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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /memory/build/mozjemalloc.cpp
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'memory/build/mozjemalloc.cpp')
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+/* -*- 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, the size
+// classes in each category are as follows (for x86, x86_64 and Apple Silicon):
+//
+// |=========================================================|
+// | Category | Subcategory | x86 | x86_64 | Mac ARM |
+// |---------------------------+---------+---------+---------|
+// | Word size | 32 bit | 64 bit | 64 bit |
+// | Page size | 4 Kb | 4 Kb | 16 Kb |
+// |=========================================================|
+// | Small | Tiny | 4/-w | -w | - |
+// | | | 8 | 8/-w | 8 |
+// | |----------------+---------|---------|---------|
+// | | Quantum-spaced | 16 | 16 | 16 |
+// | | | 32 | 32 | 32 |
+// | | | 48 | 48 | 48 |
+// | | | ... | ... | ... |
+// | | | 480 | 480 | 480 |
+// | | | 496 | 496 | 496 |
+// | |----------------+---------|---------|---------|
+// | | Quantum-wide- | 512 | 512 | 512 |
+// | | spaced | 768 | 768 | 768 |
+// | | | ... | ... | ... |
+// | | | 3584 | 3584 | 3584 |
+// | | | 3840 | 3840 | 3840 |
+// | |----------------+---------|---------|---------|
+// | | Sub-page | - | - | 4096 |
+// | | | - | - | 8 kB |
+// |=========================================================|
+// | Large | 4 kB | 4 kB | - |
+// | | 8 kB | 8 kB | - |
+// | | 12 kB | 12 kB | - |
+// | | 16 kB | 16 kB | 16 kB |
+// | | ... | ... | - |
+// | | 32 kB | 32 kB | 32 kB |
+// | | ... | ... | ... |
+// | | 1008 kB | 1008 kB | 1008 kB |
+// | | 1012 kB | 1012 kB | - |
+// | | 1016 kB | 1016 kB | - |
+// | | 1020 kB | 1020 kB | - |
+// |=========================================================|
+// | Huge | 1 MB | 1 MB | 1 MB |
+// | | 2 MB | 2 MB | 2 MB |
+// | | 3 MB | 3 MB | 3 MB |
+// | | ... | ... | ... |
+// |=========================================================|
+//
+// Legend:
+// n: Size class exists for this platform.
+// n/-w: This size class doesn't exist on Windows (see kMinTinyClass).
+// -: This size class doesn't exist for this platform.
+// ...: Size classes follow a pattern here.
+//
+// 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>
+#include <optional>
+#include <type_traits>
+#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/ArrayUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/DoublyLinkedList.h"
+#include "mozilla/HelperMacros.h"
+#include "mozilla/Likely.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/RandomNum.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/XorShift128PlusRNG.h"
+#include "mozilla/fallible.h"
+#include "rb.h"
+#include "Mutex.h"
+#include "Utils.h"
+
+#if defined(XP_WIN)
+# include "mozmemory_utils.h"
+#endif
+
+// For GetGeckoProcessType(), when it's used.
+#if defined(XP_WIN) && !defined(JS_STANDALONE)
+# include "mozilla/ProcessType.h"
+#endif
+
+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
+
+// Define MALLOC_RUNTIME_CONFIG depending on MOZ_DEBUG. Overriding this as
+// a build option allows us to build mozjemalloc/firefox without runtime asserts
+// but with runtime configuration. Making some testing easier.
+
+#ifdef MOZ_DEBUG
+# define MALLOC_RUNTIME_CONFIG
+#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 MALLOC_RUNTIME_CONFIG
+# if !defined(__ia64__) && !defined(__sparc__) && !defined(__mips__) && \
+ !defined(__aarch64__) && !defined(__powerpc__) && !defined(XP_MACOSX) && \
+ !defined(__loongarch__)
+# 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
+// Newer Linux systems support MADV_FREE, but we're not supporting
+// that properly. bug #1406304.
+# if defined(XP_LINUX) && defined(MADV_FREE)
+# undef MADV_FREE
+# endif
+# 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;
+
+// Our size classes are inclusive ranges of memory sizes. By describing the
+// minimums and how memory is allocated in each range the maximums can be
+// calculated.
+
+// 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;
+
+// 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;
+static const size_t kMinQuantumWideClass = 512;
+static const size_t kMinSubPageClass = 4_KiB;
+
+// Amount (quantum) separating quantum-spaced size classes.
+static const size_t kQuantum = 16;
+static const size_t kQuantumMask = kQuantum - 1;
+static const size_t kQuantumWide = 256;
+static const size_t kQuantumWideMask = kQuantumWide - 1;
+
+static const size_t kMaxQuantumClass = kMinQuantumWideClass - kQuantum;
+static const size_t kMaxQuantumWideClass = kMinSubPageClass - kQuantumWide;
+
+// We can optimise some divisions to shifts if these are powers of two.
+static_assert(mozilla::IsPowerOfTwo(kQuantum),
+ "kQuantum is not a power of two");
+static_assert(mozilla::IsPowerOfTwo(kQuantumWide),
+ "kQuantumWide is not a power of two");
+
+static_assert(kMaxQuantumClass % kQuantum == 0,
+ "kMaxQuantumClass is not a multiple of kQuantum");
+static_assert(kMaxQuantumWideClass % kQuantumWide == 0,
+ "kMaxQuantumWideClass is not a multiple of kQuantumWide");
+static_assert(kQuantum < kQuantumWide,
+ "kQuantum must be smaller than kQuantumWide");
+static_assert(mozilla::IsPowerOfTwo(kMinSubPageClass),
+ "kMinSubPageClass is not a power of two");
+
+// Number of (2^n)-spaced tiny classes.
