nagai/fune
3
0
Fork 0
forked from mirrors/gecko-dev
Code Pull requests Activity
fune/memory/build/mozjemalloc.cpp
Mike Hommey 5f11951b9b Bug 1441335 - Fix base allocator commit evaluation. r=njn 
Base allocator commit stats were added in bug 515556, along other commit
stats, but they have actually been wrong since then: the committed count
is updated with the difference between pbase_next_addr and
base_next_decommitted *after* the latter is set to the former, making
the difference always 0.

--HG--
extra : rebase_source : a2aed523314549a37a61bd4ab300c98f198f9252
2018-02-27 07:39:34 +09:00

4937 lines
142 KiB
C++
Raw Blame History

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// Portions of this file were originally under the following license:
//
// Copyright (C) 2006-2008 Jason Evans <jasone@FreeBSD.org>.
// All rights reserved.
// Copyright (C) 2007-2017 Mozilla Foundation.
//
// 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 | 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 "mozjemalloc.h"
#include "mozjemalloc_types.h"
#include <cstring>
#include <cerrno>
#ifdef XP_WIN
#include <io.h>
#include <windows.h>
#else
#include <sys/mman.h>
#include <unistd.h>
#endif
#ifdef XP_DARWIN
#include <libkern/OSAtomic.h>
#include <mach/mach_init.h>
#include <mach/vm_map.h>
#endif
#include "mozilla/Atomics.h"
#include "mozilla/Alignment.h"
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/DoublyLinkedList.h"
#include "mozilla/Likely.h"
#include "mozilla/MathAlgorithms.h"
#include "mozilla/Sprintf.h"
// Note: MozTaggedAnonymousMmap() could call an LD_PRELOADed mmap
// instead of the one defined here; use only MozTagAnonymousMemory().
#include "mozilla/TaggedAnonymousMemory.h"
#include "mozilla/ThreadLocal.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/Unused.h"
#include "mozilla/fallible.h"
#include "rb.h"
#include "Mutex.h"
#include "Utils.h"
using namespace mozilla;
// 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 XP_DARWIN
#define MALLOC_DOUBLE_PURGE
#endif
#ifdef XP_WIN
#define MALLOC_DECOMMIT
#endif
// When MALLOC_STATIC_PAGESIZE is defined, the page size is fixed at
// compile-time for better performance, as opposed to determined at
// runtime. Some platforms can have different page sizes at runtime
// depending on kernel configuration, so they are opted out by default.
// Debug builds are opted out too, for test coverage.
#ifndef MOZ_DEBUG
#if !defined(__ia64__) && !defined(__sparc__) && !defined(__mips__) && \
!defined(__aarch64__)
#define MALLOC_STATIC_PAGESIZE 1
#endif
#endif
#ifdef XP_WIN
#define STDERR_FILENO 2
// Implement getenv without using malloc.
static char mozillaMallocOptionsBuf[64];
#define getenv xgetenv
static char*
getenv(const char* name)
{
if (GetEnvironmentVariableA(
name, mozillaMallocOptionsBuf, sizeof(mozillaMallocOptionsBuf)) > 0) {
return mozillaMallocOptionsBuf;
}
return nullptr;
}
#endif
#ifndef XP_WIN
#ifndef MADV_FREE
#define MADV_FREE MADV_DONTNEED
#endif
#endif
// 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(XP_LINUX) && !defined(__alpha__)) || \
(defined(__FreeBSD_kernel__) && 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(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
// ***************************************************************************
// Structures for chunk headers for chunks used for non-huge allocations.
struct arena_t;
// Each element of the chunk map corresponds to one page within the chunk.
struct arena_chunk_map_t
{
// Linkage for run trees. There are two disjoint uses:
//
// 1) arena_t's tree or available runs.
// 2) arena_run_t conceptually uses this linkage for in-use non-full
// runs, rather than directly embedding linkage.
RedBlackTreeNode<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)
};
// Arena chunk header.
struct arena_chunk_t
{
// Arena that owns the chunk.
arena_t* arena;
// Linkage for the arena's tree of dirty chunks.
RedBlackTreeNode<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.
DoublyLinkedListElement<arena_chunk_t> 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.
};
// ***************************************************************************
// Constants defining allocator size classes and behavior.
// 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.
static const size_t kCacheLineSize = 64;
// 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 XP_WIN
static const size_t kMinTinyClass = sizeof(void*) * 2;
#else
static const size_t kMinTinyClass = sizeof(void*);
#endif
// Maximum tiny size class.
static const size_t kMaxTinyClass = 8;
// Amount (quantum) separating quantum-spaced size classes.
static const size_t kQuantum = 16;
static const size_t kQuantumMask = kQuantum - 1;
// Smallest quantum-spaced size classes. It could actually also be labelled a
// tiny allocation, and is spaced as such from the largest tiny size class.
// Tiny classes being powers of 2, this is twice as large as the largest of
// them.
static const size_t kMinQuantumClass = kMaxTinyClass * 2;
// Largest quantum-spaced size classes.
static const size_t kMaxQuantumClass = 512;
static_assert(kMaxQuantumClass % kQuantum == 0,
"kMaxQuantumClass is not a multiple of kQuantum");
// Number of (2^n)-spaced tiny classes.
static const size_t kNumTinyClasses =
LOG2(kMinQuantumClass) - LOG2(kMinTinyClass);
// Number of quantum-spaced classes.
static const size_t kNumQuantumClasses = kMaxQuantumClass / kQuantum;
// Size and alignment of memory chunks that are allocated by the OS's virtual
// memory system.
static const size_t kChunkSize = 1_MiB;
static const size_t kChunkSizeMask = kChunkSize - 1;
#ifdef MALLOC_STATIC_PAGESIZE
// 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))
static const size_t gPageSize = 8_KiB;
#elif defined(__powerpc64__)
static const size_t gPageSize = 64_KiB;
#else
static const size_t gPageSize = 4_KiB;
#endif
#else
static size_t gPageSize;
#endif
#ifdef MALLOC_STATIC_PAGESIZE
#define DECLARE_GLOBAL(type, name)
#define DEFINE_GLOBALS
#define END_GLOBALS
#define DEFINE_GLOBAL(type) static const type
#define GLOBAL_LOG2 LOG2
#define GLOBAL_ASSERT_HELPER1(x) static_assert(x, #x)
#define GLOBAL_ASSERT_HELPER2(x, y) static_assert(x, y)
#define GLOBAL_ASSERT(...) \
MACRO_CALL( \
MOZ_PASTE_PREFIX_AND_ARG_COUNT(GLOBAL_ASSERT_HELPER, __VA_ARGS__), \
(__VA_ARGS__))
#else
#define DECLARE_GLOBAL(type, name) static type name;
#define DEFINE_GLOBALS \
static void DefineGlobals() \
{
#define END_GLOBALS }
#define DEFINE_GLOBAL(type)
#define GLOBAL_LOG2 FloorLog2
#define GLOBAL_ASSERT MOZ_RELEASE_ASSERT
#endif
DECLARE_GLOBAL(size_t, gMaxSubPageClass)
DECLARE_GLOBAL(uint8_t, gNumSubPageClasses)
DECLARE_GLOBAL(uint8_t, gPageSize2Pow)
DECLARE_GLOBAL(size_t, gPageSizeMask)
DECLARE_GLOBAL(size_t, gChunkNumPages)
DECLARE_GLOBAL(size_t, gChunkHeaderNumPages)
DECLARE_GLOBAL(size_t, gMaxLargeClass)
DEFINE_GLOBALS
// Largest sub-page size class.
DEFINE_GLOBAL(size_t) gMaxSubPageClass = gPageSize / 2;
// Max size class for bins.
#define gMaxBinClass gMaxSubPageClass
// Number of (2^n)-spaced sub-page bins.
DEFINE_GLOBAL(uint8_t)
gNumSubPageClasses = GLOBAL_LOG2(gMaxSubPageClass) - LOG2(kMaxQuantumClass);
DEFINE_GLOBAL(uint8_t) gPageSize2Pow = GLOBAL_LOG2(gPageSize);
DEFINE_GLOBAL(size_t) gPageSizeMask = gPageSize - 1;
// Number of pages in a chunk.
DEFINE_GLOBAL(size_t) gChunkNumPages = kChunkSize >> gPageSize2Pow;
// Number of pages necessary for a chunk header.
DEFINE_GLOBAL(size_t)
gChunkHeaderNumPages =
((sizeof(arena_chunk_t) + sizeof(arena_chunk_map_t) * (gChunkNumPages - 1) +
gPageSizeMask) &
~gPageSizeMask) >>
gPageSize2Pow;
// Max size class for arenas.
DEFINE_GLOBAL(size_t)
gMaxLargeClass = kChunkSize - (gChunkHeaderNumPages << gPageSize2Pow);
// Various sanity checks that regard configuration.
GLOBAL_ASSERT(1ULL << gPageSize2Pow == gPageSize,
"Page size is not a power of two");
GLOBAL_ASSERT(kQuantum >= sizeof(void*));
GLOBAL_ASSERT(kQuantum <= gPageSize);
GLOBAL_ASSERT(kChunkSize >= gPageSize);
GLOBAL_ASSERT(kQuantum * 4 <= kChunkSize);
END_GLOBALS
// Recycle at most 128 MiB of chunks. This means we retain at most
// 6.25% of the process address space on a 32-bit OS for later use.
static const size_t gRecycleLimit = 128_MiB;
// The current amount of recycled bytes, updated atomically.
static Atomic<size_t, ReleaseAcquire> gRecycledSize;
// Maximum number of dirty pages per arena.
#define DIRTY_MAX_DEFAULT (1U << 8)
static size_t opt_dirty_max = DIRTY_MAX_DEFAULT;
// Return the smallest chunk multiple that is >= s.
#define CHUNK_CEILING(s) (((s) + kChunkSizeMask) & ~kChunkSizeMask)
// Return the smallest cacheline multiple that is >= s.
#define CACHELINE_CEILING(s) \
(((s) + (kCacheLineSize - 1)) & ~(kCacheLineSize - 1))
// Return the smallest quantum multiple that is >= a.
#define QUANTUM_CEILING(a) (((a) + (kQuantumMask)) & ~(kQuantumMask))
// Return the smallest pagesize multiple that is >= s.
#define PAGE_CEILING(s) (((s) + gPageSizeMask) & ~gPageSizeMask)
// ***************************************************************************
// 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
static void*
base_alloc(size_t aSize);
// Set to true once the allocator has been initialized.
static Atomic<bool> malloc_initialized(false);
static StaticMutex gInitLock;
// ***************************************************************************
// Statistics data structures.
struct arena_stats_t
{
// 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_t::AllocRun.
HUGE_CHUNK, // used to back huge allocations (e.g. arena_t::MallocHuge).
RECYCLED_CHUNK, // chunk has been stored for future use by chunk_recycle.
};
// Tree of extents.
struct extent_node_t
{
// Linkage for the size/address-ordered tree.
RedBlackTreeNode<extent_node_t> mLinkBySize;
// Linkage for the address-ordered tree.
RedBlackTreeNode<extent_node_t> mLinkByAddr;
// Pointer to the extent that this tree node is responsible for.
void* mAddr;
// Total region size.
size_t mSize;
union {
// What type of chunk is there; used for chunk recycling.
ChunkType mChunkType;
// A pointer to the associated arena, for huge allocations.
arena_t* mArena;
};
};
struct ExtentTreeSzTrait
{
static RedBlackTreeNode<extent_node_t>& GetTreeNode(extent_node_t* aThis)
{
return aThis->mLinkBySize;
}
static inline Order Compare(extent_node_t* aNode, extent_node_t* aOther)
{
Order ret = CompareInt(aNode->mSize, aOther->mSize);
return (ret != Order::eEqual) ? ret
: CompareAddr(aNode->mAddr, aOther->mAddr);
}
};
struct ExtentTreeTrait
{
static RedBlackTreeNode<extent_node_t>& GetTreeNode(extent_node_t* aThis)
{
return aThis->mLinkByAddr;
}
static inline Order Compare(extent_node_t* aNode, extent_node_t* aOther)
{
return CompareAddr(aNode->mAddr, aOther->mAddr);
}
};
struct ExtentTreeBoundsTrait : public ExtentTreeTrait
{
static inline Order Compare(extent_node_t* aKey, extent_node_t* aNode)
{
uintptr_t key_addr = reinterpret_cast<uintptr_t>(aKey->mAddr);
uintptr_t node_addr = reinterpret_cast<uintptr_t>(aNode->mAddr);
size_t node_size = aNode->mSize;
// Is aKey within aNode?
if (node_addr <= key_addr && key_addr < node_addr + node_size) {
return Order::eEqual;
}
return CompareAddr(aKey->mAddr, aNode->mAddr);
}
};
// Describe size classes to which allocations are rounded up to.
// TODO: add large and huge types when the arena allocation code
// changes in a way that allows it to be beneficial.
class SizeClass
{
public:
enum ClassType
{
Tiny,
Quantum,
SubPage,
Large,
};
explicit inline SizeClass(size_t aSize)
{
if (aSize <= kMaxTinyClass) {
mType = Tiny;
mSize = std::max(RoundUpPow2(aSize), kMinTinyClass);
} else if (aSize <= kMaxQuantumClass) {
mType = Quantum;
mSize = QUANTUM_CEILING(aSize);
} else if (aSize <= gMaxSubPageClass) {
mType = SubPage;
mSize = RoundUpPow2(aSize);
} else if (aSize <= gMaxLargeClass) {
mType = Large;
mSize = PAGE_CEILING(aSize);
} else {
MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Invalid size");
}
}
SizeClass& operator=(const SizeClass& aOther) = default;
bool operator==(const SizeClass& aOther) { return aOther.mSize == mSize; }
size_t Size() { return mSize; }
ClassType Type() { return mType; }
SizeClass Next() { return SizeClass(mSize + 1); }
private:
ClassType mType;
size_t mSize;
};
// ***************************************************************************
// Radix tree data structures.
//
// The number of bits passed to the template is the number of significant bits
// in an address to do a radix lookup with.
//
// An address is looked up by splitting it in kBitsPerLevel bit chunks, except
// the most significant bits, where the bit chunk is kBitsAtLevel1 which can be
// different if Bits is not a multiple of kBitsPerLevel.
//
// With e.g. sizeof(void*)=4, Bits=16 and kBitsPerLevel=8, an address is split
// like the following:
// 0x12345678 -> mRoot[0x12][0x34]
template<size_t Bits>
class AddressRadixTree
{
// Size of each radix tree node (as a power of 2).
// This impacts tree depth.
