size);
MOZ_ASSERT(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1))
<= good_reg0_offset);
MOZ_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);
}
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)))];
/*
* 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);
} 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)];
}
MOZ_DIAGNOSTIC_ASSERT(size == bin->reg_size);
malloc_spin_lock(&arena->lock);
if ((run = bin->runcur) && run->nfree > 0)
ret = arena_bin_malloc_easy(arena, bin, run);
else
ret = arena_bin_malloc_hard(arena, bin);
if (!ret) {
malloc_spin_unlock(&arena->lock);
return nullptr;
}
arena->stats.allocated_small += size;
malloc_spin_unlock(&arena->lock);
if (zero == false) {
if (opt_junk)
memset(ret, kAllocJunk, size);
else if (opt_zero)
memset(ret, 0, size);
} 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);
malloc_spin_lock(&arena->lock);
ret = (void *)arena_run_alloc(arena, nullptr, size, true, zero);
if (!ret) {
malloc_spin_unlock(&arena->lock);
return nullptr;
}
arena->stats.allocated_large += size;
malloc_spin_unlock(&arena->lock);
if (zero == false) {
if (opt_junk)
memset(ret, kAllocJunk, size);
else if (opt_zero)
memset(ret, 0, size);
}
return (ret);
}
static inline void *
arena_malloc(arena_t *arena, size_t size, bool zero)
{
MOZ_ASSERT(arena);
MOZ_DIAGNOSTIC_ASSERT(arena->magic == ARENA_MAGIC);
MOZ_ASSERT(size != 0);
MOZ_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)
{
MOZ_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;
MOZ_ASSERT((size & pagesize_mask) == 0);
MOZ_ASSERT((alignment & pagesize_mask) == 0);
malloc_spin_lock(&arena->lock);
ret = (void *)arena_run_alloc(arena, nullptr, alloc_size, true, false);
if (!ret) {
malloc_spin_unlock(&arena->lock);
return nullptr;
}
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ret);
offset = (uintptr_t)ret & (alignment - 1);
MOZ_ASSERT((offset & pagesize_mask) == 0);
MOZ_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. */
MOZ_ASSERT(trailsize < alloc_size);
arena_run_trim_tail(arena, chunk, (arena_run_t*)ret, size + trailsize,
size, false);
}
}
arena->stats.allocated_large += size;
malloc_spin_unlock(&arena->lock);
if (opt_junk)
memset(ret, kAllocJunk, size);
else if (opt_zero)
memset(ret, 0, size);
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 = ALIGNMENT_CEILING(size, 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 nullptr;
}
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 nullptr;
}
/*
* 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(ceil_size, alignment, false);
}
MOZ_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;
MOZ_ASSERT(ptr);
MOZ_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;
MOZ_DIAGNOSTIC_ASSERT((mapbits & CHUNK_MAP_ALLOCATED) != 0);
if ((mapbits & CHUNK_MAP_LARGE) == 0) {
arena_run_t *run = (arena_run_t *)(mapbits & ~pagesize_mask);
MOZ_DIAGNOSTIC_ASSERT(run->magic == ARENA_RUN_MAGIC);
ret = run->bin->reg_size;
} else {
ret = mapbits & ~pagesize_mask;
MOZ_DIAGNOSTIC_ASSERT(ret != 0);
}
return (ret);
}
/*
* Validate ptr before assuming that it points to an allocation. Currently,
* the following validation is performed:
*
* + Check that ptr is not nullptr.
*
* + 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)
return (0);
if (!malloc_rtree_get(chunk_rtree, (uintptr_t)chunk))
return (0);
if (chunk != ptr) {
MOZ_DIAGNOSTIC_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)
ret = node->size;
else
ret = 0;
malloc_mutex_unlock(&huge_mtx);
return (ret);
}
}
static inline size_t
isalloc(const void *ptr)
{
size_t ret;
arena_chunk_t *chunk;
MOZ_ASSERT(ptr);
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (chunk != ptr) {
/* Region. */
MOZ_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 = const_cast<void*>(ptr);
node = extent_tree_ad_search(&huge, &key);
MOZ_DIAGNOSTIC_ASSERT(node);
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);
MOZ_DIAGNOSTIC_ASSERT(run->magic == ARENA_RUN_MAGIC);
bin = run->bin;
size = bin->reg_size;
memset(ptr, kAllocPoison, size);
arena_run_reg_dalloc(run, bin, ptr, size);
run->nfree++;
if (run->nfree == bin->nregs) {
/* Deallocate run. */
if (run == bin->runcur)
bin->runcur = nullptr;
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.