+static const size_t kNumTinyClasses =
+ LOG2(kMaxTinyClass) - LOG2(kMinTinyClass) + 1;
+
+// Number of quantum-spaced classes. We add kQuantum(Max) before subtracting to
+// avoid underflow when a class is empty (Max<Min).
+static const size_t kNumQuantumClasses =
+ (kMaxQuantumClass + kQuantum - kMinQuantumClass) / kQuantum;
+static const size_t kNumQuantumWideClasses =
+ (kMaxQuantumWideClass + kQuantumWide - kMinQuantumWideClass) / kQuantumWide;
+
+// 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(__powerpc64__)
+static const size_t gPageSize = 64_KiB;
+# elif defined(__loongarch64)
+static const size_t gPageSize = 16_KiB;
+# else
+static const size_t gPageSize = 4_KiB;
+# endif
+static const size_t gRealPageSize = gPageSize;
+
+#else
+// When MALLOC_OPTIONS contains one or several `P`s, the page size used
+// across the allocator is multiplied by 2 for each `P`, but we also keep
+// the real page size for code paths that need it. gPageSize is thus a
+// power of two greater or equal to gRealPageSize.
+static size_t gRealPageSize;
+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__))
+# define GLOBAL_CONSTEXPR constexpr
+#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
+# define GLOBAL_CONSTEXPR
+#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, or zero if there are none
+DEFINE_GLOBAL(size_t)
+gMaxSubPageClass = gPageSize / 2 >= kMinSubPageClass ? gPageSize / 2 : 0;
+
+// Max size class for bins.
+#define gMaxBinClass \
+ (gMaxSubPageClass ? gMaxSubPageClass : kMaxQuantumWideClass)
+
+// Number of sub-page bins.
+DEFINE_GLOBAL(uint8_t)
+gNumSubPageClasses = []() GLOBAL_CONSTEXPR -> uint8_t {
+ if GLOBAL_CONSTEXPR (gMaxSubPageClass != 0) {
+ return FloorLog2(gMaxSubPageClass) - LOG2(kMinSubPageClass) + 1;
+ }
+ return 0;
+}();
+
+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 plus a guard page.
+DEFINE_GLOBAL(size_t)
+gChunkHeaderNumPages =
+ 1 + (((sizeof(arena_chunk_t) +
+ sizeof(arena_chunk_map_t) * (gChunkNumPages - 1) + gPageSizeMask) &
+ ~gPageSizeMask) >>
+ gPageSize2Pow);
+
+// One chunk, minus the header, minus a guard page
+DEFINE_GLOBAL(size_t)
+gMaxLargeClass =
+ kChunkSize - gPageSize - (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 <= kQuantumWide);
+GLOBAL_ASSERT(!kNumQuantumWideClasses ||
+ kQuantumWide <= (kMinSubPageClass - kMaxQuantumClass));
+
+GLOBAL_ASSERT(kQuantumWide <= kMaxQuantumClass);
+
+GLOBAL_ASSERT(gMaxSubPageClass >= kMinSubPageClass || gMaxSubPageClass == 0);
+GLOBAL_ASSERT(gMaxLargeClass >= gMaxSubPageClass);
+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))
+#define QUANTUM_WIDE_CEILING(a) \
+ (((a) + (kQuantumWideMask)) & ~(kQuantumWideMask))
+
+// Return the smallest sub page-size that is >= a.
+#define SUBPAGE_CEILING(a) (RoundUpPow2(a))
+
+// Return the smallest pagesize multiple that is >= s.
+#define PAGE_CEILING(s) (((s) + gPageSizeMask) & ~gPageSizeMask)
+
+// Number of all the small-allocated classes
+#define NUM_SMALL_CLASSES \
+ (kNumTinyClasses + kNumQuantumClasses + kNumQuantumWideClasses + \
+ gNumSubPageClasses)
+
+// ***************************************************************************
+// 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.
+#if defined(_MSC_VER) && !defined(__clang__)
+// MSVC may create a static initializer for an Atomic<bool>, which may actually
+// run after `malloc_init` has been called once, which triggers multiple
+// initializations.
+// We work around the problem by not using an Atomic<bool> at all. There is a
+// theoretical problem with using `malloc_initialized` non-atomically, but
+// practically, this is only true if `malloc_init` is never called before
+// threads are created.
+static bool malloc_initialized;
+#else
+static Atomic<bool, SequentiallyConsistent> malloc_initialized;
+#endif
+
+static StaticMutex gInitLock MOZ_UNANNOTATED = {STATIC_MUTEX_INIT};
+
+// ***************************************************************************
+// 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 {
+ union {
+ // Linkage for the size/address-ordered tree for chunk recycling.
+ RedBlackTreeNode<extent_node_t> mLinkBySize;
+ // Arena id for huge allocations. It's meant to match mArena->mId,
+ // which only holds true when the arena hasn't been disposed of.
+ arena_id_t mArenaId;
+ };
+
+ // 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,
+ QuantumWide,
+ 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 <= kMaxQuantumWideClass) {
+ mType = QuantumWide;
+ mSize = QUANTUM_WIDE_CEILING(aSize);
+ } else if (aSize <= gMaxSubPageClass) {
+ mType = SubPage;
+ mSize = SUBPAGE_CEILING(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;
+};
+
+// Fast division
+//
+// During deallocation we want to divide by the size class. This class
+// provides a routine and sets up a constant as follows.
+//
+// To divide by a number D that is not a power of two we multiply by (2^17 /
+// D) and then right shift by 17 positions.