#ifdef HAVE_64BIT_BUILD
static const size_t kNodeSize = kCacheLineSize;
#else
static const size_t kNodeSize = 16_KiB;
#endif
static const size_t kBitsPerLevel = LOG2(kNodeSize) - LOG2(sizeof(void*));
static const size_t kBitsAtLevel1 =
(Bits % kBitsPerLevel) ? Bits % kBitsPerLevel : kBitsPerLevel;
static const size_t kHeight = (Bits + kBitsPerLevel - 1) / kBitsPerLevel;
static_assert(kBitsAtLevel1 + (kHeight - 1) * kBitsPerLevel == Bits,
"AddressRadixTree parameters don't work out");
Mutex mLock;
void** mRoot;
public:
bool Init();
inline void* Get(void* aAddr);
// Returns whether the value was properly set.
inline bool Set(void* aAddr, void* aValue);
inline bool Unset(void* aAddr) { return Set(aAddr, nullptr); }
private:
inline void** GetSlot(void* aAddr, bool aCreate = false);
};
// ***************************************************************************
// Arena data structures.
struct arena_bin_t;
struct ArenaChunkMapLink
{
static RedBlackTreeNode<arena_chunk_map_t>& GetTreeNode(
arena_chunk_map_t* aThis)
{
return aThis->link;
}
};
struct ArenaRunTreeTrait : public ArenaChunkMapLink
{
static inline Order Compare(arena_chunk_map_t* aNode,
arena_chunk_map_t* aOther)
{
MOZ_ASSERT(aNode);
MOZ_ASSERT(aOther);
return CompareAddr(aNode, aOther);
}
};
struct ArenaAvailTreeTrait : public ArenaChunkMapLink
{
static inline Order Compare(arena_chunk_map_t* aNode,
arena_chunk_map_t* aOther)
{
size_t size1 = aNode->bits & ~gPageSizeMask;
size_t size2 = aOther->bits & ~gPageSizeMask;
Order ret = CompareInt(size1, size2);
return (ret != Order::eEqual)
? ret
: CompareAddr((aNode->bits & CHUNK_MAP_KEY) ? nullptr : aNode,
aOther);
}
};
struct ArenaDirtyChunkTrait
{
static RedBlackTreeNode<arena_chunk_t>& GetTreeNode(arena_chunk_t* aThis)
{
return aThis->link_dirty;
}
static inline Order Compare(arena_chunk_t* aNode, arena_chunk_t* aOther)
{
MOZ_ASSERT(aNode);
MOZ_ASSERT(aOther);
return CompareAddr(aNode, aOther);
}
};
#ifdef MALLOC_DOUBLE_PURGE
namespace mozilla {
template<>
struct GetDoublyLinkedListElement<arena_chunk_t>
{
static DoublyLinkedListElement<arena_chunk_t>& Get(arena_chunk_t* aThis)
{
return aThis->chunks_madvised_elem;
}
};
}
#endif
struct arena_run_t
{
#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
uint32_t mMagic;
#define ARENA_RUN_MAGIC 0x384adf93
// On 64-bit platforms, having the arena_bin_t pointer following
// the mMagic field means there's padding between both fields, making
// the run header larger than necessary.
// But when MOZ_DIAGNOSTIC_ASSERT_ENABLED is not set, starting the
// header with this field followed by the arena_bin_t pointer yields
// the same padding. We do want the mMagic field to appear first, so
// depending whether MOZ_DIAGNOSTIC_ASSERT_ENABLED is set or not, we
// move some field to avoid padding.
// Number of free regions in run.
unsigned mNumFree;
#endif
// Bin this run is associated with.
arena_bin_t* mBin;
// Index of first element that might have a free region.
unsigned mRegionsMinElement;
#if !defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
// Number of free regions in run.
unsigned mNumFree;
#endif
// Bitmask of in-use regions (0: in use, 1: free).
unsigned mRegionsMask[1]; // Dynamically sized.
};
struct arena_bin_t
{
// Current run being used to service allocations of this bin's size
// class.
arena_run_t* mCurrentRun;
// Tree of non-full runs. This tree is used when looking for an
// existing run when mCurrentRun 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.
RedBlackTree<arena_chunk_map_t, ArenaRunTreeTrait> mNonFullRuns;
// Bin's size class.
size_t mSizeClass;
// Total size of a run for this bin's size class.
size_t mRunSize;
// Total number of regions in a run for this bin's size class.
uint32_t mRunNumRegions;
// Number of elements in a run's mRegionsMask for this bin's size class.
uint32_t mRunNumRegionsMask;
// Offset of first region in a run for this bin's size class.
uint32_t mRunFirstRegionOffset;
// Current number of runs in this bin, full or otherwise.
unsigned long mNumRuns;
// Amount of overhead runs are allowed to have.
static constexpr double kRunOverhead = 1.6_percent;
static constexpr double kRunRelaxedOverhead = 2.4_percent;
// Initialize a bin for the given size class.
// The generated run sizes, for a page size of 4 KiB, are:
// size|run size|run size|run size|run
// class|size class|size class|size class|size
// 4 4 KiB 8 4 KiB 16 4 KiB 32 4 KiB
// 48 4 KiB 64 4 KiB 80 4 KiB 96 4 KiB
// 112 4 KiB 128 8 KiB 144 4 KiB 160 8 KiB
// 176 4 KiB 192 4 KiB 208 8 KiB 224 4 KiB
// 240 4 KiB 256 16 KiB 272 4 KiB 288 4 KiB
// 304 12 KiB 320 12 KiB 336 4 KiB 352 8 KiB
// 368 4 KiB 384 8 KiB 400 20 KiB 416 16 KiB
// 432 12 KiB 448 4 KiB 464 16 KiB 480 8 KiB
// 496 20 KiB 512 32 KiB 1024 64 KiB 2048 128 KiB
inline void Init(SizeClass aSizeClass);
};
struct arena_t
{
#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
uint32_t mMagic;
#define ARENA_MAGIC 0x947d3d24
#endif
arena_id_t mId;
// Linkage for the tree of arenas by id.
RedBlackTreeNode<arena_t> mLink;
// All operations on this arena require that lock be locked.
Mutex mLock;
arena_stats_t mStats;
private:
// Tree of dirty-page-containing chunks this arena manages.
RedBlackTree<arena_chunk_t, ArenaDirtyChunkTrait> mChunksDirty;
#ifdef MALLOC_DOUBLE_PURGE
// Head of a linked list of MADV_FREE'd-page-containing chunks this
// arena manages.
DoublyLinkedList<arena_chunk_t> mChunksMAdvised;
#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* mSpare;
public:
// 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 mNumDirty;
// Maximum value allowed for mNumDirty.
size_t mMaxDirty;
private:
// Size/address-ordered tree of this arena's available runs. This tree
// is used for first-best-fit run allocation.
RedBlackTree<arena_chunk_map_t, ArenaAvailTreeTrait> mRunsAvail;
public:
// mBins is used to store rings of free regions of the following sizes,
// assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS.
//
// mBins[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 mBins[1]; // Dynamically sized.
explicit arena_t(arena_params_t* aParams);
private:
void InitChunk(arena_chunk_t* aChunk, bool aZeroed);
void DeallocChunk(arena_chunk_t* aChunk);
arena_run_t* AllocRun(size_t aSize, bool aLarge, bool aZero);
void DallocRun(arena_run_t* aRun, bool aDirty);
MOZ_MUST_USE bool SplitRun(arena_run_t* aRun,
size_t aSize,
bool aLarge,
bool aZero);
void TrimRunHead(arena_chunk_t* aChunk,
arena_run_t* aRun,
size_t aOldSize,
size_t aNewSize);
void TrimRunTail(arena_chunk_t* aChunk,
arena_run_t* aRun,
size_t aOldSize,
size_t aNewSize,
bool dirty);
arena_run_t* GetNonFullBinRun(arena_bin_t* aBin);
inline void* MallocSmall(size_t aSize, bool aZero);
void* MallocLarge(size_t aSize, bool aZero);
void* MallocHuge(size_t aSize, bool aZero);
void* PallocLarge(size_t aAlignment, size_t aSize, size_t aAllocSize);
void* PallocHuge(size_t aSize, size_t aAlignment, bool aZero);
void RallocShrinkLarge(arena_chunk_t* aChunk,
void* aPtr,
size_t aSize,
size_t aOldSize);
bool RallocGrowLarge(arena_chunk_t* aChunk,
void* aPtr,
size_t aSize,
size_t aOldSize);
void* RallocSmallOrLarge(void* aPtr, size_t aSize, size_t aOldSize);
void* RallocHuge(void* aPtr, size_t aSize, size_t aOldSize);
public:
inline void* Malloc(size_t aSize, bool aZero);
void* Palloc(size_t aAlignment, size_t aSize);
inline void DallocSmall(arena_chunk_t* aChunk,
void* aPtr,
arena_chunk_map_t* aMapElm);
void DallocLarge(arena_chunk_t* aChunk, void* aPtr);
void* Ralloc(void* aPtr, size_t aSize, size_t aOldSize);
void Purge(bool aAll);
void HardPurge();
void* operator new(size_t aCount) = delete;
void* operator new(size_t aCount, const fallible_t&)
#if !defined(_MSC_VER) || defined(_CPPUNWIND)
noexcept
#endif
{
MOZ_ASSERT(aCount == sizeof(arena_t));
// Allocate enough space for trailing bins.
return base_alloc(
aCount + (sizeof(arena_bin_t) * (kNumTinyClasses + kNumQuantumClasses +
gNumSubPageClasses - 1)));
}
void operator delete(void*) = delete;
};
struct ArenaTreeTrait
{
static RedBlackTreeNode<arena_t>& GetTreeNode(arena_t* aThis)
{
return aThis->mLink;
}
static inline Order Compare(arena_t* aNode, arena_t* aOther)
{
MOZ_ASSERT(aNode);
MOZ_ASSERT(aOther);
return CompareInt(aNode->mId, aOther->mId);
}
};
// Bookkeeping for all the arenas used by the allocator.
// Arenas are separated in two categories:
// - "private" arenas, used through the moz_arena_* API
// - all the other arenas: the default arena, and thread-local arenas,
// used by the standard API.
class ArenaCollection
{
public:
bool Init()
{
mArenas.Init();
mPrivateArenas.Init();
arena_params_t params;
// The main arena allows more dirty pages than the default for other arenas.
params.mMaxDirty = opt_dirty_max;
mDefaultArena =
mLock.Init() ? CreateArena(/* IsPrivate = */ false, &params) : nullptr;
return bool(mDefaultArena);
}
inline arena_t* GetById(arena_id_t aArenaId, bool aIsPrivate);
arena_t* CreateArena(bool aIsPrivate, arena_params_t* aParams);
void DisposeArena(arena_t* aArena)
{
MutexAutoLock lock(mLock);
(mPrivateArenas.Search(aArena) ? mPrivateArenas : mArenas).Remove(aArena);
// The arena is leaked, and remaining allocations in it still are alive
// until they are freed. After that, the arena will be empty but still
// taking have at least a chunk taking address space. TODO: bug 1364359.
}
using Tree = RedBlackTree<arena_t, ArenaTreeTrait>;
struct Iterator : Tree::Iterator
{
explicit Iterator(Tree* aTree, Tree* aSecondTree)
: Tree::Iterator(aTree)
, mNextTree(aSecondTree)
{
}
Item<Iterator> begin()
{
return Item<Iterator>(this, *Tree::Iterator::begin());
}
Item<Iterator> end() { return Item<Iterator>(this, nullptr); }
arena_t* Next()
{
arena_t* result = Tree::Iterator::Next();
if (!result && mNextTree) {
new (this) Iterator(mNextTree, nullptr);
result = *Tree::Iterator::begin();
}
return result;
}
private:
Tree* mNextTree;
};
Iterator iter() { return Iterator(&mArenas, &mPrivateArenas); }
inline arena_t* GetDefault() { return mDefaultArena; }
Mutex mLock;
private:
arena_t* mDefaultArena;
arena_id_t mLastArenaId;
Tree mArenas;
Tree mPrivateArenas;
};
static ArenaCollection gArenas;
// ******
// Chunks.
static AddressRadixTree<(sizeof(void*) << 3) - LOG2(kChunkSize)> gChunkRTree;
// Protects chunk-related data structures.
static Mutex 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 RedBlackTree<extent_node_t, ExtentTreeSzTrait> gChunksBySize;
static RedBlackTree<extent_node_t, ExtentTreeTrait> gChunksByAddress;
// Protects huge allocation-related data structures.
static Mutex huge_mtx;
// Tree of chunks that are stand-alone huge allocations.
static RedBlackTree<extent_node_t, ExtentTreeTrait> huge;
// Huge allocation statistics.
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 Mutex base_mtx;
static size_t base_mapped;
static size_t base_committed;
// ******
// Arenas.
// The arena associated with the current thread (per
// jemalloc_thread_local_arena) On OSX, __thread/thread_local circles back
// calling malloc to allocate storage on first access on each thread, which
// leads to an infinite loop, but pthread-based TLS somehow doesn't have this
// problem.
#if !defined(XP_DARWIN)
static MOZ_THREAD_LOCAL(arena_t*) thread_arena;
#else
static detail::ThreadLocal<arena_t*, detail::ThreadLocalKeyStorage>
thread_arena;
#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
// ***************************************************************************
// Begin forward declarations.
static void*
chunk_alloc(size_t aSize,
size_t aAlignment,
bool aBase,
bool* aZeroed = nullptr);
static void
chunk_dealloc(void* aChunk, size_t aSize, ChunkType aType);
static void
chunk_ensure_zero(void* aPtr, size_t aSize, bool aZeroed);
static void
huge_dalloc(void* aPtr, arena_t* aArena);
static bool
malloc_init_hard();
#ifdef XP_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.
// ***************************************************************************
// FreeBSD's pthreads implementation calls malloc(3), so the malloc
// implementation has to take pains to avoid infinite recursion during
// initialization.
// Returns whether the allocator was successfully initialized.
static inline bool
malloc_init()
{
if (malloc_initialized == false) {
return malloc_init_hard();
}
return true;
}
static void
_malloc_message(const char* p)
{
#if !defined(XP_WIN)
#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...);
}
#ifdef 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 Utility functions/macros.
// Return the chunk address for allocation address a.
static inline arena_chunk_t*
GetChunkForPtr(const void* aPtr)
{
return (arena_chunk_t*)(uintptr_t(aPtr) & ~kChunkSizeMask);
}
// Return the chunk offset of address a.
static inline size_t
GetChunkOffsetForPtr(const void* aPtr)
{
return (size_t)(uintptr_t(aPtr) & kChunkSizeMask);
}
static inline const char*
_getprogname(void)
{
return "<jemalloc>";
}
// Fill the given range of memory with zeroes or junk depending on opt_junk and
// opt_zero. Callers can force filling with zeroes through the aForceZero
// argument.
static inline void
ApplyZeroOrJunk(void* aPtr, size_t aSize)
{
if (opt_junk) {
memset(aPtr, kAllocJunk, aSize);
} else if (opt_zero) {
memset(aPtr, 0, aSize);
}
}
// ***************************************************************************
static inline void
pages_decommit(void* aAddr, size_t aSize)
{
#ifdef XP_WIN
// 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(aSize, kChunkSize - GetChunkOffsetForPtr(aAddr));
while (aSize > 0) {
if (!VirtualFree(aAddr, pages_size, MEM_DECOMMIT)) {
MOZ_CRASH();
}
aAddr = (void*)((uintptr_t)aAddr + pages_size);
aSize -= pages_size;
pages_size = std::min(aSize, kChunkSize);
}
#else
if (mmap(
aAddr, aSize, PROT_NONE, MAP_FIXED | MAP_PRIVATE | MAP_ANON, -1, 0) ==
MAP_FAILED) {
MOZ_CRASH();
}
MozTagAnonymousMemory(aAddr, aSize, "jemalloc-decommitted");
#endif
}
// Commit pages. Returns whether pages were committed.