*/
MOZ_DIAGNOSTIC_ASSERT(arena_run_tree_search(&bin->runs, run_mapelm) ==
run_mapelm);
arena_run_tree_remove(&bin->runs, run_mapelm);
}
#if defined(MOZ_DEBUG) || defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
run->magic = 0;
#endif
arena_run_dalloc(arena, run, true);
bin->stats.curruns--;
} 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)
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. */
MOZ_DIAGNOSTIC_ASSERT(!arena_run_tree_search(&bin->runs,
runcur_mapelm));
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];
MOZ_DIAGNOSTIC_ASSERT(arena_run_tree_search(&bin->runs, run_mapelm) ==
nullptr);
arena_run_tree_insert(&bin->runs, run_mapelm);
}
}
arena->stats.allocated_small -= size;
}
static void
arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk, void *ptr)
{
size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >>
pagesize_2pow;
size_t size = chunk->map[pageind].bits & ~pagesize_mask;
memset(ptr, kAllocPoison, size);
arena->stats.allocated_large -= size;
arena_run_dalloc(arena, (arena_run_t *)ptr, true);
}
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;
MOZ_ASSERT(ptr);
MOZ_ASSERT(offset != 0);
MOZ_ASSERT(CHUNK_ADDR2OFFSET(ptr) == offset);
chunk = (arena_chunk_t *) ((uintptr_t)ptr - offset);
arena = chunk->arena;
MOZ_ASSERT(arena);
MOZ_DIAGNOSTIC_ASSERT(arena->magic == ARENA_MAGIC);
malloc_spin_lock(&arena->lock);
pageind = offset >> pagesize_2pow;
mapelm = &chunk->map[pageind];
MOZ_DIAGNOSTIC_ASSERT((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0);
if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
/* Small allocation. */
arena_dalloc_small(arena, chunk, ptr, mapelm);
} else {
/* Large allocation. */
arena_dalloc_large(arena, chunk, ptr);
}
malloc_spin_unlock(&arena->lock);
}
static inline void
idalloc(void *ptr)
{
size_t offset;
MOZ_ASSERT(ptr);
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)
{
MOZ_ASSERT(size < oldsize);
/*
* Shrink the run, and make trailing pages available for other
* allocations.
*/
malloc_spin_lock(&arena->lock);
arena_run_trim_tail(arena, chunk, (arena_run_t *)ptr, oldsize, size,
true);
arena->stats.allocated_large -= oldsize - size;
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;
malloc_spin_lock(&arena->lock);
MOZ_DIAGNOSTIC_ASSERT(oldsize == (chunk->map[pageind].bits & ~pagesize_mask));
/* Try to extend the run. */
MOZ_ASSERT(size > oldsize);
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;
arena->stats.allocated_large += size - oldsize;
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. */
if (size < oldsize) {
memset((void *)((uintptr_t)ptr + size), kAllocPoison, oldsize -
size);
}
return (false);
} else {
arena_chunk_t *chunk;
arena_t *arena;
chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
arena = chunk->arena;
MOZ_DIAGNOSTIC_ASSERT(arena->magic == ARENA_MAGIC);
if (psize < oldsize) {
/* Fill before shrinking in order avoid a race. */
memset((void *)((uintptr_t)ptr + size), kAllocPoison,
oldsize - size);
arena_ralloc_large_shrink(arena, chunk, ptr, psize,
oldsize);
return (false);
} else {
bool ret = arena_ralloc_large_grow(arena, chunk, ptr,
psize, oldsize);
if (ret == false && opt_zero) {
memset((void *)((uintptr_t)ptr + oldsize), 0,
size - oldsize);
}
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) {
MOZ_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)
return nullptr;
/* 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:
if (size < oldsize)
memset((void *)((uintptr_t)ptr + size), kAllocPoison, oldsize - size);
else if (opt_zero && size > oldsize)
memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize);
return (ptr);
}
static inline void *
iralloc(void *ptr, size_t size)
{
size_t oldsize;
MOZ_ASSERT(ptr);
MOZ_ASSERT(size != 0);
oldsize = isalloc(ptr);
if (size <= arena_maxclass)
return (arena_ralloc(ptr, size, oldsize));
else
return (huge_ralloc(ptr, size, oldsize));
}
static bool
arena_new(arena_t *arena)
{
unsigned i;
arena_bin_t *bin;
size_t prev_run_size;
if (malloc_spin_init(&arena->lock))
return (true);
memset(&arena->stats, 0, sizeof(arena_stats_t));
/* Initialize chunks. */
arena_chunk_tree_dirty_new(&arena->chunks_dirty);