+//
+// X / D
+//
+// becomes
+//
+// (X * m) >> p
+//
+// Where m is calculated during the FastDivisor constructor similarly to:
+//
+// m = 2^p / D
+//
+template <typename T>
+class FastDivisor {
+ private:
+ // The shift amount (p) is chosen to minimise the size of m while
+ // working for divisors up to 65536 in steps of 16. I arrived at 17
+ // experimentally. I wanted a low number to minimise the range of m
+ // so it can fit in a uint16_t, 16 didn't work but 17 worked perfectly.
+ //
+ // We'd need to increase this if we allocated memory on smaller boundaries
+ // than 16.
+ static const unsigned p = 17;
+
+ // We can fit the inverted divisor in 16 bits, but we template it here for
+ // convenience.
+ T m;
+
+ public:
+ // Needed so mBins can be constructed.
+ FastDivisor() : m(0) {}
+
+ FastDivisor(unsigned div, unsigned max) {
+ MOZ_ASSERT(div <= max);
+
+ // divide_inv_shift is large enough.
+ MOZ_ASSERT((1U << p) >= div);
+
+ // The calculation here for m is formula 26 from Section
+ // 10-9 "Unsigned Division by Divisors >= 1" in
+ // Henry S. Warren, Jr.'s Hacker's Delight, 2nd Ed.
+ unsigned m_ = ((1U << p) + div - 1 - (((1U << p) - 1) % div)) / div;
+
+ // Make sure that max * m does not overflow.
+ MOZ_DIAGNOSTIC_ASSERT(max < UINT_MAX / m_);
+
+ MOZ_ASSERT(m_ <= std::numeric_limits<T>::max());
+ m = static_cast<T>(m_);
+
+ // Initialisation made m non-zero.
+ MOZ_ASSERT(m);
+
+ // Test that all the divisions in the range we expected would work.
+#ifdef MOZ_DEBUG
+ for (unsigned num = 0; num < max; num += div) {
+ MOZ_ASSERT(num / div == divide(num));
+ }
+#endif
+ }
+
+ // Note that this always occurs in uint32_t regardless of m's type. If m is
+ // a uint16_t it will be zero-extended before the multiplication. We also use
+ // uint32_t rather than something that could possibly be larger because it is
+ // most-likely the cheapest multiplication.
+ inline uint32_t divide(uint32_t num) const {
+ // Check that m was initialised.
+ MOZ_ASSERT(m);
+ return (num * m) >> p;
+ }
+};
+
+template <typename T>
+unsigned inline operator/(unsigned num, FastDivisor<T> divisor) {
+ return divisor.divide(num);
+}
+
+// ***************************************************************************
+// 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 MOZ_UNANNOTATED;
+ 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;
+ }
+};
+} // namespace mozilla
+#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 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.
+ uint32_t mNumRuns;
+
+ // A constant for fast division by size class. This value is 16 bits wide so
+ // it is placed last.
+ FastDivisor<uint16_t> mSizeDivisor;
+
+ // Total number of pages in a run for this bin's size class.
+ uint8_t mRunSizePages;
+
+ // 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 8 KiB 256 16 KiB 272 8 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 768 16 KiB 1024 64 KiB
+ // 1280 24 KiB 1536 32 KiB 1792 16 KiB 2048 128 KiB
+ // 2304 16 KiB 2560 48 KiB 2816 36 KiB 3072 64 KiB
+ // 3328 36 KiB 3584 32 KiB 3840 64 KiB
+ inline void Init(SizeClass aSizeClass);
+};
+
+// We try to keep the above structure aligned with common cache lines sizes,
+// often that's 64 bytes on x86 and ARM, we don't make assumptions for other
+// architectures.
+#if defined(__x86_64__) || defined(__aarch64__)
+// On 64bit platforms this structure is often 48 bytes
+// long, which means every other array element will be properly aligned.
+static_assert(sizeof(arena_bin_t) == 48);
+#elif defined(__x86__) || defined(__arm__)
+static_assert(sizeof(arena_bin_t) == 32);
+#endif
+
+struct arena_t {
+#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
+ uint32_t mMagic;
+# define ARENA_MAGIC 0x947d3d24
+#endif
+
+ // Linkage for the tree of arenas by id.
+ RedBlackTreeNode<arena_t> mLink;
+
+ // Arena id, that we keep away from the beginning of the struct so that
+ // free list pointers in TypedBaseAlloc<arena_t> don't overflow in it,
+ // and it keeps the value it had after the destructor.
+ arena_id_t mId;
+
+ // All operations on this arena require that lock be locked.
+ Mutex mLock MOZ_UNANNOTATED;
+
+ 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;
+
+ // A per-arena opt-in to randomize the offset of small allocations
+ bool mRandomizeSmallAllocations;
+
+ // Whether this is a private arena. Multiple public arenas are just a
+ // performance optimization and not a safety feature.
+ //
+ // Since, for example, we don't want thread-local arenas to grow too much, we
+ // use the default arena for bigger allocations. We use this member to allow
+ // realloc() to switch out of our arena if needed (which is not allowed for
+ // private arenas for security).
+ bool mIsPrivate;
+
+ // A pseudorandom number generator. Initially null, it gets initialized
+ // on first use to avoid recursive malloc initialization (e.g. on OSX
+ // arc4random allocates memory).
+ mozilla::non_crypto::XorShift128PlusRNG* mPRNG;
+
+ 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;
+
+ int32_t mMaxDirtyIncreaseOverride;
+ int32_t mMaxDirtyDecreaseOverride;
+
+ 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 | 768 |
+ // | 36 | 1024 |
+ // | : :
+ // | : :
+ // | 46 | 3584 |
+ // | 47 | 3840 |
+ // +----------+------+
+ arena_bin_t mBins[1]; // Dynamically sized.