MOZ_MUST_USE static inline bool
pages_commit(void* aAddr, size_t aSize)
{
#ifdef XP_WIN
// 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(aSize, kChunkSize - GetChunkOffsetForPtr(aAddr));
while (aSize > 0) {
if (!VirtualAlloc(aAddr, pages_size, MEM_COMMIT, PAGE_READWRITE)) {
return false;
}
aAddr = (void*)((uintptr_t)aAddr + pages_size);
aSize -= pages_size;
pages_size = std::min(aSize, kChunkSize);
}
#else
if (mmap(aAddr,
aSize,
PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | MAP_ANON,
-1,
0) == MAP_FAILED) {
return false;
}
MozTagAnonymousMemory(aAddr, aSize, "jemalloc");
#endif
return true;
}
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, kChunkSize, 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 aSize)
{
void* ret;
size_t csize;
// Round size up to nearest multiple of the cacheline size.
csize = CACHELINE_CEILING(aSize);
MutexAutoLock 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)) {
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
if (!pages_commit(base_next_decommitted,
(uintptr_t)pbase_next_addr -
(uintptr_t)base_next_decommitted)) {
return nullptr;
}
#endif
base_committed +=
(uintptr_t)pbase_next_addr - (uintptr_t)base_next_decommitted;
base_next_decommitted = pbase_next_addr;
}
return ret;
}
static void*
base_calloc(size_t aNumber, size_t aSize)
{
void* ret = base_alloc(aNumber * aSize);
if (ret) {
memset(ret, 0, aNumber * aSize);
}
return ret;
}
static extent_node_t*
base_node_alloc(void)
{
extent_node_t* ret;
base_mtx.Lock();
if (base_nodes) {
ret = base_nodes;
base_nodes = *(extent_node_t**)ret;
base_mtx.Unlock();
} else {
base_mtx.Unlock();
ret = (extent_node_t*)base_alloc(sizeof(extent_node_t));
}
return ret;
}
static void
base_node_dealloc(extent_node_t* aNode)
{
MutexAutoLock lock(base_mtx);
*(extent_node_t**)aNode = base_nodes;
base_nodes = aNode;
}
struct BaseNodeFreePolicy
{
void operator()(extent_node_t* aPtr) { base_node_dealloc(aPtr); }
};
using UniqueBaseNode = UniquePtr<extent_node_t, BaseNodeFreePolicy>;
// End Utility functions/macros.
// ***************************************************************************
// Begin chunk management functions.
#ifdef XP_WIN
static void*
pages_map(void* aAddr, size_t aSize)
{
void* ret = nullptr;
ret = VirtualAlloc(aAddr, aSize, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
return ret;
}
static void
pages_unmap(void* aAddr, size_t aSize)
{
if (VirtualFree(aAddr, 0, MEM_RELEASE) == 0) {
_malloc_message(_getprogname(), ": (malloc) Error in VirtualFree()\n");
}
}
#else
static void
pages_unmap(void* aAddr, size_t aSize)
{
if (munmap(aAddr, aSize) == -1) {
char buf[64];
if (strerror_r(errno, buf, sizeof(buf)) == 0) {
_malloc_message(
_getprogname(), ": (malloc) Error in munmap(): ", buf, "\n");
}
}
}
static void*
pages_map(void* aAddr, size_t aSize)
{
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 (!aAddr) {
aAddr = (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 + aSize <= end;
hint += kChunkSize) {
region = mmap((void*)hint,
aSize,
PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON,
-1,
0);
if (region != MAP_FAILED) {
if (((size_t)region + (aSize - 1)) & 0xffff800000000000) {
if (munmap(region, aSize)) {
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(aAddr, aSize, 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, aSize);
ret = nullptr;
}
// If the caller requested a specific memory location, verify that's what mmap
// returned.
else if (check_placement && ret != aAddr) {
#else
else if (aAddr && ret != aAddr) {
#endif
// We succeeded in mapping memory, but not in the right place.
pages_unmap(ret, aSize);
ret = nullptr;
}
if (ret) {
MozTagAnonymousMemory(ret, aSize, "jemalloc");
}
#if defined(__ia64__) || \
(defined(__sparc__) && defined(__arch64__) && defined(__linux__))
MOZ_ASSERT(!ret || (!check_placement && ret) ||
(check_placement && ret == aAddr));
#else
MOZ_ASSERT(!ret || (!aAddr && ret != aAddr) || (aAddr && ret == aAddr));
#endif
return ret;
}
#endif
#ifdef XP_DARWIN
#define VM_COPY_MIN (gPageSize * 32)
static inline void
pages_copy(void* dest, const void* src, size_t n)
{
MOZ_ASSERT((void*)((uintptr_t)dest & ~gPageSizeMask) == dest);
MOZ_ASSERT(n >= VM_COPY_MIN);
MOZ_ASSERT((void*)((uintptr_t)src & ~gPageSizeMask) == src);
vm_copy(
mach_task_self(), (vm_address_t)src, (vm_size_t)n, (vm_address_t)dest);
}
#endif
template<size_t Bits>
bool
AddressRadixTree<Bits>::Init()
{
mLock.Init();
mRoot = (void**)base_calloc(1 << kBitsAtLevel1, sizeof(void*));
return mRoot;
}
template<size_t Bits>
void**
AddressRadixTree<Bits>::GetSlot(void* aKey, bool aCreate)
{
uintptr_t key = reinterpret_cast<uintptr_t>(aKey);
uintptr_t subkey;
unsigned i, lshift, height, bits;
void** node;
void** child;
for (i = lshift = 0, height = kHeight, node = mRoot; i < height - 1;
i++, lshift += bits, node = child) {
bits = i ? kBitsPerLevel : kBitsAtLevel1;
subkey = (key << lshift) >> ((sizeof(void*) << 3) - bits);
child = (void**)node[subkey];
if (!child && aCreate) {
child = (void**)base_calloc(1 << kBitsPerLevel, sizeof(void*));
if (child) {
node[subkey] = child;
}
}
if (!child) {
return nullptr;
}
}
// node is a leaf, so it contains values rather than node
// pointers.
bits = i ? kBitsPerLevel : kBitsAtLevel1;
subkey = (key << lshift) >> ((sizeof(void*) << 3) - bits);
return &node[subkey];
}
template<size_t Bits>
void*
AddressRadixTree<Bits>::Get(void* aKey)
{
void* ret = nullptr;
void** slot = GetSlot(aKey);
if (slot) {
ret = *slot;
}
#ifdef MOZ_DEBUG
MutexAutoLock lock(mLock);
// 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.
if (!slot) {
// In case a slot has been created in the meantime.
slot = GetSlot(aKey);
}
if (slot) {
// The MutexAutoLock above should act as a memory barrier, forcing
// the compiler to emit a new read instruction for *slot.
MOZ_ASSERT(ret == *slot);
} else {
MOZ_ASSERT(ret == nullptr);
}
#endif
return ret;
}
template<size_t Bits>
bool
AddressRadixTree<Bits>::Set(void* aKey, void* aValue)
{
MutexAutoLock lock(mLock);
void** slot = GetSlot(aKey, /* create = */ true);
if (slot) {
*slot = aValue;
}
return slot;
}
// 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 XP_WIN
{
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 - gPageSize;
// 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 XP_LINUX
if (force_zero) {
memset(addr, 0, length);
}
#endif
#ifdef XP_WIN
// 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, kChunkSize - GetChunkOffsetForPtr(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, kChunkSize);
}
return force_zero;
#else
#ifdef XP_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(size_t aSize, size_t aAlignment, bool* aZeroed)
{
extent_node_t key;
size_t alloc_size = aSize + aAlignment - kChunkSize;
// Beware size_t wrap-around.
if (alloc_size < aSize) {
return nullptr;
}
key.mAddr = nullptr;
key.mSize = alloc_size;
chunks_mtx.Lock();
extent_node_t* node = gChunksBySize.SearchOrNext(&key);
if (!node) {
chunks_mtx.Unlock();
return nullptr;
}
size_t leadsize = ALIGNMENT_CEILING((uintptr_t)node->mAddr, aAlignment) -
(uintptr_t)node->mAddr;
MOZ_ASSERT(node->mSize >= leadsize + aSize);
size_t trailsize = node->mSize - leadsize - aSize;
void* ret = (void*)((uintptr_t)node->mAddr + leadsize);
ChunkType chunk_type = node->mChunkType;
if (aZeroed) {
*aZeroed = (chunk_type == ZEROED_CHUNK);
}
// Remove node from the tree.
gChunksBySize.Remove(node);
gChunksByAddress.Remove(node);
if (leadsize != 0) {
// Insert the leading space as a smaller chunk.
node->mSize = leadsize;
gChunksBySize.Insert(node);
gChunksByAddress.Insert(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.
chunks_mtx.Unlock();
node = base_node_alloc();
if (!node) {
chunk_dealloc(ret, aSize, chunk_type);
return nullptr;
}
chunks_mtx.Lock();
}
node->mAddr = (void*)((uintptr_t)(ret) + aSize);
node->mSize = trailsize;
node->mChunkType = chunk_type;
gChunksBySize.Insert(node);
gChunksByAddress.Insert(node);
node = nullptr;
}
gRecycledSize -= aSize;
chunks_mtx.Unlock();
if (node) {
base_node_dealloc(node);
}
#ifdef MALLOC_DECOMMIT
if (!pages_commit(ret, aSize)) {
return nullptr;
}
// pages_commit is guaranteed to zero the chunk.
if (aZeroed) {
*aZeroed = true;
}
#endif
return ret;
}
#ifdef XP_WIN
// 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 == kChunkSize)
#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 aSize, size_t aAlignment, bool aBase, bool* aZeroed)
{
void* ret = nullptr;
MOZ_ASSERT(aSize != 0);
MOZ_ASSERT((aSize & kChunkSizeMask) == 0);
MOZ_ASSERT(aAlignment != 0);
MOZ_ASSERT((aAlignment & kChunkSizeMask) == 0);
// Base allocations can't be fulfilled by recycling because of
// possible deadlock or infinite recursion.
if (CAN_RECYCLE(aSize) && !aBase) {
ret = chunk_recycle(aSize, aAlignment, aZeroed);
}
if (!ret) {
ret = chunk_alloc_mmap(aSize, aAlignment);
if (aZeroed) {
*aZeroed = true;
}
}
if (ret && !aBase) {
if (!gChunkRTree.Set(ret, ret)) {
chunk_dealloc(ret, aSize, UNKNOWN_CHUNK);
return nullptr;
}
}
MOZ_ASSERT(GetChunkOffsetForPtr(ret) == 0);
return ret;
}
static void
chunk_ensure_zero(void* aPtr, size_t aSize, bool aZeroed)
{
if (aZeroed == false) {
memset(aPtr, 0, aSize);
}
#ifdef MOZ_DEBUG
else {
size_t i;
size_t* p = (size_t*)(uintptr_t)aPtr;
for (i = 0; i < aSize / sizeof(size_t); i++) {
MOZ_ASSERT(p[i] == 0);
}
}
#endif
}
static void
chunk_record(void* aChunk, size_t aSize, ChunkType aType)
{
extent_node_t key;
if (aType != ZEROED_CHUNK) {
if (pages_purge(aChunk, aSize, aType == HUGE_CHUNK)) {
aType = 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.
UniqueBaseNode xnode(base_node_alloc());
// Use xprev to implement conditional deferred deallocation of prev.
UniqueBaseNode xprev;
// RAII deallocates xnode and xprev defined above after unlocking
// in order to avoid potential dead-locks
MutexAutoLock lock(chunks_mtx);
key.mAddr = (void*)((uintptr_t)aChunk + aSize);
extent_node_t* node = gChunksByAddress.SearchOrNext(&key);
// Try to coalesce forward.
if (node && node->mAddr == key.mAddr) {
// Coalesce chunk with the following address range. This does
// not change the position within gChunksByAddress, so only
// remove/insert from/into gChunksBySize.
gChunksBySize.Remove(node);
node->mAddr = aChunk;
node->mSize += aSize;
if (node->mChunkType != aType) {
node->mChunkType = RECYCLED_CHUNK;
}
gChunksBySize.Insert(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.
return;
}
node = xnode.release();
node->mAddr = aChunk;
node->mSize = aSize;
node->mChunkType = aType;
gChunksByAddress.Insert(node);
gChunksBySize.Insert(node);
}
// Try to coalesce backward.
extent_node_t* prev = gChunksByAddress.Prev(node);
if (prev && (void*)((uintptr_t)prev->mAddr + prev->mSize) == aChunk) {
// Coalesce chunk with the previous address range. This does
// not change the position within gChunksByAddress, so only
// remove/insert node from/into gChunksBySize.
gChunksBySize.Remove(prev);
gChunksByAddress.Remove(prev);
gChunksBySize.Remove(node);
node->mAddr = prev->mAddr;
node->mSize += prev->mSize;
if (node->mChunkType != prev->mChunkType) {
node->mChunkType = RECYCLED_CHUNK;
}
gChunksBySize.Insert(node);
xprev.reset(prev);
}
gRecycledSize += aSize;
}
static void
chunk_dealloc(void* aChunk, size_t aSize, ChunkType aType)
{
MOZ_ASSERT(aChunk);
MOZ_ASSERT(GetChunkOffsetForPtr(aChunk) == 0);
MOZ_ASSERT(aSize != 0);
MOZ_ASSERT((aSize & kChunkSizeMask) == 0);
gChunkRTree.Unset(aChunk);
if (CAN_RECYCLE(aSize)) {
size_t recycled_so_far = gRecycledSize;
// In case some race condition put us above the limit.
if (recycled_so_far < gRecycleLimit) {
size_t recycle_remaining = gRecycleLimit - recycled_so_far;
size_t to_recycle;
if (aSize > recycle_remaining) {
to_recycle = recycle_remaining;
// Drop pages that would overflow the recycle limit
pages_trim(aChunk, aSize, 0, to_recycle);
} else {
to_recycle = aSize;
}
chunk_record(aChunk, to_recycle, aType);
return;
}
}
pages_unmap(aChunk, aSize);
}
#undef CAN_RECYCLE
// End chunk management functions.