#ifdef MALLOC_DOUBLE_PURGE
LinkedList_Init(&arena->chunks_madvised);
#endif
arena->spare = nullptr;
arena->ndirty = 0;
arena_avail_tree_new(&arena->runs_avail);
/* Initialize bins. */
prev_run_size = pagesize;
/* (2^n)-spaced tiny bins. */
for (i = 0; i < ntbins; i++) {
bin = &arena->bins[i];
bin->runcur = nullptr;
arena_run_tree_new(&bin->runs);
bin->reg_size = (1ULL << (TINY_MIN_2POW + i));
prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
}
/* Quantum-spaced bins. */
for (; i < ntbins + nqbins; i++) {
bin = &arena->bins[i];
bin->runcur = nullptr;
arena_run_tree_new(&bin->runs);
bin->reg_size = quantum * (i - ntbins + 1);
prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
}
/* (2^n)-spaced sub-page bins. */
for (; i < ntbins + nqbins + nsbins; i++) {
bin = &arena->bins[i];
bin->runcur = nullptr;
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);
memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
}
#if defined(MOZ_DEBUG) || defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
arena->magic = ARENA_MAGIC;
#endif
return (false);
}
static inline arena_t *
arenas_fallback()
{
/* 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");
return arenas[0];
}
/* Create a new arena and return it. */
static arena_t *
arenas_extend()
{
/*
* The list of arenas is first allocated to contain at most 16 elements,
* and when the limit is reached, the list is grown such that it can
* contain 16 more elements.
*/
const size_t arenas_growth = 16;
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 || arena_new(ret)) {
return arenas_fallback();
}
malloc_spin_lock(&arenas_lock);
/* Allocate and initialize arenas. */
if (narenas % arenas_growth == 0) {
size_t max_arenas = ((narenas + arenas_growth) / arenas_growth) * arenas_growth;
/*
* We're unfortunately leaking the previous allocation ;
* the base allocator doesn't know how to free things
*/
arena_t** new_arenas = (arena_t **)base_alloc(sizeof(arena_t *) * max_arenas);
if (!new_arenas) {
ret = arenas ? arenas_fallback() : nullptr;
malloc_spin_unlock(&arenas_lock);
return (ret);
}
memcpy(new_arenas, arenas, narenas * sizeof(arena_t *));
/*
* Zero the array. In practice, this should always be pre-zeroed,
* since it was just mmap()ed, but let's be sure.
*/
memset(new_arenas + narenas, 0, sizeof(arena_t *) * (max_arenas - narenas));
arenas = new_arenas;
}
arenas[narenas++] = ret;
malloc_spin_unlock(&arenas_lock);
return (ret);
}
/*
* End arena.
*/
/******************************************************************************/
/*
* Begin general internal functions.
*/
static void *
huge_malloc(size_t size, bool zero)
{
return huge_palloc(size, chunksize, zero);
}
static void *
huge_palloc(size_t size, size_t alignment, bool zero)
{
void *ret;
size_t csize;
size_t psize;
extent_node_t *node;
bool zeroed;
/* 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 nullptr;
}
/* Allocate an extent node with which to track the chunk. */
node = base_node_alloc();
if (!node)
return nullptr;
ret = chunk_alloc(csize, alignment, false, &zeroed);
if (!ret) {
base_node_dealloc(node);
return nullptr;
}
if (zero) {
chunk_ensure_zero(ret, csize, zeroed);
}
/* Insert node into huge. */
node->addr = ret;
psize = PAGE_CEILING(size);
node->size = psize;
malloc_mutex_lock(&huge_mtx);
extent_tree_ad_insert(&huge, node);
huge_nmalloc++;
/* Although we allocated space for csize bytes, we indicate that we've
* allocated only psize bytes.
*
* If DECOMMIT is defined, this is a reasonable thing to do, since
* we'll explicitly decommit the bytes in excess of psize.
*
* If DECOMMIT is not defined, then we're relying on the OS to be lazy
* about how it allocates physical pages to mappings. If we never
* touch the pages in excess of psize, the OS won't allocate a physical
* page, and we won't use more than psize bytes of physical memory.
*
* A correct program will only touch memory in excess of how much it
* requested if it first calls malloc_usable_size and finds out how
* much space it has to play with. But because we set node->size =
* psize above, malloc_usable_size will return psize, not csize, and
* the program will (hopefully) never touch bytes in excess of psize.