+
+ explicit arena_t(arena_params_t* aParams, bool aIsPrivate);
+ ~arena_t();
+
+ private:
+ void InitChunk(arena_chunk_t* aChunk, bool aZeroed);
+
+ // This may return a chunk that should be destroyed with chunk_dealloc outside
+ // of the arena lock. It is not the same chunk as was passed in (since that
+ // chunk now becomes mSpare).
+ [[nodiscard]] arena_chunk_t* DeallocChunk(arena_chunk_t* aChunk);
+
+ arena_run_t* AllocRun(size_t aSize, bool aLarge, bool aZero);
+
+ arena_chunk_t* DallocRun(arena_run_t* aRun, bool aDirty);
+
+ [[nodiscard]] 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 uint8_t FindFreeBitInMask(uint32_t aMask, uint32_t& aRng);
+
+ inline void* ArenaRunRegAlloc(arena_run_t* aRun, 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);
+
+ // This may return a chunk that should be destroyed with chunk_dealloc outside
+ // of the arena lock. It is not the same chunk as was passed in (since that
+ // chunk now becomes mSpare).
+ [[nodiscard]] inline arena_chunk_t* DallocSmall(arena_chunk_t* aChunk,
+ void* aPtr,
+ arena_chunk_map_t* aMapElm);
+
+ [[nodiscard]] arena_chunk_t* DallocLarge(arena_chunk_t* aChunk, void* aPtr);
+
+ void* Ralloc(void* aPtr, size_t aSize, size_t aOldSize);
+
+ size_t EffectiveMaxDirty();
+
+ // Passing one means purging all.
+ void Purge(size_t aMaxDirty);
+
+ void HardPurge();
+
+ void* operator new(size_t aCount) = delete;
+
+ void* operator new(size_t aCount, const fallible_t&) noexcept;
+
+ void operator delete(void*);
+};
+
+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(/* aIsPrivate = */ 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);
+ MOZ_RELEASE_ASSERT(mPrivateArenas.Search(aArena),
+ "Can only dispose of private arenas");
+ mPrivateArenas.Remove(aArena);
+ delete aArena;
+ }
+
+ void SetDefaultMaxDirtyPageModifier(int32_t aModifier) {
+ mDefaultMaxDirtyPageModifier = aModifier;
+ }
+ int32_t DefaultMaxDirtyPageModifier() { return mDefaultMaxDirtyPageModifier; }
+
+ 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 MOZ_UNANNOTATED;
+
+ private:
+ inline arena_t* GetByIdInternal(arena_id_t aArenaId, bool aIsPrivate);
+
+ arena_t* mDefaultArena;
+ arena_id_t mLastPublicArenaId;
+ Tree mArenas;
+ Tree mPrivateArenas;
+ Atomic<int32_t> mDefaultMaxDirtyPageModifier;
+};
+
+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
+ MOZ_GUARDED_BY(chunks_mtx);
+static RedBlackTree<extent_node_t, ExtentTreeTrait> gChunksByAddress
+ MOZ_GUARDED_BY(chunks_mtx);
+
+// 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
+ MOZ_GUARDED_BY(huge_mtx);
+
+// Huge allocation statistics.
+static size_t huge_allocated MOZ_GUARDED_BY(huge_mtx);
+static size_t huge_mapped MOZ_GUARDED_BY(huge_mtx);
+
+// **************************
+// base (internal allocation).
+
+static Mutex base_mtx;
+
+// 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 MOZ_GUARDED_BY(base_mtx);
+static void* base_next_addr MOZ_GUARDED_BY(base_mtx);
+static void* base_next_decommitted MOZ_GUARDED_BY(base_mtx);
+// Address immediately past base_pages.
+static void* base_past_addr MOZ_GUARDED_BY(base_mtx);
+static size_t base_mapped MOZ_GUARDED_BY(base_mtx);
+static size_t base_committed MOZ_GUARDED_BY(base_mtx);
+
+// ******
+// 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.
+//
+// Junk - write "junk" to freshly allocated cells.
+// Poison - write "poison" to cells upon deallocation.
+
+const uint8_t kAllocJunk = 0xe4;
+const uint8_t kAllocPoison = 0xe5;
+
+#ifdef MALLOC_RUNTIME_CONFIG
+static bool opt_junk = true;
+static bool opt_poison = true;
+static bool opt_zero = false;
+#else
+static const bool opt_junk = false;
+static const bool opt_poison = true;
+static const bool opt_zero = false;
+#endif
+static bool opt_randomize_small = true;
+
+// ***************************************************************************
+// 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();
+
+#ifndef XP_WIN
+# 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);
+#endif
+
+// 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>"; }
+
+static inline void MaybePoison(void* aPtr, size_t aSize) {
+ if (opt_poison) {
+ memset(aPtr, kAllocPoison, aSize);
+ }
+}
+
+// Fill the given range of memory with zeroes or junk depending on opt_junk and
+// opt_zero.
+static inline void ApplyZeroOrJunk(void* aPtr, size_t aSize) {
+ if (opt_junk) {
+ memset(aPtr, kAllocJunk, aSize);
+ } else if (opt_zero) {
+ memset(aPtr, 0, aSize);
+ }
+}
+
+// On Windows, delay crashing on OOM.
+#ifdef XP_WIN
+
+// Implementation of VirtualAlloc wrapper (bug 1716727).
+namespace MozAllocRetries {
+
+// Maximum retry count on OOM.