// ***************************************************************************
// Begin arena.
static inline arena_t*
thread_local_arena(bool enabled)
{
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 =
gArenas.CreateArena(/* IsPrivate = */ false, /* Params = */ nullptr);
} else {
arena = gArenas.GetDefault();
}
thread_arena.set(arena);
return arena;
}
template<>
inline void
MozJemalloc::jemalloc_thread_local_arena(bool aEnabled)
{
if (malloc_init()) {
thread_local_arena(aEnabled);
}
}
// Choose an arena based on a per-thread value.
static inline arena_t*
choose_arena(size_t size)
{
arena_t* ret = nullptr;
// 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.
if (size > kMaxQuantumClass) {
// Force the default arena for larger allocations.
ret = gArenas.GetDefault();
} else {
// Check TLS to see if our thread has requested a pinned arena.
ret = thread_arena.get();
if (!ret) {
// Nothing in TLS. Pin this thread to the default arena.
ret = thread_local_arena(false);
}
}
MOZ_DIAGNOSTIC_ASSERT(ret);
return ret;
}
static inline void*
arena_run_reg_alloc(arena_run_t* run, arena_bin_t* bin)
{
void* ret;
unsigned i, mask, bit, regind;
MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
MOZ_ASSERT(run->mRegionsMinElement < bin->mRunNumRegionsMask);
// Move the first check outside the loop, so that run->mRegionsMinElement can
// be updated unconditionally, without the possibility of updating it
// multiple times.
i = run->mRegionsMinElement;
mask = run->mRegionsMask[i];
if (mask != 0) {
// Usable allocation found.
bit = CountTrailingZeroes32(mask);
regind = ((i << (LOG2(sizeof(int)) + 3)) + bit);
MOZ_ASSERT(regind < bin->mRunNumRegions);
ret = (void*)(((uintptr_t)run) + bin->mRunFirstRegionOffset +
(bin->mSizeClass * regind));
// Clear bit.
mask ^= (1U << bit);
run->mRegionsMask[i] = mask;
return ret;
}
for (i++; i < bin->mRunNumRegionsMask; i++) {
mask = run->mRegionsMask[i];
if (mask != 0) {
// Usable allocation found.
bit = CountTrailingZeroes32(mask);
regind = ((i << (LOG2(sizeof(int)) + 3)) + bit);
MOZ_ASSERT(regind < bin->mRunNumRegions);
ret = (void*)(((uintptr_t)run) + bin->mRunFirstRegionOffset +
(bin->mSizeClass * regind));
// Clear bit.
mask ^= (1U << bit);
run->mRegionsMask[i] = mask;
// Make a note that nothing before this element
// contains a free region.
run->mRegionsMinElement = 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 / kQuantum) - 3]) >> SIZE_INV_SHIFT
#define SIZE_INV_SHIFT 21
#define SIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s * kQuantum)) + 1)
// clang-format off
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)
};
// clang-format on
unsigned diff, regind, elm, bit;
MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
static_assert(((sizeof(size_invs)) / sizeof(unsigned)) + 3 >=
kNumQuantumClasses,
"size_invs doesn't have enough values");
// 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->mRunFirstRegionOffset);
if (mozilla::IsPowerOfTwo(size)) {
regind = diff >> FloorLog2(size);
} else if (size <= ((sizeof(size_invs) / sizeof(unsigned)) * kQuantum) + 2) {
regind = size_invs[(size / kQuantum) - 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->mRunNumRegions);
elm = regind >> (LOG2(sizeof(int)) + 3);
if (elm < run->mRegionsMinElement) {
run->mRegionsMinElement = elm;
}
bit = regind - (elm << (LOG2(sizeof(int)) + 3));
MOZ_RELEASE_ASSERT((run->mRegionsMask[elm] & (1U << bit)) == 0,
"Double-free?");
run->mRegionsMask[elm] |= (1U << bit);
#undef SIZE_INV
#undef SIZE_INV_SHIFT
}
bool
arena_t::SplitRun(arena_run_t* aRun, size_t aSize, bool aLarge, bool aZero)
{
arena_chunk_t* chunk;
size_t old_ndirty, run_ind, total_pages, need_pages, rem_pages, i;
chunk = GetChunkForPtr(aRun);
old_ndirty = chunk->ndirty;
run_ind = (unsigned)((uintptr_t(aRun) - uintptr_t(chunk)) >> gPageSize2Pow);
total_pages = (chunk->map[run_ind].bits & ~gPageSizeMask) >> gPageSize2Pow;
need_pages = (aSize >> gPageSize2Pow);
MOZ_ASSERT(need_pages > 0);
MOZ_ASSERT(need_pages <= total_pages);
rem_pages = total_pages - 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
bool committed = pages_commit(
(void*)(uintptr_t(chunk) + ((run_ind + i) << gPageSize2Pow)),
j << gPageSize2Pow);
// pages_commit zeroes pages, so mark them as such if it succeeded.
// That's checked further below to avoid manually zeroing the pages.
for (size_t k = 0; k < j; k++) {
chunk->map[run_ind + i + k].bits |=
committed ? CHUNK_MAP_ZEROED : CHUNK_MAP_DECOMMITTED;
}
if (!committed) {
return false;
}
#endif
mStats.committed += j;
}
}
mRunsAvail.Remove(&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 << gPageSize2Pow) |
(chunk->map[run_ind + need_pages].bits & gPageSizeMask);
chunk->map[run_ind + total_pages - 1].bits =
(rem_pages << gPageSize2Pow) |
(chunk->map[run_ind + total_pages - 1].bits & gPageSizeMask);
mRunsAvail.Insert(&chunk->map[run_ind + need_pages]);
}
for (i = 0; i < need_pages; i++) {
// Zero if necessary.
if (aZero) {
if ((chunk->map[run_ind + i].bits & CHUNK_MAP_ZEROED) == 0) {
memset((void*)(uintptr_t(chunk) + ((run_ind + i) << gPageSize2Pow)),
0,
gPageSize);
// CHUNK_MAP_ZEROED is cleared below.
}
}
// Update dirty page accounting.
if (chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY) {
chunk->ndirty--;
mNumDirty--;
// CHUNK_MAP_DIRTY is cleared below.
}
// Initialize the chunk map.
if (aLarge) {
chunk->map[run_ind + i].bits = CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
} else {
chunk->map[run_ind + i].bits = size_t(aRun) | 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 (aLarge) {
chunk->map[run_ind].bits |= aSize;
}
if (chunk->ndirty == 0 && old_ndirty > 0) {
mChunksDirty.Remove(chunk);
}
return true;
}
void
arena_t::InitChunk(arena_chunk_t* aChunk, bool aZeroed)
{
size_t i;
// WARNING: The following relies on !aZeroed 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 =
aZeroed ? CHUNK_MAP_DECOMMITTED | CHUNK_MAP_ZEROED : CHUNK_MAP_MADVISED;
mStats.mapped += kChunkSize;
aChunk->arena = this;
// Claim that no pages are in use, since the header is merely overhead.
aChunk->ndirty = 0;
// Initialize the map to contain one maximal free untouched run.
#ifdef MALLOC_DECOMMIT
arena_run_t* run =
(arena_run_t*)(uintptr_t(aChunk) + (gChunkHeaderNumPages << gPageSize2Pow));
#endif
for (i = 0; i < gChunkHeaderNumPages; i++) {
aChunk->map[i].bits = 0;
}
aChunk->map[i].bits = gMaxLargeClass | flags;
for (i++; i < gChunkNumPages - 1; i++) {
aChunk->map[i].bits = flags;
}
aChunk->map[gChunkNumPages - 1].bits = gMaxLargeClass | flags;
#ifdef MALLOC_DECOMMIT
// Start out decommitted, in order to force a closer correspondence
// between dirty pages and committed untouched pages.
pages_decommit(run, gMaxLargeClass);
#endif
mStats.committed += gChunkHeaderNumPages;
// Insert the run into the tree of available runs.
mRunsAvail.Insert(&aChunk->map[gChunkHeaderNumPages]);
#ifdef MALLOC_DOUBLE_PURGE
new (&aChunk->chunks_madvised_elem) DoublyLinkedListElement<arena_chunk_t>();
#endif
}
void
arena_t::DeallocChunk(arena_chunk_t* aChunk)
{
if (mSpare) {
if (mSpare->ndirty > 0) {
aChunk->arena->mChunksDirty.Remove(mSpare);
mNumDirty -= mSpare->ndirty;
mStats.committed -= mSpare->ndirty;
}
#ifdef MALLOC_DOUBLE_PURGE
if (mChunksMAdvised.ElementProbablyInList(mSpare)) {
mChunksMAdvised.remove(mSpare);
}
#endif
chunk_dealloc((void*)mSpare, kChunkSize, ARENA_CHUNK);
mStats.mapped -= kChunkSize;
mStats.committed -= gChunkHeaderNumPages;
}
// Remove run from the tree of available runs, so that the arena does not use
// it. Dirty page flushing only uses the tree of dirty chunks, so leaving this
// chunk in the chunks_* trees is sufficient for that purpose.
mRunsAvail.Remove(&aChunk->map[gChunkHeaderNumPages]);
mSpare = aChunk;
}
arena_run_t*
arena_t::AllocRun(size_t aSize, bool aLarge, bool aZero)
{
arena_run_t* run;
arena_chunk_map_t* mapelm;
arena_chunk_map_t key;
MOZ_ASSERT(aSize <= gMaxLargeClass);
MOZ_ASSERT((aSize & gPageSizeMask) == 0);
// Search the arena's chunks for the lowest best fit.
key.bits = aSize | CHUNK_MAP_KEY;
mapelm = mRunsAvail.SearchOrNext(&key);
if (mapelm) {
arena_chunk_t* chunk = GetChunkForPtr(mapelm);
size_t pageind =
(uintptr_t(mapelm) - uintptr_t(chunk->map)) / sizeof(arena_chunk_map_t);
run = (arena_run_t*)(uintptr_t(chunk) + (pageind << gPageSize2Pow));
} else if (mSpare) {
// Use the spare.
arena_chunk_t* chunk = mSpare;
mSpare = nullptr;
run = (arena_run_t*)(uintptr_t(chunk) +
(gChunkHeaderNumPages << gPageSize2Pow));
// Insert the run into the tree of available runs.
mRunsAvail.Insert(&chunk->map[gChunkHeaderNumPages]);
} else {
// No usable runs. Create a new chunk from which to allocate
// the run.
bool zeroed;
arena_chunk_t* chunk =
(arena_chunk_t*)chunk_alloc(kChunkSize, kChunkSize, false, &zeroed);
if (!chunk) {
return nullptr;
}
InitChunk(chunk, zeroed);
run = (arena_run_t*)(uintptr_t(chunk) +
(gChunkHeaderNumPages << gPageSize2Pow));
}
// Update page map.
return SplitRun(run, aSize, aLarge, aZero) ? run : nullptr;
}
void
arena_t::Purge(bool aAll)
{
arena_chunk_t* chunk;
size_t i, npages;
// If all is set purge all dirty pages.
size_t dirty_max = aAll ? 1 : mMaxDirty;
#ifdef MOZ_DEBUG
size_t ndirty = 0;
for (auto chunk : mChunksDirty.iter()) {
ndirty += chunk->ndirty;
}
MOZ_ASSERT(ndirty == mNumDirty);
#endif
MOZ_DIAGNOSTIC_ASSERT(aAll || (mNumDirty > mMaxDirty));
// 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 (mNumDirty > (dirty_max >> 1)) {
#ifdef MALLOC_DOUBLE_PURGE
bool madvised = false;
#endif
chunk = mChunksDirty.Last();
MOZ_DIAGNOSTIC_ASSERT(chunk);
for (i = gChunkNumPages - 1; chunk->ndirty > 0; i--) {
MOZ_DIAGNOSTIC_ASSERT(i >= gChunkHeaderNumPages);
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 > gChunkHeaderNumPages &&
(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;
mNumDirty -= npages;
#ifdef MALLOC_DECOMMIT
pages_decommit((void*)(uintptr_t(chunk) + (i << gPageSize2Pow)),
(npages << gPageSize2Pow));
#endif
mStats.committed -= npages;
#ifndef MALLOC_DECOMMIT
madvise((void*)(uintptr_t(chunk) + (i << gPageSize2Pow)),
(npages << gPageSize2Pow),
MADV_FREE);
#ifdef MALLOC_DOUBLE_PURGE
madvised = true;
#endif
#endif
if (mNumDirty <= (dirty_max >> 1)) {
break;
}
}
}
if (chunk->ndirty == 0) {
mChunksDirty.Remove(chunk);
}
#ifdef MALLOC_DOUBLE_PURGE
if (madvised) {
// The chunk might already be in the list, but this
// makes sure it's at the front.
if (mChunksMAdvised.ElementProbablyInList(chunk)) {
mChunksMAdvised.remove(chunk);
}
mChunksMAdvised.pushFront(chunk);
}
#endif
}
}
void
arena_t::DallocRun(arena_run_t* aRun, bool aDirty)
{
arena_chunk_t* chunk;
size_t size, run_ind, run_pages;
chunk = GetChunkForPtr(aRun);
run_ind = (size_t)((uintptr_t(aRun) - uintptr_t(chunk)) >> gPageSize2Pow);
MOZ_DIAGNOSTIC_ASSERT(run_ind >= gChunkHeaderNumPages);
MOZ_DIAGNOSTIC_ASSERT(run_ind < gChunkNumPages);
if ((chunk->map[run_ind].bits & CHUNK_MAP_LARGE) != 0) {
size = chunk->map[run_ind].bits & ~gPageSizeMask;
} else {
size = aRun->mBin->mRunSize;
}
run_pages = (size >> gPageSize2Pow);
// Mark pages as unallocated in the chunk map.
if (aDirty) {
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) {
mChunksDirty.Insert(chunk);
}
chunk->ndirty += run_pages;
mNumDirty += 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 & gPageSizeMask);
chunk->map[run_ind + run_pages - 1].bits =
size | (chunk->map[run_ind + run_pages - 1].bits & gPageSizeMask);
// Try to coalesce forward.
if (run_ind + run_pages < gChunkNumPages &&
(chunk->map[run_ind + run_pages].bits & CHUNK_MAP_ALLOCATED) == 0) {
size_t nrun_size = chunk->map[run_ind + run_pages].bits & ~gPageSizeMask;
// Remove successor from tree of available runs; the coalesced run is
// inserted later.
mRunsAvail.Remove(&chunk->map[run_ind + run_pages]);
size += nrun_size;
run_pages = size >> gPageSize2Pow;
MOZ_DIAGNOSTIC_ASSERT(
(chunk->map[run_ind + run_pages - 1].bits & ~gPageSizeMask) == nrun_size);
chunk->map[run_ind].bits =
size | (chunk->map[run_ind].bits & gPageSizeMask);
chunk->map[run_ind + run_pages - 1].bits =
size | (chunk->map[run_ind + run_pages - 1].bits & gPageSizeMask);
}
// Try to coalesce backward.
if (run_ind > gChunkHeaderNumPages &&
(chunk->map[run_ind - 1].bits & CHUNK_MAP_ALLOCATED) == 0) {
size_t prun_size = chunk->map[run_ind - 1].bits & ~gPageSizeMask;
run_ind -= prun_size >> gPageSize2Pow;
// Remove predecessor from tree of available runs; the coalesced run is
// inserted later.