* Thus those bytes won't take up space in physical memory, and we can
* reasonably claim we never "allocated" them in the first place. */
huge_allocated += psize;
huge_mapped += csize;
malloc_mutex_unlock(&huge_mtx);
#ifdef MALLOC_DECOMMIT
if (csize - psize > 0)
pages_decommit((void *)((uintptr_t)ret + psize), csize - psize);
#endif
if (zero == false) {
if (opt_junk)
# ifdef MALLOC_DECOMMIT
memset(ret, kAllocJunk, psize);
# else
memset(ret, kAllocJunk, csize);
# endif
else if (opt_zero)
# ifdef MALLOC_DECOMMIT
memset(ret, 0, psize);
# else
memset(ret, 0, csize);
# 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)) {
size_t psize = PAGE_CEILING(size);
if (size < oldsize) {
memset((void *)((uintptr_t)ptr + size), kAllocPoison, oldsize
- size);
}
#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 = const_cast<void*>(ptr);
node = extent_tree_ad_search(&huge, &key);
MOZ_ASSERT(node);
MOZ_ASSERT(node->size == oldsize);
huge_allocated -= oldsize - psize;
/* No need to change huge_mapped, because we didn't
* (un)map anything. */
node->size = psize;
malloc_mutex_unlock(&huge_mtx);
} else if (psize > oldsize) {
pages_commit((void *)((uintptr_t)ptr + oldsize),
psize - oldsize);
}
#endif
/* Although we don't have to commit or decommit anything if
* DECOMMIT is not defined and the size class didn't change, we
* do need to update the recorded size if the size increased,
* so malloc_usable_size doesn't return a value smaller than
* what was requested via realloc(). */
if (psize > oldsize) {
/* Update recorded size. */
extent_node_t *node, key;
malloc_mutex_lock(&huge_mtx);
key.addr = const_cast<void*>(ptr);
node = extent_tree_ad_search(&huge, &key);
MOZ_ASSERT(node);
MOZ_ASSERT(node->size == oldsize);
huge_allocated += psize - oldsize;
/* No need to change huge_mapped, because we didn't
* (un)map anything. */
node->size = psize;
malloc_mutex_unlock(&huge_mtx);
}
if (opt_zero && size > oldsize) {
memset((void *)((uintptr_t)ptr + oldsize), 0, size
- oldsize);
}
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)
return nullptr;
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);
MOZ_ASSERT(node);
MOZ_ASSERT(node->addr == ptr);
extent_tree_ad_remove(&huge, node);
huge_ndalloc++;
huge_allocated -= node->size;
huge_mapped -= CHUNK_CEILING(node->size);
malloc_mutex_unlock(&huge_mtx);
/* Unmap chunk. */
chunk_dealloc(node->addr, CHUNK_CEILING(node->size), HUGE_CHUNK);
base_node_dealloc(node);
}
/*
* 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))
#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_DARWIN)
extern "C" void register_zone(void);
#endif
#if !defined(MOZ_MEMORY_WINDOWS)
static
#endif
bool
malloc_init_hard(void)
{
unsigned i;
const char *opts;
long result;
#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();
#elif defined(MOZ_MEMORY_DARWIN)
pthread_key_create(&tlsIndex, nullptr);
#endif
/* Get page size and number of CPUs */
#ifdef MOZ_MEMORY_WINDOWS
{
SYSTEM_INFO info;
GetSystemInfo(&info);
result = info.dwPageSize;
}
#else
result = sysconf(_SC_PAGESIZE);
MOZ_ASSERT(result != -1);
#endif
/* We assume that the page size is a power of 2. */
MOZ_ASSERT(((result - 1) & result) == 0);
#ifdef MALLOC_STATIC_SIZES
if (pagesize % (size_t) result) {
_malloc_message(_getprogname(),
"Compile-time page size does not divide the runtime one.\n");
moz_abort();
}
#else
pagesize = (size_t) result;
pagesize_mask = (size_t) result - 1;
pagesize_2pow = ffs((int)result) - 1;