+constexpr size_t kMaxAttempts = 10;
+// Minimum delay time between retries. (The actual delay time may be larger. See
+// Microsoft's documentation for ::Sleep() for details.)
+constexpr size_t kDelayMs = 50;
+
+using StallSpecs = ::mozilla::StallSpecs;
+
+static constexpr StallSpecs maxStall = {.maxAttempts = kMaxAttempts,
+ .delayMs = kDelayMs};
+
+static inline StallSpecs GetStallSpecs() {
+# if defined(JS_STANDALONE)
+ // GetGeckoProcessType() isn't available in this configuration. (SpiderMonkey
+ // on Windows mostly skips this in favor of directly calling ::VirtualAlloc(),
+ // though, so it's probably not going to matter whether we stall here or not.)
+ return maxStall;
+# else
+ switch (GetGeckoProcessType()) {
+ // For the main process, stall for the maximum permissible time period. (The
+ // main process is the most important one to keep alive.)
+ case GeckoProcessType::GeckoProcessType_Default:
+ return maxStall;
+
+ // For all other process types, stall for at most half as long.
+ default:
+ return {.maxAttempts = maxStall.maxAttempts / 2,
+ .delayMs = maxStall.delayMs};
+ }
+# endif
+}
+
+// Drop-in wrapper around VirtualAlloc. When out of memory, may attempt to stall
+// and retry rather than returning immediately, in hopes that the page file is
+// about to be expanded by Windows.
+//
+// Ref: https://docs.microsoft.com/en-us/troubleshoot/windows-client/performance/slow-page-file-growth-memory-allocation-errors
+[[nodiscard]] void* MozVirtualAlloc(LPVOID lpAddress, SIZE_T dwSize,
+ DWORD flAllocationType, DWORD flProtect) {
+ DWORD const lastError = ::GetLastError();
+
+ constexpr auto IsOOMError = [] {
+ switch (::GetLastError()) {
+ // This is the usual error result from VirtualAlloc for OOM.
+ case ERROR_COMMITMENT_LIMIT:
+ // Although rare, this has also been observed in low-memory situations.
+ // (Presumably this means Windows can't allocate enough kernel-side space
+ // for its own internal representation of the process's virtual address
+ // space.)
+ case ERROR_NOT_ENOUGH_MEMORY:
+ return true;
+ }
+ return false;
+ };
+
+ {
+ void* ptr = ::VirtualAlloc(lpAddress, dwSize, flAllocationType, flProtect);
+ if (MOZ_LIKELY(ptr)) return ptr;
+
+ // We can't do anything for errors other than OOM...
+ if (!IsOOMError()) return nullptr;
+ // ... or if this wasn't a request to commit memory in the first place.
+ // (This function has no strategy for resolving MEM_RESERVE failures.)
+ if (!(flAllocationType & MEM_COMMIT)) return nullptr;
+ }
+
+ // Retry as many times as desired (possibly zero).
+ const StallSpecs stallSpecs = GetStallSpecs();
+
+ const auto ret =
+ stallSpecs.StallAndRetry(&::Sleep, [&]() -> std::optional<void*> {
+ void* ptr =
+ ::VirtualAlloc(lpAddress, dwSize, flAllocationType, flProtect);
+
+ if (ptr) {
+ // The OOM status has been handled, and should not be reported to
+ // telemetry.
+ if (IsOOMError()) {
+ ::SetLastError(lastError);
+ }
+ return ptr;
+ }
+
+ // Failure for some reason other than OOM.
+ if (!IsOOMError()) {
+ return nullptr;
+ }
+
+ return std::nullopt;
+ });
+
+ return ret.value_or(nullptr);
+}
+} // namespace MozAllocRetries
+
+using MozAllocRetries::MozVirtualAlloc;
+
+namespace mozilla {
+MOZ_JEMALLOC_API StallSpecs GetAllocatorStallSpecs() {
+ return ::MozAllocRetries::GetStallSpecs();
+}
+} // namespace mozilla
+
+#endif // XP_WIN
+
+// ***************************************************************************
+
+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) {
+ // This will cause Access Violation on read and write and thus act as a
+ // guard page or region as well.
+ 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) {
+ // We'd like to report the OOM for our tooling, but we can't allocate
+ // memory at this point, so avoid the use of printf.
+ const char out_of_mappings[] =
+ "[unhandlable oom] Failed to mmap, likely no more mappings "
+ "available " __FILE__ " : " MOZ_STRINGIFY(__LINE__);
+ if (errno == ENOMEM) {
+# ifndef ANDROID
+ fputs(out_of_mappings, stderr);
+ fflush(stderr);
+# endif
+ MOZ_CRASH_ANNOTATE(out_of_mappings);
+ }
+ MOZ_REALLY_CRASH(__LINE__);
+ }
+ MozTagAnonymousMemory(aAddr, aSize, "jemalloc-decommitted");
+#endif
+}
+
+// Commit pages. Returns whether pages were committed.
+[[nodiscard]] 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 (!MozVirtualAlloc(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) MOZ_REQUIRES(base_mtx) {
+ 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 (pminsize < csize) {
+ pages_decommit(base_next_decommitted, csize - pminsize);
+ }
+ 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));
+
+ if (!pages_commit(
+ base_next_decommitted,
+ (uintptr_t)pbase_next_addr - (uintptr_t)base_next_decommitted)) {
+ return nullptr;
+ }
+
+ 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;
+}
+
+// A specialization of the base allocator with a free list.