mRunsAvail.Remove(&chunk->map[run_ind]);
size += prun_size;
run_pages = size >> gPageSize2Pow;
MOZ_DIAGNOSTIC_ASSERT((chunk->map[run_ind].bits & ~gPageSizeMask) ==
prun_size);
chunk->map[run_ind].bits =
size | (chunk->map[run_ind].bits & gPageSizeMask);
chunk->map[run_ind + run_pages - 1].bits =
size | (chunk->map[run_ind + run_pages - 1].bits & gPageSizeMask);
}
// Insert into tree of available runs, now that coalescing is complete.
mRunsAvail.Insert(&chunk->map[run_ind]);
// Deallocate chunk if it is now completely unused.
if ((chunk->map[gChunkHeaderNumPages].bits &
(~gPageSizeMask | CHUNK_MAP_ALLOCATED)) == gMaxLargeClass) {
DeallocChunk(chunk);
}
// Enforce mMaxDirty.
if (mNumDirty > mMaxDirty) {
Purge(false);
}
}
void
arena_t::TrimRunHead(arena_chunk_t* aChunk,
arena_run_t* aRun,
size_t aOldSize,
size_t aNewSize)
{
size_t pageind = (uintptr_t(aRun) - uintptr_t(aChunk)) >> gPageSize2Pow;
size_t head_npages = (aOldSize - aNewSize) >> gPageSize2Pow;
MOZ_ASSERT(aOldSize > aNewSize);
// Update the chunk map so that arena_t::RunDalloc() can treat the
// leading run as separately allocated.
aChunk->map[pageind].bits =
(aOldSize - aNewSize) | CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
aChunk->map[pageind + head_npages].bits =
aNewSize | CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
DallocRun(aRun, false);
}
void
arena_t::TrimRunTail(arena_chunk_t* aChunk,
arena_run_t* aRun,
size_t aOldSize,
size_t aNewSize,
bool aDirty)
{
size_t pageind = (uintptr_t(aRun) - uintptr_t(aChunk)) >> gPageSize2Pow;
size_t npages = aNewSize >> gPageSize2Pow;
MOZ_ASSERT(aOldSize > aNewSize);
// Update the chunk map so that arena_t::RunDalloc() can treat the
// trailing run as separately allocated.
aChunk->map[pageind].bits = aNewSize | CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
aChunk->map[pageind + npages].bits =
(aOldSize - aNewSize) | CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
DallocRun((arena_run_t*)(uintptr_t(aRun) + aNewSize), aDirty);
}
arena_run_t*
arena_t::GetNonFullBinRun(arena_bin_t* aBin)
{
arena_chunk_map_t* mapelm;
arena_run_t* run;
unsigned i, remainder;
// Look for a usable run.
mapelm = aBin->mNonFullRuns.First();
if (mapelm) {
// run is guaranteed to have available space.
aBin->mNonFullRuns.Remove(mapelm);
run = (arena_run_t*)(mapelm->bits & ~gPageSizeMask);
return run;
}
// No existing runs have any space available.
// Allocate a new run.
run = AllocRun(aBin->mRunSize, false, false);
if (!run) {
return nullptr;
}
// Don't initialize if a race in arena_t::RunAlloc() allowed an existing
// run to become usable.
if (run == aBin->mCurrentRun) {
return run;
}
// Initialize run internals.
run->mBin = aBin;
for (i = 0; i < aBin->mRunNumRegionsMask - 1; i++) {
run->mRegionsMask[i] = UINT_MAX;
}
remainder = aBin->mRunNumRegions & ((1U << (LOG2(sizeof(int)) + 3)) - 1);
if (remainder == 0) {
run->mRegionsMask[i] = UINT_MAX;
} else {
// The last element has spare bits that need to be unset.
run->mRegionsMask[i] =
(UINT_MAX >> ((1U << (LOG2(sizeof(int)) + 3)) - remainder));
}
run->mRegionsMinElement = 0;
run->mNumFree = aBin->mRunNumRegions;
#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
run->mMagic = ARENA_RUN_MAGIC;
#endif
aBin->mNumRuns++;
return run;
}
void
arena_bin_t::Init(SizeClass aSizeClass)
{
size_t try_run_size;
unsigned try_nregs, try_mask_nelms, try_reg0_offset;
// Size of the run header, excluding mRegionsMask.
static const size_t kFixedHeaderSize = offsetof(arena_run_t, mRegionsMask);
MOZ_ASSERT(aSizeClass.Size() <= gMaxBinClass);
try_run_size = gPageSize;
mCurrentRun = nullptr;
mNonFullRuns.Init();
mSizeClass = aSizeClass.Size();
mNumRuns = 0;
// mRunSize expansion loop.
while (true) {
try_nregs = ((try_run_size - kFixedHeaderSize) / mSizeClass) +
1; // Counter-act try_nregs-- in loop.
// 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.
do {
try_nregs--;
try_mask_nelms =
(try_nregs >> (LOG2(sizeof(int)) + 3)) +
((try_nregs & ((1U << (LOG2(sizeof(int)) + 3)) - 1)) ? 1 : 0);
try_reg0_offset = try_run_size - (try_nregs * mSizeClass);
} while (kFixedHeaderSize + (sizeof(unsigned) * try_mask_nelms) >
try_reg0_offset);
// Don't allow runs larger than the largest possible large size class.
if (try_run_size > gMaxLargeClass) {
break;
}
// Try to keep the run overhead below kRunOverhead.
if (Fraction(try_reg0_offset, try_run_size) <= kRunOverhead) {
break;
}
// If the overhead is larger than the size class, it means the size class
// is small and doesn't align very well with the header. It's desirable to
// have smaller run sizes for them, so relax the overhead requirement.
if (try_reg0_offset > mSizeClass) {
if (Fraction(try_reg0_offset, try_run_size) <= kRunRelaxedOverhead) {
break;
}
}
// The run header includes one bit per region of the given size. For sizes
// small enough, the number of regions is large enough that growing the run
// size barely moves the needle for the overhead because of all those bits.
// For example, for a size of 8 bytes, adding 4KiB to the run size adds
// close to 512 bits to the header, which is 64 bytes.
// With such overhead, there is no way to get to the wanted overhead above,
// so we give up if the required size for mRegionsMask more than doubles the
// size of the run header.
if (try_mask_nelms * sizeof(unsigned) >= kFixedHeaderSize) {
break;
}
// Try more aggressive settings.
try_run_size += gPageSize;
}
MOZ_ASSERT(kFixedHeaderSize + (sizeof(unsigned) * try_mask_nelms) <=
try_reg0_offset);
MOZ_ASSERT((try_mask_nelms << (LOG2(sizeof(int)) + 3)) >= try_nregs);
// Copy final settings.
mRunSize = try_run_size;
mRunNumRegions = try_nregs;
mRunNumRegionsMask = try_mask_nelms;
mRunFirstRegionOffset = try_reg0_offset;
}
void*
arena_t::MallocSmall(size_t aSize, bool aZero)
{
void* ret;
arena_bin_t* bin;
arena_run_t* run;
SizeClass sizeClass(aSize);
aSize = sizeClass.Size();
switch (sizeClass.Type()) {
case SizeClass::Tiny:
bin = &mBins[FloorLog2(aSize / kMinTinyClass)];
break;
case SizeClass::Quantum:
bin = &mBins[kNumTinyClasses + (aSize / kQuantum) - 1];
break;
case SizeClass::SubPage:
bin = &mBins[kNumTinyClasses + kNumQuantumClasses +
(FloorLog2(aSize / kMaxQuantumClass) - 1)];
break;
default:
MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Unexpected size class type");
}
MOZ_DIAGNOSTIC_ASSERT(aSize == bin->mSizeClass);
{
MutexAutoLock lock(mLock);
run = bin->mCurrentRun;
if (MOZ_UNLIKELY(!run || run->mNumFree == 0)) {
run = bin->mCurrentRun = GetNonFullBinRun(bin);
}
if (MOZ_UNLIKELY(!run)) {
return nullptr;
}
MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
MOZ_DIAGNOSTIC_ASSERT(run->mNumFree > 0);
ret = arena_run_reg_alloc(run, bin);
MOZ_DIAGNOSTIC_ASSERT(ret);
run->mNumFree--;
if (!ret) {
return nullptr;
}
mStats.allocated_small += aSize;
}
if (!aZero) {
ApplyZeroOrJunk(ret, aSize);
} else {
memset(ret, 0, aSize);
}
return ret;
}
void*
arena_t::MallocLarge(size_t aSize, bool aZero)
{
void* ret;
// Large allocation.
aSize = PAGE_CEILING(aSize);
{
MutexAutoLock lock(mLock);
ret = AllocRun(aSize, true, aZero);
if (!ret) {
return nullptr;
}
mStats.allocated_large += aSize;
}
if (!aZero) {
ApplyZeroOrJunk(ret, aSize);
}
return ret;
}
void*
arena_t::Malloc(size_t aSize, bool aZero)
{
MOZ_DIAGNOSTIC_ASSERT(mMagic == ARENA_MAGIC);
MOZ_ASSERT(aSize != 0);
if (aSize <= gMaxBinClass) {
return MallocSmall(aSize, aZero);
}
if (aSize <= gMaxLargeClass) {
return MallocLarge(aSize, aZero);
}
return MallocHuge(aSize, aZero);
}
// Only handles large allocations that require more than page alignment.
void*
arena_t::PallocLarge(size_t aAlignment, size_t aSize, size_t aAllocSize)
{
void* ret;
size_t offset;
arena_chunk_t* chunk;
MOZ_ASSERT((aSize & gPageSizeMask) == 0);
MOZ_ASSERT((aAlignment & gPageSizeMask) == 0);
{
MutexAutoLock lock(mLock);
ret = AllocRun(aAllocSize, true, false);
if (!ret) {
return nullptr;
}
chunk = GetChunkForPtr(ret);
offset = uintptr_t(ret) & (aAlignment - 1);
MOZ_ASSERT((offset & gPageSizeMask) == 0);
MOZ_ASSERT(offset < aAllocSize);
if (offset == 0) {
TrimRunTail(chunk, (arena_run_t*)ret, aAllocSize, aSize, false);
} else {
size_t leadsize, trailsize;
leadsize = aAlignment - offset;
if (leadsize > 0) {
TrimRunHead(
chunk, (arena_run_t*)ret, aAllocSize, aAllocSize - leadsize);
ret = (void*)(uintptr_t(ret) + leadsize);
}
trailsize = aAllocSize - leadsize - aSize;
if (trailsize != 0) {
// Trim trailing space.
MOZ_ASSERT(trailsize < aAllocSize);
TrimRunTail(chunk, (arena_run_t*)ret, aSize + trailsize, aSize, false);
}
}
mStats.allocated_large += aSize;
}
ApplyZeroOrJunk(ret, aSize);
return ret;
}
void*
arena_t::Palloc(size_t aAlignment, size_t aSize)
{
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(aSize, aAlignment);
// (ceil_size < aSize) protects against the combination of maximal
// alignment and size greater than maximal alignment.
if (ceil_size < aSize) {
// size_t overflow.
return nullptr;
}
if (ceil_size <= gPageSize ||
(aAlignment <= gPageSize && ceil_size <= gMaxLargeClass)) {
ret = Malloc(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.
aAlignment = PAGE_CEILING(aAlignment);
ceil_size = PAGE_CEILING(aSize);
// (ceil_size < aSize) protects against very large sizes within
// pagesize of SIZE_T_MAX.
//
// (ceil_size + aAlignment < 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 < aSize || ceil_size + aAlignment < 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 >= aAlignment) {
run_size = ceil_size + aAlignment - gPageSize;
} else {
// It is possible that (aAlignment << 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 = (aAlignment << 1) - gPageSize;
}
if (run_size <= gMaxLargeClass) {
ret = PallocLarge(aAlignment, ceil_size, run_size);
} else if (aAlignment <= kChunkSize) {
ret = MallocHuge(ceil_size, false);
} else {
ret = PallocHuge(ceil_size, aAlignment, false);
}
}
MOZ_ASSERT((uintptr_t(ret) & (aAlignment - 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(GetChunkOffsetForPtr(ptr) != 0);
chunk = GetChunkForPtr(ptr);
pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> gPageSize2Pow);
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 & ~gPageSizeMask);
MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
ret = run->mBin->mSizeClass;
} else {
ret = mapbits & ~gPageSizeMask;
MOZ_DIAGNOSTIC_ASSERT(ret != 0);
}
return ret;
}
class AllocInfo
{
public:
template<bool Validate = false>
static inline AllocInfo Get(const void* aPtr)
{
// If the allocator is not initialized, the pointer can't belong to it.
if (Validate && malloc_initialized == false) {
return AllocInfo();
}
auto chunk = GetChunkForPtr(aPtr);
if (Validate) {
if (!chunk || !gChunkRTree.Get(chunk)) {
return AllocInfo();
}
}
if (chunk != aPtr) {
MOZ_DIAGNOSTIC_ASSERT(chunk->arena->mMagic == ARENA_MAGIC);
return AllocInfo(arena_salloc(aPtr), chunk);
}
extent_node_t key;
// Huge allocation
key.mAddr = chunk;
MutexAutoLock lock(huge_mtx);
extent_node_t* node = huge.Search(&key);
if (Validate && !node) {
return AllocInfo();
}
return AllocInfo(node->mSize, node);
}
// 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 AllocInfo GetValidated(const void* aPtr)
{
return Get<true>(aPtr);
}
AllocInfo()
: mSize(0)
, mChunk(nullptr)
{
}
explicit AllocInfo(size_t aSize, arena_chunk_t* aChunk)
: mSize(aSize)
, mChunk(aChunk)
{
MOZ_ASSERT(mSize <= gMaxLargeClass);
}
explicit AllocInfo(size_t aSize, extent_node_t* aNode)
: mSize(aSize)
, mNode(aNode)
{
MOZ_ASSERT(mSize > gMaxLargeClass);
}
size_t Size() { return mSize; }
arena_t* Arena()
{
return (mSize <= gMaxLargeClass) ? mChunk->arena : mNode->mArena;
}
private:
size_t mSize;
union {
// Pointer to the chunk associated with the allocation for small
// and large allocations.
arena_chunk_t* mChunk;
// Pointer to the extent node for huge allocations.
extent_node_t* mNode;
};
};
template<>
inline void
MozJemalloc::jemalloc_ptr_info(const void* aPtr, jemalloc_ptr_info_t* aInfo)
{
arena_chunk_t* chunk = GetChunkForPtr(aPtr);
// Is the pointer null, or within one chunk's size of null?
// Alternatively, if the allocator is not initialized yet, the pointer
// can't be known.
if (!chunk || !malloc_initialized) {
*aInfo = { TagUnknown, nullptr, 0 };
return;
}
// Look for huge allocations before looking for |chunk| in gChunkRTree.