#endif
/* Get runtime configuration. */
if ((opts = getenv("MALLOC_OPTIONS"))) {
for (i = 0; opts[i] != '\0'; i++) {
unsigned j, nreps;
bool nseen;
/* Parse repetition count, if any. */
for (nreps = 0, nseen = false;; i++, nseen = true) {
switch (opts[i]) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
case '8': case '9':
nreps *= 10;
nreps += opts[i] - '0';
break;
default:
goto MALLOC_OUT;
}
}
MALLOC_OUT:
if (nseen == false)
nreps = 1;
for (j = 0; j < nreps; j++) {
switch (opts[i]) {
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 MOZ_DEBUG
case 'j':
opt_junk = false;
break;
case 'J':
opt_junk = true;
break;
#endif
#ifndef MALLOC_STATIC_SIZES
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;
#endif
#ifndef MALLOC_STATIC_SIZES
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;
#endif
#ifdef MOZ_DEBUG
case 'z':
opt_zero = false;
break;
case 'Z':
opt_zero = true;
break;
#endif
default: {
char cbuf[2];
cbuf[0] = opts[i];
cbuf[1] = '\0';
_malloc_message(_getprogname(),
": (malloc) Unsupported character "
"in malloc options: '", cbuf,
"'\n");
}
}
}
}
}
#ifndef MALLOC_STATIC_SIZES
/* 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);
MOZ_ASSERT(opt_quantum_2pow >= TINY_MIN_2POW);
ntbins = opt_quantum_2pow - TINY_MIN_2POW;
MOZ_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;
MOZ_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);
arena_chunk_header_npages = calculate_arena_header_pages();
arena_maxclass = calculate_arena_maxclass();
recycle_limit = CHUNK_RECYCLE_LIMIT * chunksize;
#endif
recycled_size = 0;
/* Various sanity checks that regard configuration. */
MOZ_ASSERT(quantum >= sizeof(void *));
MOZ_ASSERT(quantum <= pagesize);
MOZ_ASSERT(chunksize >= pagesize);
MOZ_ASSERT(quantum * 4 <= chunksize);
/* Initialize chunks data. */
malloc_mutex_init(&chunks_mtx);
extent_tree_szad_new(&chunks_szad_mmap);
extent_tree_ad_new(&chunks_ad_mmap);
/* Initialize huge allocation data. */
malloc_mutex_init(&huge_mtx);
extent_tree_ad_new(&huge);
huge_nmalloc = 0;
huge_ndalloc = 0;
huge_allocated = 0;
huge_mapped = 0;
/* Initialize base allocation data structures. */
base_mapped = 0;
base_committed = 0;
base_nodes = nullptr;
malloc_mutex_init(&base_mtx);
malloc_spin_init(&arenas_lock);
/*
* Initialize one arena here.
*/
arenas_extend();
if (!arenas || !arenas[0]) {
#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]);
#elif defined(MOZ_MEMORY_DARWIN)
pthread_setspecific(tlsIndex, arenas[0]);
#else
arenas_map = arenas[0];
#endif
#endif
chunk_rtree = malloc_rtree_new((SIZEOF_PTR << 3) - opt_chunk_2pow);
if (!chunk_rtree)
return (true);
malloc_initialized = true;
#if !defined(MOZ_MEMORY_WINDOWS) && !defined(MOZ_MEMORY_DARWIN)
/* Prevent potential deadlock on malloc locks after fork. */
pthread_atfork(_malloc_prefork, _malloc_postfork_parent, _malloc_postfork_child);
#endif
#if defined(MOZ_MEMORY_DARWIN)
register_zone();
#endif
#ifndef MOZ_MEMORY_WINDOWS
malloc_mutex_unlock(&init_lock);
#endif
return (false);
}
/*
* End general internal functions.
*/
/******************************************************************************/
/*
* Begin malloc(3)-compatible functions.
*/
MOZ_MEMORY_API void *
malloc_impl(size_t size)
{
void *ret;
if (malloc_init()) {
ret = nullptr;
goto RETURN;
}
if (size == 0) {
size = 1;
}
ret = imalloc(size);
RETURN:
if (!ret) {
errno = ENOMEM;
}
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.