+template <typename T>
+struct TypedBaseAlloc {
+ static T* sFirstFree;
+
+ static size_t size_of() { return sizeof(T); }
+
+ static T* alloc() {
+ T* ret;
+
+ base_mtx.Lock();
+ if (sFirstFree) {
+ ret = sFirstFree;
+ sFirstFree = *(T**)ret;
+ base_mtx.Unlock();
+ } else {
+ base_mtx.Unlock();
+ ret = (T*)base_alloc(size_of());
+ }
+
+ return ret;
+ }
+
+ static void dealloc(T* aNode) {
+ MutexAutoLock lock(base_mtx);
+ *(T**)aNode = sFirstFree;
+ sFirstFree = aNode;
+ }
+};
+
+using ExtentAlloc = TypedBaseAlloc<extent_node_t>;
+
+template <>
+extent_node_t* ExtentAlloc::sFirstFree = nullptr;
+
+template <>
+arena_t* TypedBaseAlloc<arena_t>::sFirstFree = nullptr;
+
+template <>
+size_t TypedBaseAlloc<arena_t>::size_of() {
+ // Allocate enough space for trailing bins.
+ return sizeof(arena_t) + (sizeof(arena_bin_t) * (NUM_SMALL_CLASSES - 1));
+}
+
+template <typename T>
+struct BaseAllocFreePolicy {
+ void operator()(T* aPtr) { TypedBaseAlloc<T>::dealloc(aPtr); }
+};
+
+using UniqueBaseNode =
+ UniquePtr<extent_node_t, BaseAllocFreePolicy<extent_node_t>>;
+
+// End Utility functions/macros.
+// ***************************************************************************
+// Begin chunk management functions.
+
+#ifdef XP_WIN
+
+static void* pages_map(void* aAddr, size_t aSize) {
+ void* ret = nullptr;
+ ret = MozVirtualAlloc(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 kChunkSize
+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);
+
+ kern_return_t r = vm_copy(mach_task_self(), (vm_address_t)src, (vm_size_t)n,
+ (vm_address_t)dest);
+ if (r != KERN_SUCCESS) {
+ MOZ_CRASH("vm_copy() failed");
+ }
+}
+
+#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, /* aCreate = */ 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 - gRealPageSize;
+ // 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) {
+ pages_decommit(addr, length);
+ return true;
+}
+
+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
+ // TypedBaseAlloc::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 = ExtentAlloc::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) {
+ ExtentAlloc::dealloc(node);
+ }
+ if (!pages_commit(ret, aSize)) {
+ return nullptr;
+ }
+ // pages_commit is guaranteed to zero the chunk.
+ if (aZeroed) {
+ *aZeroed = true;
+ }
+
+ 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 TypedBaseAlloc::alloc() may cause a new base chunk to
+ // be allocated, which could cause deadlock if chunks_mtx were already
+ // held.
+ UniqueBaseNode xnode(ExtentAlloc::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) {
+ // TypedBaseAlloc::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(/* aIsPrivate = */ false, /* aParams = */ 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;
+}
+
+inline uint8_t arena_t::FindFreeBitInMask(uint32_t aMask, uint32_t& aRng) {
+ if (mPRNG != nullptr) {
+ if (aRng == UINT_MAX) {
+ aRng = mPRNG->next() % 32;
+ }
+ uint8_t bitIndex;
+ // RotateRight asserts when provided bad input.
+ aMask = aRng ? RotateRight(aMask, aRng)
+ : aMask; // Rotate the mask a random number of slots
+ bitIndex = CountTrailingZeroes32(aMask);
+ return (bitIndex + aRng) % 32;
+ }
+ return CountTrailingZeroes32(aMask);
+}
+
+inline void* arena_t::ArenaRunRegAlloc(arena_run_t* aRun, arena_bin_t* aBin) {
+ void* ret;
+ unsigned i, mask, bit, regind;
+ uint32_t rndPos = UINT_MAX;
+
+ MOZ_DIAGNOSTIC_ASSERT(aRun->mMagic == ARENA_RUN_MAGIC);
+ MOZ_ASSERT(aRun->mRegionsMinElement < aBin->mRunNumRegionsMask);
+
+ // Move the first check outside the loop, so that aRun->mRegionsMinElement can
+ // be updated unconditionally, without the possibility of updating it
+ // multiple times.
+ i = aRun->mRegionsMinElement;
+ mask = aRun->mRegionsMask[i];
+ if (mask != 0) {
+ bit = FindFreeBitInMask(mask, rndPos);
+
+ regind = ((i << (LOG2(sizeof(int)) + 3)) + bit);
+ MOZ_ASSERT(regind < aBin->mRunNumRegions);
+ ret = (void*)(((uintptr_t)aRun) + aBin->mRunFirstRegionOffset +
+ (aBin->mSizeClass * regind));
+
+ // Clear bit.
+ mask ^= (1U << bit);
+ aRun->mRegionsMask[i] = mask;
+
+ return ret;
+ }
+
+ for (i++; i < aBin->mRunNumRegionsMask; i++) {
+ mask = aRun->mRegionsMask[i];
+ if (mask != 0) {
+ bit = FindFreeBitInMask(mask, rndPos);
+
+ regind = ((i << (LOG2(sizeof(int)) + 3)) + bit);
+ MOZ_ASSERT(regind < aBin->mRunNumRegions);
+ ret = (void*)(((uintptr_t)aRun) + aBin->mRunFirstRegionOffset +
+ (aBin->mSizeClass * regind));
+
+ // Clear bit.
+ mask ^= (1U << bit);
+ aRun->mRegionsMask[i] = mask;
+
+ // Make a note that nothing before this element
+ // contains a free region.
+ aRun->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) {
+ uint32_t diff, regind;
+ unsigned elm, bit;
+
+ MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
+
+ // Avoid doing division with a variable divisor if possible. Using
+ // actual division here can reduce allocator throughput by over 20%!