// This is necessary because |chunk| won't be in gChunkRTree if it's
// the second or subsequent chunk in a huge allocation.
extent_node_t* node;
extent_node_t key;
{
MutexAutoLock lock(huge_mtx);
key.mAddr = const_cast<void*>(aPtr);
node =
reinterpret_cast<RedBlackTree<extent_node_t, ExtentTreeBoundsTrait>*>(
&huge)
->Search(&key);
if (node) {
*aInfo = { TagLiveHuge, node->mAddr, node->mSize };
return;
}
}
// It's not a huge allocation. Check if we have a known chunk.
if (!gChunkRTree.Get(chunk)) {
*aInfo = { TagUnknown, nullptr, 0 };
return;
}
MOZ_DIAGNOSTIC_ASSERT(chunk->arena->mMagic == ARENA_MAGIC);
// Get the page number within the chunk.
size_t pageind = (((uintptr_t)aPtr - (uintptr_t)chunk) >> gPageSize2Pow);
if (pageind < gChunkHeaderNumPages) {
// Within the chunk header.
*aInfo = { TagUnknown, nullptr, 0 };
return;
}
size_t mapbits = chunk->map[pageind].bits;
if (!(mapbits & CHUNK_MAP_ALLOCATED)) {
PtrInfoTag tag = TagFreedPageDirty;
if (mapbits & CHUNK_MAP_DIRTY) {
tag = TagFreedPageDirty;
} else if (mapbits & CHUNK_MAP_DECOMMITTED) {
tag = TagFreedPageDecommitted;
} else if (mapbits & CHUNK_MAP_MADVISED) {
tag = TagFreedPageMadvised;
} else if (mapbits & CHUNK_MAP_ZEROED) {
tag = TagFreedPageZeroed;
} else {
MOZ_CRASH();
}
void* pageaddr = (void*)(uintptr_t(aPtr) & ~gPageSizeMask);
*aInfo = { tag, pageaddr, gPageSize };
return;
}
if (mapbits & CHUNK_MAP_LARGE) {
// It's a large allocation. Only the first page of a large
// allocation contains its size, so if the address is not in
// the first page, scan back to find the allocation size.
size_t size;
while (true) {
size = mapbits & ~gPageSizeMask;
if (size != 0) {
break;
}
// The following two return paths shouldn't occur in
// practice unless there is heap corruption.
pageind--;
MOZ_DIAGNOSTIC_ASSERT(pageind >= gChunkHeaderNumPages);
if (pageind < gChunkHeaderNumPages) {
*aInfo = { TagUnknown, nullptr, 0 };
return;
}
mapbits = chunk->map[pageind].bits;
MOZ_DIAGNOSTIC_ASSERT(mapbits & CHUNK_MAP_LARGE);
if (!(mapbits & CHUNK_MAP_LARGE)) {
*aInfo = { TagUnknown, nullptr, 0 };
return;
}
}
void* addr = ((char*)chunk) + (pageind << gPageSize2Pow);
*aInfo = { TagLiveLarge, addr, size };
return;
}
// It must be a small allocation.
auto run = (arena_run_t*)(mapbits & ~gPageSizeMask);
MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
// The allocation size is stored in the run metadata.
size_t size = run->mBin->mSizeClass;
// Address of the first possible pointer in the run after its headers.
uintptr_t reg0_addr = (uintptr_t)run + run->mBin->mRunFirstRegionOffset;
if (aPtr < (void*)reg0_addr) {
// In the run header.
*aInfo = { TagUnknown, nullptr, 0 };
return;
}
// Position in the run.
unsigned regind = ((uintptr_t)aPtr - reg0_addr) / size;
// Pointer to the allocation's base address.
void* addr = (void*)(reg0_addr + regind * size);
// Check if the allocation has been freed.
unsigned elm = regind >> (LOG2(sizeof(int)) + 3);
unsigned bit = regind - (elm << (LOG2(sizeof(int)) + 3));
PtrInfoTag tag =
((run->mRegionsMask[elm] & (1U << bit))) ? TagFreedSmall : TagLiveSmall;
*aInfo = { tag, addr, size };
}
namespace Debug {
// Helper for debuggers. We don't want it to be inlined and optimized out.
MOZ_NEVER_INLINE jemalloc_ptr_info_t*
jemalloc_ptr_info(const void* aPtr)
{
static jemalloc_ptr_info_t info;
MozJemalloc::jemalloc_ptr_info(aPtr, &info);
return &info;
}
}
void
arena_t::DallocSmall(arena_chunk_t* aChunk,
void* aPtr,
arena_chunk_map_t* aMapElm)
{
arena_run_t* run;
arena_bin_t* bin;
size_t size;
run = (arena_run_t*)(aMapElm->bits & ~gPageSizeMask);
MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
bin = run->mBin;
size = bin->mSizeClass;
MOZ_DIAGNOSTIC_ASSERT(uintptr_t(aPtr) >=
uintptr_t(run) + bin->mRunFirstRegionOffset);
MOZ_DIAGNOSTIC_ASSERT(
(uintptr_t(aPtr) - (uintptr_t(run) + bin->mRunFirstRegionOffset)) % size ==
0);
memset(aPtr, kAllocPoison, size);
arena_run_reg_dalloc(run, bin, aPtr, size);
run->mNumFree++;
if (run->mNumFree == bin->mRunNumRegions) {
// Deallocate run.
if (run == bin->mCurrentRun) {
bin->mCurrentRun = nullptr;
} else if (bin->mRunNumRegions != 1) {
size_t run_pageind =
(uintptr_t(run) - uintptr_t(aChunk)) >> gPageSize2Pow;
arena_chunk_map_t* run_mapelm = &aChunk->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(bin->mNonFullRuns.Search(run_mapelm) == run_mapelm);
bin->mNonFullRuns.Remove(run_mapelm);
}
#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
run->mMagic = 0;
#endif
DallocRun(run, true);
bin->mNumRuns--;
} else if (run->mNumFree == 1 && run != bin->mCurrentRun) {
// Make sure that bin->mCurrentRun always refers to the lowest
// non-full run, if one exists.
if (!bin->mCurrentRun) {
bin->mCurrentRun = run;
} else if (uintptr_t(run) < uintptr_t(bin->mCurrentRun)) {
// Switch mCurrentRun.
if (bin->mCurrentRun->mNumFree > 0) {
arena_chunk_t* runcur_chunk = GetChunkForPtr(bin->mCurrentRun);
size_t runcur_pageind =
(uintptr_t(bin->mCurrentRun) - uintptr_t(runcur_chunk)) >>
gPageSize2Pow;
arena_chunk_map_t* runcur_mapelm = &runcur_chunk->map[runcur_pageind];
// Insert runcur.
MOZ_DIAGNOSTIC_ASSERT(!bin->mNonFullRuns.Search(runcur_mapelm));
bin->mNonFullRuns.Insert(runcur_mapelm);
}
bin->mCurrentRun = run;
} else {
size_t run_pageind =
(uintptr_t(run) - uintptr_t(aChunk)) >> gPageSize2Pow;
arena_chunk_map_t* run_mapelm = &aChunk->map[run_pageind];
MOZ_DIAGNOSTIC_ASSERT(bin->mNonFullRuns.Search(run_mapelm) == nullptr);
bin->mNonFullRuns.Insert(run_mapelm);
}
}
mStats.allocated_small -= size;
}
void
arena_t::DallocLarge(arena_chunk_t* aChunk, void* aPtr)
{
MOZ_DIAGNOSTIC_ASSERT((uintptr_t(aPtr) & gPageSizeMask) == 0);
size_t pageind = (uintptr_t(aPtr) - uintptr_t(aChunk)) >> gPageSize2Pow;
size_t size = aChunk->map[pageind].bits & ~gPageSizeMask;
memset(aPtr, kAllocPoison, size);
mStats.allocated_large -= size;
DallocRun((arena_run_t*)aPtr, true);
}
static inline void
arena_dalloc(void* aPtr, size_t aOffset, arena_t* aArena)
{
MOZ_ASSERT(aPtr);
MOZ_ASSERT(aOffset != 0);
MOZ_ASSERT(GetChunkOffsetForPtr(aPtr) == aOffset);
auto chunk = (arena_chunk_t*)((uintptr_t)aPtr - aOffset);
auto arena = chunk->arena;
MOZ_ASSERT(arena);
MOZ_DIAGNOSTIC_ASSERT(arena->mMagic == ARENA_MAGIC);
MOZ_RELEASE_ASSERT(!aArena || arena == aArena);
MutexAutoLock lock(arena->mLock);
size_t pageind = aOffset >> gPageSize2Pow;
arena_chunk_map_t* mapelm = &chunk->map[pageind];
MOZ_RELEASE_ASSERT((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0, "Double-free?");
if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
// Small allocation.
arena->DallocSmall(chunk, aPtr, mapelm);
} else {
// Large allocation.
arena->DallocLarge(chunk, aPtr);
}
}
static inline void
idalloc(void* ptr, arena_t* aArena)
{
size_t offset;
MOZ_ASSERT(ptr);
offset = GetChunkOffsetForPtr(ptr);
if (offset != 0) {
arena_dalloc(ptr, offset, aArena);
} else {
huge_dalloc(ptr, aArena);
}
}
void
arena_t::RallocShrinkLarge(arena_chunk_t* aChunk,
void* aPtr,
size_t aSize,
size_t aOldSize)
{
MOZ_ASSERT(aSize < aOldSize);
// Shrink the run, and make trailing pages available for other
// allocations.
MutexAutoLock lock(mLock);
TrimRunTail(aChunk, (arena_run_t*)aPtr, aOldSize, aSize, true);
mStats.allocated_large -= aOldSize - aSize;
}
// Returns whether reallocation was successful.
bool
arena_t::RallocGrowLarge(arena_chunk_t* aChunk,
void* aPtr,
size_t aSize,
size_t aOldSize)
{
size_t pageind = (uintptr_t(aPtr) - uintptr_t(aChunk)) >> gPageSize2Pow;
size_t npages = aOldSize >> gPageSize2Pow;
MutexAutoLock lock(mLock);
MOZ_DIAGNOSTIC_ASSERT(aOldSize ==
(aChunk->map[pageind].bits & ~gPageSizeMask));
// Try to extend the run.
MOZ_ASSERT(aSize > aOldSize);
if (pageind + npages < gChunkNumPages &&
(aChunk->map[pageind + npages].bits & CHUNK_MAP_ALLOCATED) == 0 &&
(aChunk->map[pageind + npages].bits & ~gPageSizeMask) >=
aSize - aOldSize) {
// The next run is available and sufficiently large. Split the
// following run, then merge the first part with the existing
// allocation.
if (!SplitRun((arena_run_t*)(uintptr_t(aChunk) +
((pageind + npages) << gPageSize2Pow)),
aSize - aOldSize,
true,
false)) {
return false;
}
aChunk->map[pageind].bits = aSize | CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
aChunk->map[pageind + npages].bits = CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
mStats.allocated_large += aSize - aOldSize;
return true;
}
return false;
}
void*
arena_t::RallocSmallOrLarge(void* aPtr, size_t aSize, size_t aOldSize)
{
void* ret;
size_t copysize;
SizeClass sizeClass(aSize);
// Try to avoid moving the allocation.
if (aOldSize <= gMaxLargeClass && sizeClass.Size() == aOldSize) {
if (aSize < aOldSize) {
memset((void*)(uintptr_t(aPtr) + aSize), kAllocPoison, aOldSize - aSize);
}
return aPtr;
}
if (sizeClass.Type() == SizeClass::Large && aOldSize > gMaxBinClass &&
aOldSize <= gMaxLargeClass) {
arena_chunk_t* chunk = GetChunkForPtr(aPtr);
if (sizeClass.Size() < aOldSize) {
// Fill before shrinking in order to avoid a race.
memset((void*)((uintptr_t)aPtr + aSize), kAllocPoison, aOldSize - aSize);
RallocShrinkLarge(chunk, aPtr, sizeClass.Size(), aOldSize);
return aPtr;
}
if (RallocGrowLarge(chunk, aPtr, sizeClass.Size(), aOldSize)) {
ApplyZeroOrJunk((void*)((uintptr_t)aPtr + aOldSize), aSize - aOldSize);
return aPtr;
}
}
// If we get here, then aSize and aOldSize are different enough that we
// need to move the object. In that case, fall back to allocating new
// space and copying.
ret = Malloc(aSize, false);
if (!ret) {
return nullptr;
}
// Junk/zero-filling were already done by arena_t::Malloc().
copysize = (aSize < aOldSize) ? aSize : aOldSize;
#ifdef VM_COPY_MIN
if (copysize >= VM_COPY_MIN) {
pages_copy(ret, aPtr, copysize);
} else
#endif
{
memcpy(ret, aPtr, copysize);
}
idalloc(aPtr, this);
return ret;
}
void*
arena_t::Ralloc(void* aPtr, size_t aSize, size_t aOldSize)
{
MOZ_DIAGNOSTIC_ASSERT(mMagic == ARENA_MAGIC);
MOZ_ASSERT(aPtr);
MOZ_ASSERT(aSize != 0);
return (aSize <= gMaxLargeClass) ? RallocSmallOrLarge(aPtr, aSize, aOldSize)
: RallocHuge(aPtr, aSize, aOldSize);
}
arena_t::arena_t(arena_params_t* aParams)
{
unsigned i;
MOZ_RELEASE_ASSERT(mLock.Init());
memset(&mLink, 0, sizeof(mLink));
memset(&mStats, 0, sizeof(arena_stats_t));
// Initialize chunks.
mChunksDirty.Init();
#ifdef MALLOC_DOUBLE_PURGE
new (&mChunksMAdvised) DoublyLinkedList<arena_chunk_t>();
#endif
mSpare = nullptr;
mNumDirty = 0;
// The default maximum amount of dirty pages allowed on arenas is a fraction
// of opt_dirty_max.
mMaxDirty =
(aParams && aParams->mMaxDirty) ? aParams->mMaxDirty : (opt_dirty_max / 8);
mRunsAvail.Init();
// Initialize bins.
SizeClass sizeClass(1);
for (i = 0;; i++) {
arena_bin_t& bin = mBins[i];
bin.Init(sizeClass);
// SizeClass doesn't want sizes larger than gMaxSubPageClass for now.
if (sizeClass.Size() == gMaxSubPageClass) {
break;
}
sizeClass = sizeClass.Next();
}
MOZ_ASSERT(i ==
kNumTinyClasses + kNumQuantumClasses + gNumSubPageClasses - 1);
#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
mMagic = ARENA_MAGIC;
#endif
}
arena_t*
ArenaCollection::CreateArena(bool aIsPrivate, arena_params_t* aParams)
{
fallible_t fallible;
arena_t* ret = new (fallible) arena_t(aParams);
if (!ret) {
// Only reached if there is an OOM error.
// OOM here is quite inconvenient to propagate, since dealing with it
// would require a check for failure in the fast path. Instead, punt
// by using the first arena.
// In practice, this is an extremely unlikely failure.
_malloc_message(_getprogname(), ": (malloc) Error initializing arena\n");
return mDefaultArena;
}
MutexAutoLock lock(mLock);
// TODO: Use random Ids.
ret->mId = mLastArenaId++;
(aIsPrivate ? mPrivateArenas : mArenas).Insert(ret);
return ret;
}
// End arena.