*/
#ifndef MOZ_REPLACE_MALLOC
#if defined(__GNUC__) && !defined(MOZ_MEMORY_DARWIN)
#define MOZ_MEMORY_ELF
#endif
#endif /* MOZ_REPLACE_MALLOC */
#ifdef MOZ_MEMORY_ELF
#define MEMALIGN memalign_internal
extern "C"
#else
#define MEMALIGN memalign_impl
MOZ_MEMORY_API
#endif
void *
MEMALIGN(size_t alignment, size_t size)
{
void *ret;
MOZ_ASSERT(((alignment - 1) & alignment) == 0);
if (malloc_init()) {
ret = nullptr;
goto RETURN;
}
if (size == 0) {
size = 1;
}
alignment = alignment < sizeof(void*) ? sizeof(void*) : alignment;
ret = ipalloc(alignment, size);
RETURN:
return (ret);
}
#ifdef MOZ_MEMORY_ELF
extern void *
memalign_impl(size_t alignment, size_t size) __attribute__((alias ("memalign_internal"), visibility ("default")));
#endif
MOZ_MEMORY_API int
posix_memalign_impl(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 *)) {
return (EINVAL);
}
/* The 0-->1 size promotion is done in the memalign() call below */
result = MEMALIGN(alignment, size);
if (!result)
return (ENOMEM);
*memptr = result;
return (0);
}
MOZ_MEMORY_API void *
aligned_alloc_impl(size_t alignment, size_t size)
{
if (size % alignment) {
return nullptr;
}
return MEMALIGN(alignment, size);
}
MOZ_MEMORY_API void *
valloc_impl(size_t size)
{
return (MEMALIGN(pagesize, size));
}
MOZ_MEMORY_API void *
calloc_impl(size_t num, size_t size)
{
void *ret;
size_t num_size;
if (malloc_init()) {
num_size = 0;
ret = nullptr;
goto RETURN;
}
num_size = num * size;
if (num_size == 0) {
num_size = 1;
/*
* 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 = nullptr;
goto RETURN;
}
ret = icalloc(num_size);
RETURN:
if (!ret) {
errno = ENOMEM;
}
return (ret);
}
MOZ_MEMORY_API void *
realloc_impl(void *ptr, size_t size)
{
void *ret;
if (size == 0) {
size = 1;
}
if (ptr) {
MOZ_ASSERT(malloc_initialized);
ret = iralloc(ptr, size);
if (!ret) {
errno = ENOMEM;
}
} else {
if (malloc_init())
ret = nullptr;
else
ret = imalloc(size);
if (!ret) {
errno = ENOMEM;
}
}
return (ret);
}
MOZ_MEMORY_API void
free_impl(void *ptr)
{
size_t offset;
/*
* A version of idalloc that checks for nullptr pointer but only for
* huge allocations assuming that CHUNK_ADDR2OFFSET(nullptr) == 0.
*/
MOZ_ASSERT(CHUNK_ADDR2OFFSET(nullptr) == 0);
offset = CHUNK_ADDR2OFFSET(ptr);
if (offset != 0)
arena_dalloc(ptr, offset);
else if (ptr)
huge_dalloc(ptr);
}
/*
* End malloc(3)-compatible functions.
*/
/******************************************************************************/
/*
* Begin non-standard functions.
*/
/* This was added by Mozilla for use by SQLite. */
MOZ_MEMORY_API size_t
malloc_good_size_impl(size_t size)
{
/*
* This duplicates the logic in imalloc(), arena_malloc() and
* arena_malloc_small().
*/
if (size < small_min) {
/* Small (tiny). */
size = pow2_ceil(size);
/*
* We omit the #ifdefs from arena_malloc_small() --
* it can be inaccurate with its size in some cases, but this
* function must be accurate.
*/
if (size < (1U << TINY_MIN_2POW))
size = (1U << TINY_MIN_2POW);
} else if (size <= small_max) {
/* Small (quantum-spaced). */
size = QUANTUM_CEILING(size);
} else if (size <= bin_maxclass) {
/* Small (sub-page). */
size = pow2_ceil(size);
} else if (size <= arena_maxclass) {
/* Large. */
size = PAGE_CEILING(size);
} else {
/*
* Huge. We use PAGE_CEILING to get psize, instead of using
* CHUNK_CEILING to get csize. This ensures that this
* malloc_usable_size(malloc(n)) always matches
* malloc_good_size(n).
*/
size = PAGE_CEILING(size);
}
return size;
}
MOZ_MEMORY_API size_t
malloc_usable_size_impl(MALLOC_USABLE_SIZE_CONST_PTR void *ptr)
{
return (isalloc_validate(ptr));
}
MOZ_JEMALLOC_API void
jemalloc_stats_impl(jemalloc_stats_t *stats)
{
size_t i, non_arena_mapped, chunk_header_size;
MOZ_ASSERT(stats);
/*
* Gather runtime settings.