+ diff =
+ (uint32_t)((uintptr_t)ptr - (uintptr_t)run - bin->mRunFirstRegionOffset);
+
+ MOZ_ASSERT(diff <=
+ (static_cast<unsigned>(bin->mRunSizePages) << gPageSize2Pow));
+ regind = diff / bin->mSizeDivisor;
+
+ 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);
+}
+
+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.
+ arena_run_t* run = (arena_run_t*)(uintptr_t(aChunk) +
+ (gChunkHeaderNumPages << gPageSize2Pow));
+
+ // Clear the bits for the real header pages.
+ for (i = 0; i < gChunkHeaderNumPages - 1; i++) {
+ aChunk->map[i].bits = 0;
+ }
+ // Mark the leading guard page (last header page) as decommitted.
+ aChunk->map[i++].bits = CHUNK_MAP_DECOMMITTED;
+
+ // Mark the area usable for runs as available, note size at start and end
+ aChunk->map[i++].bits = gMaxLargeClass | flags;
+ for (; i < gChunkNumPages - 2; i++) {
+ aChunk->map[i].bits = flags;
+ }
+ aChunk->map[gChunkNumPages - 2].bits = gMaxLargeClass | flags;
+
+ // Mark the trailing guard page as decommitted.
+ aChunk->map[gChunkNumPages - 1].bits = CHUNK_MAP_DECOMMITTED;
+
+#ifdef MALLOC_DECOMMIT
+ // Start out decommitted, in order to force a closer correspondence
+ // between dirty pages and committed untouched pages. This includes
+ // leading and trailing guard pages.
+ pages_decommit((void*)(uintptr_t(run) - gPageSize),
+ gMaxLargeClass + 2 * gPageSize);
+#else
+ // Decommit the last header page (=leading page) as a guard.
+ pages_decommit((void*)(uintptr_t(run) - gPageSize), gPageSize);
+ // Decommit the last page as a guard.
+ pages_decommit((void*)(uintptr_t(aChunk) + kChunkSize - gPageSize),
+ gPageSize);
+#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
+}
+
+arena_chunk_t* 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
+
+ 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]);
+
+ arena_chunk_t* chunk_dealloc = mSpare;
+ mSpare = aChunk;
+ return chunk_dealloc;
+}
+
+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;
+}
+
+size_t arena_t::EffectiveMaxDirty() {
+ int32_t modifier = gArenas.DefaultMaxDirtyPageModifier();
+ if (modifier) {
+ int32_t arenaOverride =
+ modifier > 0 ? mMaxDirtyIncreaseOverride : mMaxDirtyDecreaseOverride;
+ if (arenaOverride) {
+ modifier = arenaOverride;
+ }
+ }
+
+ return modifier >= 0 ? mMaxDirty << modifier : mMaxDirty >> -modifier;
+}
+
+void arena_t::Purge(size_t aMaxDirty) {
+ arena_chunk_t* chunk;
+ size_t i, npages;
+
+#ifdef MOZ_DEBUG
+ size_t ndirty = 0;
+ for (auto chunk : mChunksDirty.iter()) {
+ ndirty += chunk->ndirty;
+ }
+ MOZ_ASSERT(ndirty == mNumDirty);
+#endif
+ MOZ_DIAGNOSTIC_ASSERT(aMaxDirty == 1 || (mNumDirty > aMaxDirty));
+
+ // 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 > (aMaxDirty >> 1)) {
+#ifdef MALLOC_DOUBLE_PURGE
+ bool madvised = false;
+#endif
+ chunk = mChunksDirty.Last();
+ MOZ_DIAGNOSTIC_ASSERT(chunk);
+ // Last page is DECOMMITTED as a guard page.
+ MOZ_ASSERT((chunk->map[gChunkNumPages - 1].bits & CHUNK_MAP_DECOMMITTED) !=
+ 0);
+ for (i = gChunkNumPages - 2; 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
+# ifdef XP_SOLARIS
+ posix_madvise((void*)(uintptr_t(chunk) + (i << gPageSize2Pow)),
+ (npages << gPageSize2Pow), MADV_FREE);
+# else
+ madvise((void*)(uintptr_t(chunk) + (i << gPageSize2Pow)),
+ (npages << gPageSize2Pow), MADV_FREE);
+# endif
+# ifdef MALLOC_DOUBLE_PURGE
+ madvised = true;
+# endif
+#endif
+ if (mNumDirty <= (aMaxDirty >> 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
+ }
+}
+
+arena_chunk_t* 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_RELEASE_ASSERT(run_ind < gChunkNumPages - 1);
+ if ((chunk->map[run_ind].bits & CHUNK_MAP_LARGE) != 0) {
+ size = chunk->map[run_ind].bits & ~gPageSizeMask;
+ run_pages = (size >> gPageSize2Pow);
+ } else {
+ run_pages = aRun->mBin->mRunSizePages;
+ size = run_pages << 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 - 1 &&
+ (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.
+ arena_chunk_t* chunk_dealloc = nullptr;
+ if ((chunk->map[gChunkHeaderNumPages].bits &
+ (~gPageSizeMask | CHUNK_MAP_ALLOCATED)) == gMaxLargeClass) {
+ chunk_dealloc = DeallocChunk(chunk);
+ }
+
+ size_t maxDirty = EffectiveMaxDirty();
+ if (mNumDirty > maxDirty) {
+ Purge(maxDirty);
+ }
+
+ return chunk_dealloc;
+}
+
+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;
+
+#ifdef MOZ_DEBUG
+ arena_chunk_t* no_chunk =
+#endif
+ DallocRun(aRun, false);
+ // This will never release a chunk as there's still at least one allocated
+ // run.