// ***************************************************************************
// Begin general internal functions.
void*
arena_t::MallocHuge(size_t aSize, bool aZero)
{
return PallocHuge(aSize, kChunkSize, aZero);
}
void*
arena_t::PallocHuge(size_t aSize, size_t aAlignment, bool aZero)
{
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(aSize);
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, aAlignment, false, &zeroed);
if (!ret) {
base_node_dealloc(node);
return nullptr;
}
if (aZero) {
chunk_ensure_zero(ret, csize, zeroed);
}
// Insert node into huge.
node->mAddr = ret;
psize = PAGE_CEILING(aSize);
node->mSize = psize;
node->mArena = this;
{
MutexAutoLock lock(huge_mtx);
huge.Insert(node);
// 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->mSize =
// 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;
}
#ifdef MALLOC_DECOMMIT
if (csize - psize > 0) {
pages_decommit((void*)((uintptr_t)ret + psize), csize - psize);
}
#endif
if (!aZero) {
#ifdef MALLOC_DECOMMIT
ApplyZeroOrJunk(ret, psize);
#else
ApplyZeroOrJunk(ret, csize);
#endif
}
return ret;
}
void*
arena_t::RallocHuge(void* aPtr, size_t aSize, size_t aOldSize)
{
void* ret;
size_t copysize;
// Avoid moving the allocation if the size class would not change.
if (aOldSize > gMaxLargeClass &&
CHUNK_CEILING(aSize) == CHUNK_CEILING(aOldSize)) {
size_t psize = PAGE_CEILING(aSize);
if (aSize < aOldSize) {
memset((void*)((uintptr_t)aPtr + aSize), kAllocPoison, aOldSize - aSize);
}
#ifdef MALLOC_DECOMMIT
if (psize < aOldSize) {
extent_node_t key;
pages_decommit((void*)((uintptr_t)aPtr + psize), aOldSize - psize);
// Update recorded size.
MutexAutoLock lock(huge_mtx);
key.mAddr = const_cast<void*>(aPtr);
extent_node_t* node = huge.Search(&key);
MOZ_ASSERT(node);
MOZ_ASSERT(node->mSize == aOldSize);
MOZ_RELEASE_ASSERT(node->mArena == this);
huge_allocated -= aOldSize - psize;
// No need to change huge_mapped, because we didn't (un)map anything.
node->mSize = psize;
} else if (psize > aOldSize) {
if (!pages_commit((void*)((uintptr_t)aPtr + aOldSize),
psize - aOldSize)) {
return nullptr;
}
}
#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 > aOldSize) {
// Update recorded size.
extent_node_t key;
MutexAutoLock lock(huge_mtx);
key.mAddr = const_cast<void*>(aPtr);
extent_node_t* node = huge.Search(&key);
MOZ_ASSERT(node);
MOZ_ASSERT(node->mSize == aOldSize);
MOZ_RELEASE_ASSERT(node->mArena == this);
huge_allocated += psize - aOldSize;
// No need to change huge_mapped, because we didn't
// (un)map anything.
node->mSize = psize;
}
if (aSize > aOldSize) {
ApplyZeroOrJunk((void*)((uintptr_t)aPtr + aOldSize), aSize - aOldSize);
}
return aPtr;
}
// If we get here, then aSize and aOldSize are different enough that we
// need to use a different size class. In that case, fall back to
// allocating new space and copying.
ret = MallocHuge(aSize, false);
if (!ret) {
return nullptr;
}
copysize = (aSize < aOldSize) ? aSize : aOldSize;
#ifdef VM_COPY_MIN
if (copysize >= VM_COPY_MIN) {
pages_copy(ret, aPtr, copysize);
} else
#endif
{
memcpy(ret, aPtr, copysize);
}
idalloc(aPtr, this);
return ret;
}
static void
huge_dalloc(void* aPtr, arena_t* aArena)
{
extent_node_t* node;
{
extent_node_t key;
MutexAutoLock lock(huge_mtx);
// Extract from tree of huge allocations.
key.mAddr = aPtr;
node = huge.Search(&key);
MOZ_RELEASE_ASSERT(node, "Double-free?");
MOZ_ASSERT(node->mAddr == aPtr);
MOZ_RELEASE_ASSERT(!aArena || node->mArena == aArena);
huge.Remove(node);
huge_allocated -= node->mSize;
huge_mapped -= CHUNK_CEILING(node->mSize);
}
// Unmap chunk.
chunk_dealloc(node->mAddr, CHUNK_CEILING(node->mSize), HUGE_CHUNK);
base_node_dealloc(node);
}
static size_t
GetKernelPageSize()
{
static size_t kernel_page_size = ([]() {
#ifdef XP_WIN
SYSTEM_INFO info;
GetSystemInfo(&info);
return info.dwPageSize;
#else
long result = sysconf(_SC_PAGESIZE);
MOZ_ASSERT(result != -1);
return result;
#endif
})();
return kernel_page_size;
}
// Returns whether the allocator was successfully initialized.
static bool
malloc_init_hard()
{
unsigned i;
const char* opts;
long result;
AutoLock<StaticMutex> lock(gInitLock);
if (malloc_initialized) {
// Another thread initialized the allocator before this one
// acquired gInitLock.
return true;
}
if (!thread_arena.init()) {
return true;
}
// Get page size and number of CPUs
result = GetKernelPageSize();
// We assume that the page size is a power of 2.
MOZ_ASSERT(((result - 1) & result) == 0);
#ifdef MALLOC_STATIC_PAGESIZE
if (gPageSize % (size_t)result) {
_malloc_message(
_getprogname(),
"Compile-time page size does not divide the runtime one.\n");
MOZ_CRASH();
}
#else
gPageSize = (size_t)result;
DefineGlobals();
#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
#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");
}
}
}
}
}
gRecycledSize = 0;
// Initialize chunks data.
chunks_mtx.Init();
gChunksBySize.Init();
gChunksByAddress.Init();
// Initialize huge allocation data.
huge_mtx.Init();
huge.Init();
huge_allocated = 0;
huge_mapped = 0;
// Initialize base allocation data structures.
base_mapped = 0;
base_committed = 0;
base_nodes = nullptr;
base_mtx.Init();
// Initialize arenas collection here.
if (!gArenas.Init()) {
return false;
}
// Assign the default arena to the initial thread.
thread_arena.set(gArenas.GetDefault());
if (!gChunkRTree.Init()) {
return false;
}
malloc_initialized = true;
// Dummy call so that the function is not removed by dead-code elimination
Debug::jemalloc_ptr_info(nullptr);
#if !defined(XP_WIN) && !defined(XP_DARWIN)
// Prevent potential deadlock on malloc locks after fork.
pthread_atfork(
_malloc_prefork, _malloc_postfork_parent, _malloc_postfork_child);
#endif
return true;
}
// End general internal functions.
// ***************************************************************************
// Begin malloc(3)-compatible functions.
// The BaseAllocator class is a helper class that implements the base allocator
// functions (malloc, calloc, realloc, free, memalign) for a given arena,
// or an appropriately chosen arena (per choose_arena()) when none is given.
struct BaseAllocator
{
#define MALLOC_DECL(name, return_type, ...) \
inline return_type name(__VA_ARGS__);
#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC_BASE
#include "malloc_decls.h"
explicit BaseAllocator(arena_t* aArena)
: mArena(aArena)
{
}
private:
arena_t* mArena;
};
#define MALLOC_DECL(name, return_type, ...) \
template<> \
inline return_type MozJemalloc::name(ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) \
{ \
BaseAllocator allocator(nullptr); \
return allocator.name(ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
}
#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC_BASE
#include "malloc_decls.h"
inline void*
BaseAllocator::malloc(size_t aSize)
{
void* ret;
arena_t* arena;
if (!malloc_init()) {
ret = nullptr;
goto RETURN;
}
if (aSize == 0) {
aSize = 1;
}
arena = mArena ? mArena : choose_arena(aSize);
ret = arena->Malloc(aSize, /* zero = */ false);
RETURN:
if (!ret) {
errno = ENOMEM;
}
return ret;
}
inline void*
BaseAllocator::memalign(size_t aAlignment, size_t aSize)
{
MOZ_ASSERT(((aAlignment - 1) & aAlignment) == 0);
if (!malloc_init()) {
return nullptr;
}
if (aSize == 0) {
aSize = 1;
}
aAlignment = aAlignment < sizeof(void*) ? sizeof(void*) : aAlignment;
arena_t* arena = mArena ? mArena : choose_arena(aSize);
return arena->Palloc(aAlignment, aSize);
}
inline void*
BaseAllocator::calloc(size_t aNum, size_t aSize)
{
void* ret;
if (malloc_init()) {
CheckedInt<size_t> checkedSize = CheckedInt<size_t>(aNum) * aSize;
if (checkedSize.isValid()) {
size_t allocSize = checkedSize.value();
if (allocSize == 0) {
allocSize = 1;
}
arena_t* arena = mArena ? mArena : choose_arena(allocSize);
ret = arena->Malloc(allocSize, /* zero = */ true);
} else {
ret = nullptr;
}
} else {
ret = nullptr;
}
if (!ret) {
errno = ENOMEM;
}
return ret;
}
inline void*
BaseAllocator::realloc(void* aPtr, size_t aSize)
{
void* ret;
if (aSize == 0) {
aSize = 1;
}
if (aPtr) {
MOZ_RELEASE_ASSERT(malloc_initialized);
auto info = AllocInfo::Get(aPtr);
auto arena = info.Arena();
MOZ_RELEASE_ASSERT(!mArena || arena == mArena);
ret = arena->Ralloc(aPtr, aSize, info.Size());
if (!ret) {
errno = ENOMEM;
}
} else {
if (!malloc_init()) {
ret = nullptr;
} else {
arena_t* arena = mArena ? mArena : choose_arena(aSize);
ret = arena->Malloc(aSize, /* zero = */ false);
}
if (!ret) {
errno = ENOMEM;
}
}
return ret;
}
inline void
BaseAllocator::free(void* aPtr)
{
size_t offset;
// A version of idalloc that checks for nullptr pointer.
offset = GetChunkOffsetForPtr(aPtr);
if (offset != 0) {
MOZ_RELEASE_ASSERT(malloc_initialized);
arena_dalloc(aPtr, offset, mArena);
} else if (aPtr) {
MOZ_RELEASE_ASSERT(malloc_initialized);
huge_dalloc(aPtr, mArena);
}
}
template<void* (*memalign)(size_t, size_t)>
struct AlignedAllocator
{
static inline int posix_memalign(void** aMemPtr,
size_t aAlignment,
size_t aSize)
{
void* result;
// alignment must be a power of two and a multiple of sizeof(void*)
if (((aAlignment - 1) & aAlignment) != 0 || aAlignment < sizeof(void*)) {
return EINVAL;
}
// The 0-->1 size promotion is done in the memalign() call below
result = memalign(aAlignment, aSize);
if (!result) {
return ENOMEM;
}
*aMemPtr = result;
return 0;
}
static inline void* aligned_alloc(size_t aAlignment, size_t aSize)
{
if (aSize % aAlignment) {
return nullptr;
}
return memalign(aAlignment, aSize);
}
static inline void* valloc(size_t aSize)
{
return memalign(GetKernelPageSize(), aSize);
}
};
template<>
inline int
MozJemalloc::posix_memalign(void** aMemPtr, size_t aAlignment, size_t aSize)
{
return AlignedAllocator<memalign>::posix_memalign(aMemPtr, aAlignment, aSize);
}
template<>
inline void*
MozJemalloc::aligned_alloc(size_t aAlignment, size_t aSize)
{
return AlignedAllocator<memalign>::aligned_alloc(aAlignment, aSize);
}
template<>
inline void*
MozJemalloc::valloc(size_t aSize)
{
return AlignedAllocator<memalign>::valloc(aSize);
}
// End malloc(3)-compatible functions.
// ***************************************************************************
// Begin non-standard functions.
// This was added by Mozilla for use by SQLite.
template<>
inline size_t
MozJemalloc::malloc_good_size(size_t aSize)
{
if (aSize <= gMaxLargeClass) {
// Small or large
aSize = SizeClass(aSize).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).
aSize = PAGE_CEILING(aSize);
}
return aSize;
}
template<>
inline size_t
MozJemalloc::malloc_usable_size(usable_ptr_t aPtr)
{
return AllocInfo::GetValidated(aPtr).Size();
}
template<>
inline void
MozJemalloc::jemalloc_stats(jemalloc_stats_t* aStats)
{
size_t non_arena_mapped, chunk_header_size;
if (!aStats) {
return;
}
if (!malloc_init()) {
memset(aStats, 0, sizeof(*aStats));
return;
}
// Gather runtime settings.
aStats->opt_junk = opt_junk;
aStats->opt_zero = opt_zero;
aStats->quantum = kQuantum;
aStats->small_max = kMaxQuantumClass;
aStats->large_max = gMaxLargeClass;
aStats->chunksize = kChunkSize;
aStats->page_size = gPageSize;
aStats->dirty_max = opt_dirty_max;
// Gather current memory usage statistics.
aStats->narenas = 0;
aStats->mapped = 0;
aStats->allocated = 0;
aStats->waste = 0;
aStats->page_cache = 0;
aStats->bookkeeping = 0;
aStats->bin_unused = 0;
non_arena_mapped = 0;
// Get huge mapped/allocated.
{
MutexAutoLock lock(huge_mtx);
non_arena_mapped += huge_mapped;
aStats->allocated += huge_allocated;
MOZ_ASSERT(huge_mapped >= huge_allocated);
}
// Get base mapped/allocated.
{
MutexAutoLock lock(base_mtx);
non_arena_mapped += base_mapped;
aStats->bookkeeping += base_committed;
MOZ_ASSERT(base_mapped >= base_committed);
}
gArenas.mLock.Lock();
// Iterate over arenas.
for (auto arena : gArenas.iter()) {
size_t arena_mapped, arena_allocated, arena_committed, arena_dirty, j,
arena_unused, arena_headers;
arena_run_t* run;
arena_headers = 0;
arena_unused = 0;
{
MutexAutoLock lock(arena->mLock);
arena_mapped = arena->mStats.mapped;
// "committed" counts dirty and allocated memory.
arena_committed = arena->mStats.committed << gPageSize2Pow;
arena_allocated =
arena->mStats.allocated_small + arena->mStats.allocated_large;
arena_dirty = arena->mNumDirty << gPageSize2Pow;
for (j = 0; j < kNumTinyClasses + kNumQuantumClasses + gNumSubPageClasses;
j++) {
arena_bin_t* bin = &arena->mBins[j];
size_t bin_unused = 0;
for (auto mapelm : bin->mNonFullRuns.iter()) {
run = (arena_run_t*)(mapelm->bits & ~gPageSizeMask);
bin_unused += run->mNumFree * bin->mSizeClass;
}
if (bin->mCurrentRun) {
bin_unused += bin->mCurrentRun->mNumFree * bin->mSizeClass;
}
arena_unused += bin_unused;
arena_headers += bin->mNumRuns * bin->mRunFirstRegionOffset;
}
}
MOZ_ASSERT(arena_mapped >= arena_committed);
MOZ_ASSERT(arena_committed >= arena_allocated + arena_dirty);
// "waste" is committed memory that is neither dirty nor
// allocated.
aStats->mapped += arena_mapped;
aStats->allocated += arena_allocated;
aStats->page_cache += arena_dirty;
aStats->waste += arena_committed - arena_allocated - arena_dirty -
arena_unused - arena_headers;
aStats->bin_unused += arena_unused;
aStats->bookkeeping += arena_headers;
aStats->narenas++;
}
gArenas.mLock.Unlock();
// Account for arena chunk headers in bookkeeping rather than waste.
chunk_header_size =
((aStats->mapped / aStats->chunksize) * gChunkHeaderNumPages)
<< gPageSize2Pow;
aStats->mapped += non_arena_mapped;
aStats->bookkeeping += chunk_header_size;
aStats->waste -= chunk_header_size;
MOZ_ASSERT(aStats->mapped >= aStats->allocated + aStats->waste +
aStats->page_cache + aStats->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* aChunk)
{
// See similar logic in arena_t::Purge().
for (size_t i = gChunkHeaderNumPages; i < gChunkNumPages; i++) {
// Find all adjacent pages with CHUNK_MAP_MADVISED set.
size_t npages;
for (npages = 0; aChunk->map[i + npages].bits & CHUNK_MAP_MADVISED &&
i + npages < gChunkNumPages;
npages++) {
// Turn off the chunk's MADV_FREED bit and turn on its
// DECOMMITTED bit.