*/
stats->opt_junk = opt_junk;
stats->opt_zero = opt_zero;
stats->narenas = narenas;
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->allocated = 0;
stats->waste = 0;
stats->page_cache = 0;
stats->bookkeeping = 0;
stats->bin_unused = 0;
non_arena_mapped = 0;
/* Get huge mapped/allocated. */
malloc_mutex_lock(&huge_mtx);
non_arena_mapped += huge_mapped;
stats->allocated += huge_allocated;
MOZ_ASSERT(huge_mapped >= huge_allocated);
malloc_mutex_unlock(&huge_mtx);
/* Get base mapped/allocated. */
malloc_mutex_lock(&base_mtx);
non_arena_mapped += base_mapped;
stats->bookkeeping += base_committed;
MOZ_ASSERT(base_mapped >= base_committed);
malloc_mutex_unlock(&base_mtx);
malloc_spin_lock(&arenas_lock);
/* Iterate over arenas. */
for (i = 0; i < narenas; i++) {
arena_t *arena = arenas[i];
size_t arena_mapped, arena_allocated, arena_committed, arena_dirty, j,
arena_unused, arena_headers;
arena_run_t* run;
arena_chunk_map_t* mapelm;
if (!arena) {
continue;
}
arena_headers = 0;
arena_unused = 0;
malloc_spin_lock(&arena->lock);
arena_mapped = arena->stats.mapped;
/* "committed" counts dirty and allocated memory. */
arena_committed = arena->stats.committed << pagesize_2pow;
arena_allocated = arena->stats.allocated_small +
arena->stats.allocated_large;
arena_dirty = arena->ndirty << pagesize_2pow;
for (j = 0; j < ntbins + nqbins + nsbins; j++) {
arena_bin_t* bin = &arena->bins[j];
size_t bin_unused = 0;
rb_foreach_begin(arena_chunk_map_t, link, &bin->runs, mapelm) {
run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
bin_unused += run->nfree * bin->reg_size;
} rb_foreach_end(arena_chunk_map_t, link, &bin->runs, mapelm)
if (bin->runcur) {
bin_unused += bin->runcur->nfree * bin->reg_size;
}
arena_unused += bin_unused;
arena_headers += bin->stats.curruns * bin->reg0_offset;
}
malloc_spin_unlock(&arena->lock);
MOZ_ASSERT(arena_mapped >= arena_committed);
MOZ_ASSERT(arena_committed >= arena_allocated + arena_dirty);
/* "waste" is committed memory that is neither dirty nor
* allocated. */
stats->mapped += arena_mapped;
stats->allocated += arena_allocated;
stats->page_cache += arena_dirty;
stats->waste += arena_committed -
arena_allocated - arena_dirty - arena_unused - arena_headers;
stats->bin_unused += arena_unused;
stats->bookkeeping += arena_headers;
}
malloc_spin_unlock(&arenas_lock);
/* Account for arena chunk headers in bookkeeping rather than waste. */
chunk_header_size =
((stats->mapped / stats->chunksize) * arena_chunk_header_npages) <<
pagesize_2pow;
stats->mapped += non_arena_mapped;
stats->bookkeeping += chunk_header_size;
stats->waste -= chunk_header_size;
MOZ_ASSERT(stats->mapped >= stats->allocated + stats->waste +
stats->page_cache + stats->bookkeeping);
}
#ifdef MALLOC_DOUBLE_PURGE
/* Explicitly remove all of this chunk's MADV_FREE'd pages from memory. */
static void
hard_purge_chunk(arena_chunk_t *chunk)
{
/* See similar logic in arena_purge(). */
size_t i;
for (i = arena_chunk_header_npages; i < chunk_npages; i++) {
/* Find all adjacent pages with CHUNK_MAP_MADVISED set. */
size_t npages;
for (npages = 0;
chunk->map[i + npages].bits & CHUNK_MAP_MADVISED && i + npages < chunk_npages;
npages++) {
/* Turn off the chunk's MADV_FREED bit and turn on its
* DECOMMITTED bit. */
MOZ_DIAGNOSTIC_ASSERT(!(chunk->map[i + npages].bits & CHUNK_MAP_DECOMMITTED));
chunk->map[i + npages].bits ^= CHUNK_MAP_MADVISED_OR_DECOMMITTED;
}
/* We could use mincore to find out which pages are actually
* present, but it's not clear that's better. */
if (npages > 0) {
pages_decommit(((char*)chunk) + (i << pagesize_2pow), npages << pagesize_2pow);
pages_commit(((char*)chunk) + (i << pagesize_2pow), npages << pagesize_2pow);
}
i += npages;
}
}
/* Explicitly remove all of this arena's MADV_FREE'd pages from memory. */
static void
hard_purge_arena(arena_t *arena)