MOZ_DIAGNOSTIC_ASSERT(
!(aChunk->map[i + npages].bits & CHUNK_MAP_DECOMMITTED));
aChunk->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*)aChunk) + (i << gPageSize2Pow),
npages << gPageSize2Pow);
Unused << pages_commit(((char*)aChunk) + (i << gPageSize2Pow),
npages << gPageSize2Pow);
}
i += npages;
}
}
// Explicitly remove all of this arena's MADV_FREE'd pages from memory.
void
arena_t::HardPurge()
{
MutexAutoLock lock(mLock);
while (!mChunksMAdvised.isEmpty()) {
arena_chunk_t* chunk = mChunksMAdvised.popFront();
hard_purge_chunk(chunk);
}
}
template<>
inline void
MozJemalloc::jemalloc_purge_freed_pages()
{
if (malloc_initialized) {
MutexAutoLock lock(gArenas.mLock);
for (auto arena : gArenas.iter()) {
arena->HardPurge();
}
}
}
#else // !defined MALLOC_DOUBLE_PURGE
template<>
inline void
MozJemalloc::jemalloc_purge_freed_pages()
{
// Do nothing.
}
#endif // defined MALLOC_DOUBLE_PURGE
template<>
inline void
MozJemalloc::jemalloc_free_dirty_pages(void)
{
if (malloc_initialized) {
MutexAutoLock lock(gArenas.mLock);
for (auto arena : gArenas.iter()) {
MutexAutoLock arena_lock(arena->mLock);
arena->Purge(true);
}
}
}
inline arena_t*
ArenaCollection::GetById(arena_id_t aArenaId, bool aIsPrivate)
{
if (!malloc_initialized) {
return nullptr;
}
// Use AlignedStorage2 to avoid running the arena_t constructor, while
// we only need it as a placeholder for mId.
mozilla::AlignedStorage2<arena_t> key;
key.addr()->mId = aArenaId;
MutexAutoLock lock(mLock);
arena_t* result = (aIsPrivate ? mPrivateArenas : mArenas).Search(key.addr());
MOZ_RELEASE_ASSERT(result);
return result;
}
#ifdef NIGHTLY_BUILD
template<>
inline arena_id_t
MozJemalloc::moz_create_arena_with_params(arena_params_t* aParams)
{
if (malloc_init()) {
arena_t* arena = gArenas.CreateArena(/* IsPrivate = */ true, aParams);
return arena->mId;
}
return 0;
}
template<>
inline void
MozJemalloc::moz_dispose_arena(arena_id_t aArenaId)
{
arena_t* arena = gArenas.GetById(aArenaId, /* IsPrivate = */ true);
MOZ_RELEASE_ASSERT(arena);
gArenas.DisposeArena(arena);
}
#define MALLOC_DECL(name, return_type, ...) \
template<> \
inline return_type MozJemalloc::moz_arena_##name( \
arena_id_t aArenaId, ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) \
{ \
BaseAllocator allocator( \
gArenas.GetById(aArenaId, /* IsPrivate = */ true)); \
return allocator.name(ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
}
#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC_BASE
#include "malloc_decls.h"
#else
#define MALLOC_DECL(name, return_type, ...) \
template<> \
inline return_type MozJemalloc::name(ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) \
{ \
return DummyArenaAllocator<MozJemalloc>::name( \
ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
}
#define MALLOC_FUNCS MALLOC_FUNCS_ARENA
#include "malloc_decls.h"
#endif
// End non-standard functions.
// ***************************************************************************
// Begin library-private functions, used by threading libraries for protection
// of malloc during fork(). These functions are only called if the program is
// running in threaded mode, so there is no need to check whether the program
// is threaded here.
#ifndef XP_DARWIN
static
#endif
void
_malloc_prefork(void)
{
// Acquire all mutexes in a safe order.
gArenas.mLock.Lock();
for (auto arena : gArenas.iter()) {
arena->mLock.Lock();
}
base_mtx.Lock();
huge_mtx.Lock();
}
#ifndef XP_DARWIN
static
#endif
void
_malloc_postfork_parent(void)
{
// Release all mutexes, now that fork() has completed.
huge_mtx.Unlock();
base_mtx.Unlock();
for (auto arena : gArenas.iter()) {
arena->mLock.Unlock();
}
gArenas.mLock.Unlock();
}
#ifndef XP_DARWIN
static
#endif
void
_malloc_postfork_child(void)
{
// Reinitialize all mutexes, now that fork() has completed.
huge_mtx.Init();
base_mtx.Init();
for (auto arena : gArenas.iter()) {
arena->mLock.Init();
}
gArenas.mLock.Init();
}
// End library-private functions.
// ***************************************************************************
#ifdef MOZ_REPLACE_MALLOC
// Windows doesn't come with weak imports as they are possible with
// LD_PRELOAD or DYLD_INSERT_LIBRARIES on Linux/OSX. On this platform,
// the replacement functions are defined as variable pointers to the
// function resolved with GetProcAddress() instead of weak definitions
// of functions. On Android, the same needs to happen as well, because
// the Android linker doesn't handle weak linking with non LD_PRELOADed
// libraries, but LD_PRELOADing is not very convenient on Android, with
// the zygote.
#ifdef XP_DARWIN
#define MOZ_REPLACE_WEAK __attribute__((weak_import))
#elif defined(XP_WIN) || defined(ANDROID)
#define MOZ_DYNAMIC_REPLACE_INIT
#define replace_init replace_init_decl
#elif defined(__GNUC__)
#define MOZ_REPLACE_WEAK __attribute__((weak))
#endif
#include "replace_malloc.h"
#define MALLOC_DECL(name, return_type, ...) MozJemalloc::name,
static malloc_table_t gReplaceMallocTable = {
#include "malloc_decls.h"
};
#ifdef MOZ_DYNAMIC_REPLACE_INIT
#undef replace_init
typedef decltype(replace_init_decl) replace_init_impl_t;
static replace_init_impl_t* replace_init = nullptr;
#endif
#ifdef XP_WIN
typedef HMODULE replace_malloc_handle_t;
static replace_malloc_handle_t
replace_malloc_handle()
{
char replace_malloc_lib[1024];
if (GetEnvironmentVariableA("MOZ_REPLACE_MALLOC_LIB",
replace_malloc_lib,
sizeof(replace_malloc_lib)) > 0) {
return LoadLibraryA(replace_malloc_lib);
}
return nullptr;
}
#define REPLACE_MALLOC_GET_INIT_FUNC(handle) \
(replace_init_impl_t*)GetProcAddress(handle, "replace_init")
#elif defined(ANDROID)
#include <dlfcn.h>
typedef void* replace_malloc_handle_t;
static replace_malloc_handle_t
replace_malloc_handle()
{
const char* replace_malloc_lib = getenv("MOZ_REPLACE_MALLOC_LIB");
if (replace_malloc_lib && *replace_malloc_lib) {
return dlopen(replace_malloc_lib, RTLD_LAZY);
}
return nullptr;
}
#define REPLACE_MALLOC_GET_INIT_FUNC(handle) \
(replace_init_impl_t*)dlsym(handle, "replace_init")
#endif
static void
replace_malloc_init_funcs();
#ifdef MOZ_REPLACE_MALLOC_STATIC
extern "C" void
logalloc_init(malloc_table_t*, ReplaceMallocBridge**);
extern "C" void
dmd_init(malloc_table_t*, ReplaceMallocBridge**);
#endif
bool
Equals(malloc_table_t& aTable1, malloc_table_t& aTable2)
{
return memcmp(&aTable1, &aTable2, sizeof(malloc_table_t)) == 0;
}
// Below is the malloc implementation overriding jemalloc and calling the
// replacement functions if they exist.
static bool gReplaceMallocInitialized = false;
static ReplaceMallocBridge* gReplaceMallocBridge = nullptr;
static void
init()
{
#ifdef MOZ_REPLACE_MALLOC_STATIC
malloc_table_t initialTable = gReplaceMallocTable;
#endif
#ifdef MOZ_DYNAMIC_REPLACE_INIT
replace_malloc_handle_t handle = replace_malloc_handle();
if (handle) {
replace_init = REPLACE_MALLOC_GET_INIT_FUNC(handle);
}
#endif
// Set this *before* calling replace_init, otherwise if replace_init calls
// malloc() we'll get an infinite loop.
gReplaceMallocInitialized = true;
if (replace_init) {
replace_init(&gReplaceMallocTable, &gReplaceMallocBridge);
}
#ifdef MOZ_REPLACE_MALLOC_STATIC
if (Equals(initialTable, gReplaceMallocTable)) {
logalloc_init(&gReplaceMallocTable, &gReplaceMallocBridge);
}
#ifdef MOZ_DMD
if (Equals(initialTable, gReplaceMallocTable)) {
dmd_init(&gReplaceMallocTable, &gReplaceMallocBridge);
}
#endif
#endif
replace_malloc_init_funcs();
}
#define MALLOC_DECL(name, return_type, ...) \
template<> \
inline return_type ReplaceMalloc::name( \
ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) \
{ \
if (MOZ_UNLIKELY(!gReplaceMallocInitialized)) { \
init(); \
} \
return gReplaceMallocTable.name(ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
}
#include "malloc_decls.h"
MOZ_JEMALLOC_API struct ReplaceMallocBridge*
get_bridge(void)
{
if (MOZ_UNLIKELY(!gReplaceMallocInitialized)) {
init();
}
return gReplaceMallocBridge;
}
// posix_memalign, aligned_alloc, memalign and valloc all implement some kind
// of aligned memory allocation. For convenience, a replace-malloc library can
// skip defining replace_posix_memalign, replace_aligned_alloc and
// replace_valloc, and default implementations will be automatically derived
// from replace_memalign.
static void
replace_malloc_init_funcs()
{
if (gReplaceMallocTable.posix_memalign == MozJemalloc::posix_memalign &&
gReplaceMallocTable.memalign != MozJemalloc::memalign) {
gReplaceMallocTable.posix_memalign =
AlignedAllocator<ReplaceMalloc::memalign>::posix_memalign;
}
if (gReplaceMallocTable.aligned_alloc == MozJemalloc::aligned_alloc &&
gReplaceMallocTable.memalign != MozJemalloc::memalign) {
gReplaceMallocTable.aligned_alloc =
AlignedAllocator<ReplaceMalloc::memalign>::aligned_alloc;
}
if (gReplaceMallocTable.valloc == MozJemalloc::valloc &&
gReplaceMallocTable.memalign != MozJemalloc::memalign) {
gReplaceMallocTable.valloc =
AlignedAllocator<ReplaceMalloc::memalign>::valloc;
}
if (gReplaceMallocTable.moz_create_arena_with_params ==
MozJemalloc::moz_create_arena_with_params &&
gReplaceMallocTable.malloc != MozJemalloc::malloc) {
#define MALLOC_DECL(name, ...) \
gReplaceMallocTable.name = DummyArenaAllocator<ReplaceMalloc>::name;
#define MALLOC_FUNCS MALLOC_FUNCS_ARENA
#include "malloc_decls.h"
}
}
#endif // MOZ_REPLACE_MALLOC
// ***************************************************************************
// Definition of all the _impl functions
#define GENERIC_MALLOC_DECL2(name, name_impl, return_type, ...) \
return_type name_impl(ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) \
{ \
return DefaultMalloc::name(ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
}
#define GENERIC_MALLOC_DECL(name, return_type, ...) \
GENERIC_MALLOC_DECL2(name, name##_impl, return_type, ##__VA_ARGS__)
#define MALLOC_DECL(...) \
MOZ_MEMORY_API MACRO_CALL(GENERIC_MALLOC_DECL, (__VA_ARGS__))
#define MALLOC_FUNCS MALLOC_FUNCS_MALLOC
#include "malloc_decls.h"
#undef GENERIC_MALLOC_DECL
#define GENERIC_MALLOC_DECL(name, return_type, ...) \
GENERIC_MALLOC_DECL2(name, name, return_type, ##__VA_ARGS__)
#define MALLOC_DECL(...) \
MOZ_JEMALLOC_API MACRO_CALL(GENERIC_MALLOC_DECL, (__VA_ARGS__))
#define MALLOC_FUNCS (MALLOC_FUNCS_JEMALLOC | MALLOC_FUNCS_ARENA)
#include "malloc_decls.h"
// ***************************************************************************
#ifdef HAVE_DLOPEN
#include <dlfcn.h>
#endif
#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*) = free_impl;
MOZ_EXPORT void* (*__malloc_hook)(size_t) = malloc_impl;
MOZ_EXPORT void* (*__realloc_hook)(void*, size_t) = realloc_impl;
MOZ_EXPORT void* (*__memalign_hook)(size_t, size_t) = memalign_impl;
}
#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
#ifdef XP_WIN
void*
_recalloc(void* aPtr, size_t aCount, size_t aSize)
{
size_t oldsize = aPtr ? AllocInfo::Get(aPtr).Size() : 0;
CheckedInt<size_t> checkedSize = CheckedInt<size_t>(aCount) * aSize;
if (!checkedSize.isValid()) {
return nullptr;
}
size_t newsize = checkedSize.value();
// 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.
aPtr = DefaultMalloc::realloc(aPtr, newsize);
if (aPtr && oldsize < newsize) {
memset((void*)((uintptr_t)aPtr + oldsize), 0, newsize - oldsize);
}
return aPtr;
}
// 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* aPtr, size_t newsize)
{
if (AllocInfo::Get(aPtr).Size() >= newsize) {
return aPtr;
}
return nullptr;
}
size_t
_msize(void* aPtr)
{
return DefaultMalloc::malloc_usable_size(aPtr);
}
#endif
View git blame Copy permalink