{
malloc_spin_lock(&arena->lock);
while (!LinkedList_IsEmpty(&arena->chunks_madvised)) {
arena_chunk_t *chunk =
LinkedList_Get(arena->chunks_madvised.next,
arena_chunk_t, chunks_madvised_elem);
hard_purge_chunk(chunk);
LinkedList_Remove(&chunk->chunks_madvised_elem);
}
malloc_spin_unlock(&arena->lock);
}
MOZ_JEMALLOC_API void
jemalloc_purge_freed_pages_impl()
{
size_t i;
malloc_spin_lock(&arenas_lock);
for (i = 0; i < narenas; i++) {
arena_t *arena = arenas[i];
if (arena)
hard_purge_arena(arena);
}
malloc_spin_unlock(&arenas_lock);
}
#else /* !defined MALLOC_DOUBLE_PURGE */
MOZ_JEMALLOC_API void
jemalloc_purge_freed_pages_impl()
{
/* Do nothing. */
}
#endif /* defined MALLOC_DOUBLE_PURGE */
#ifdef MOZ_MEMORY_WINDOWS
void*
_recalloc(void *ptr, size_t count, size_t size)
{
size_t oldsize = ptr ? 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_impl(ptr, newsize);
if (ptr && 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 nullptr;
}
size_t
_msize(void *ptr)
{
return malloc_usable_size_impl(ptr);
}
#endif
MOZ_JEMALLOC_API void
jemalloc_free_dirty_pages_impl(void)
{
size_t i;
malloc_spin_lock(&arenas_lock);
for (i = 0; i < narenas; i++) {
arena_t *arena = arenas[i];
if (arena) {
malloc_spin_lock(&arena->lock);
arena_purge(arena, true);
malloc_spin_unlock(&arena->lock);
}
}
malloc_spin_unlock(&arenas_lock);
}
/*
* 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.
*/
#ifndef MOZ_MEMORY_DARWIN
static
#endif
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])
malloc_spin_lock(&arenas[i]->lock);
}
malloc_mutex_lock(&base_mtx);
malloc_mutex_lock(&huge_mtx);
}
#ifndef MOZ_MEMORY_DARWIN
static
#endif
void
_malloc_postfork_parent(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])
malloc_spin_unlock(&arenas[i]->lock);
}
malloc_spin_unlock(&arenas_lock);
}
#ifndef MOZ_MEMORY_DARWIN
static
#endif
void
_malloc_postfork_child(void)
{
unsigned i;
/* Reinitialize all mutexes, now that fork() has completed. */
malloc_mutex_init(&huge_mtx);
malloc_mutex_init(&base_mtx);
for (i = 0; i < narenas; i++) {
if (arenas[i])
malloc_spin_init(&arenas[i]->lock);
}
malloc_spin_init(&arenas_lock);
}
/*
* End library-private functions.
*/
/******************************************************************************/
#ifdef HAVE_DLOPEN
# include <dlfcn.h>
#endif
#if defined(MOZ_MEMORY_DARWIN)
__attribute__((constructor))
void
jemalloc_darwin_init(void)
{
if (malloc_init_hard())
moz_abort();
}
#endif
/*
* is_malloc(malloc_impl) is some macro magic to detect if malloc_impl is
* defined as "malloc" in mozmemory_wrap.h
*/
#define malloc_is_malloc 1
#define is_malloc_(a) malloc_is_ ## a
#define is_malloc(a) is_malloc_(a)
#if !defined(MOZ_MEMORY_DARWIN) && (is_malloc(malloc_impl) == 1)
# if 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.
*/
extern "C" {
MOZ_EXPORT void (*__free_hook)(void *ptr) = free_impl;
MOZ_EXPORT void *(*__malloc_hook)(size_t size) = malloc_impl;
MOZ_EXPORT void *(*__realloc_hook)(void *ptr, size_t size) = realloc_impl;
MOZ_EXPORT void *(*__memalign_hook)(size_t alignment, size_t size) = MEMALIGN;
}
# 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
#endif
#ifdef MOZ_MEMORY_WINDOWS
/*
* In the new style jemalloc integration jemalloc is built as a separate
* shared library. Since we're no longer hooking into the CRT binary,
* we need to initialize the heap at the first opportunity we get.
* DLL_PROCESS_ATTACH in DllMain is that opportunity.
*/
BOOL APIENTRY DllMain(HINSTANCE hModule,
DWORD reason,
LPVOID lpReserved)
{
switch (reason) {
case DLL_PROCESS_ATTACH:
/* Don't force the system to page DllMain back in every time
* we create/destroy a thread */
DisableThreadLibraryCalls(hModule);
/* Initialize the heap */
malloc_init_hard();
break;
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
#endif