+ MOZ_ASSERT(!no_chunk);
+}
+
+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;
+
+#ifdef MOZ_DEBUG
+ arena_chunk_t* no_chunk =
+#endif
+ DallocRun((arena_run_t*)(uintptr_t(aRun) + aNewSize), aDirty);
+
+ // This will never release a chunk as there's still at least one allocated
+ // run.
+ MOZ_ASSERT(!no_chunk);
+}
+
+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(static_cast<size_t>(aBin->mRunSizePages) << gPageSize2Pow,
+ 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;
+
+ // Run size 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);
+
+ // 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;
+ }
+
+ // If next iteration is going to be larger than the largest possible large
+ // size class, then we didn't find a setup where the overhead is small
+ // enough, and we can't do better than the current settings, so just use
+ // that.
+ if (try_run_size + gPageSize > gMaxLargeClass) {
+ 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.
+ MOZ_ASSERT((try_run_size >> gPageSize2Pow) <= UINT8_MAX);
+ mRunSizePages = static_cast<uint8_t>(try_run_size >> gPageSize2Pow);
+ mRunNumRegions = try_nregs;
+ mRunNumRegionsMask = try_mask_nelms;
+ mRunFirstRegionOffset = try_reg0_offset;
+ mSizeDivisor = FastDivisor<uint16_t>(aSizeClass.Size(), try_run_size);
+}
+
+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:
+ // Although we divide 2 things by kQuantum, the compiler will
+ // reduce `kMinQuantumClass / kQuantum` and `kNumTinyClasses` to a
+ // single constant.
+ bin = &mBins[kNumTinyClasses + (aSize / kQuantum) -
+ (kMinQuantumClass / kQuantum)];
+ break;
+ case SizeClass::QuantumWide:
+ bin =
+ &mBins[kNumTinyClasses + kNumQuantumClasses + (aSize / kQuantumWide) -
+ (kMinQuantumWideClass / kQuantumWide)];
+ break;
+ case SizeClass::SubPage:
+ bin =
+ &mBins[kNumTinyClasses + kNumQuantumClasses + kNumQuantumWideClasses +
+ (FloorLog2(aSize) - LOG2(kMinSubPageClass))];
+ break;
+ default:
+ MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Unexpected size class type");
+ }
+ MOZ_DIAGNOSTIC_ASSERT(aSize == bin->mSizeClass);
+
+ {
+ // Before we lock, we determine if we need to randomize the allocation
+ // because if we do, we need to create the PRNG which might require
+ // allocating memory (arc4random on OSX for example) and we need to
+ // avoid the deadlock
+ if (MOZ_UNLIKELY(mRandomizeSmallAllocations && mPRNG == nullptr)) {
+ // This is frustrating. Because the code backing RandomUint64 (arc4random
+ // for example) may allocate memory, and because
+ // mRandomizeSmallAllocations is true and we haven't yet initilized mPRNG,
+ // we would re-enter this same case and cause a deadlock inside e.g.
+ // arc4random. So we temporarily disable mRandomizeSmallAllocations to
+ // skip this case and then re-enable it
+ mRandomizeSmallAllocations = false;
+ mozilla::Maybe<uint64_t> prngState1 = mozilla::RandomUint64();
+ mozilla::Maybe<uint64_t> prngState2 = mozilla::RandomUint64();
+ void* backing =
+ base_alloc(sizeof(mozilla::non_crypto::XorShift128PlusRNG));
+ mPRNG = new (backing) mozilla::non_crypto::XorShift128PlusRNG(
+ prngState1.valueOr(0), prngState2.valueOr(0));
+ mRandomizeSmallAllocations = true;
+ }
+ MOZ_ASSERT(!mRandomizeSmallAllocations || mPRNG);
+
+ 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 = ArenaRunRegAlloc(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;
+}
+
+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);
+ size_t pageind = (((uintptr_t)aPtr - (uintptr_t)chunk) >> gPageSize2Pow);
+ return GetInChunk(aPtr, chunk, pageind);
+ }
+
+ 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);
+ }
+
+ // Get the allocation information for a pointer we know is within a chunk
+ // (Small or large, not huge).
+ static inline AllocInfo GetInChunk(const void* aPtr, arena_chunk_t* aChunk,
+ size_t pageind) {
+ size_t mapbits = aChunk->map[pageind].bits;
+ MOZ_DIAGNOSTIC_ASSERT((mapbits & CHUNK_MAP_ALLOCATED) != 0);
+
+ size_t size;
+ if ((mapbits & CHUNK_MAP_LARGE) == 0) {
+ arena_run_t* run = (arena_run_t*)(mapbits & ~gPageSizeMask);
+ MOZ_DIAGNOSTIC_ASSERT(run->mMagic == ARENA_RUN_MAGIC);
+ size = run->mBin->mSizeClass;
+ } else {
+ size = mapbits & ~gPageSizeMask;
+ MOZ_DIAGNOSTIC_ASSERT(size != 0);
+ }
+
+ return AllocInfo(size, aChunk);
+ }
+
+ // 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() {
+ if (mSize <= gMaxLargeClass) {
+ return mChunk->arena;
+ }
+ // Best effort detection that we're not trying to access an already
+ // disposed arena. In the case of a disposed arena, the memory location
+ // pointed by mNode->mArena is either free (but still a valid memory
+ // region, per TypedBaseAlloc<arena_t>), in which case its id was reset,
+ // or has been reallocated for a new region, and its id is very likely
+ // different (per randomness). In both cases, the id is unlikely to
+ // match what it was for the disposed arena.
+ MOZ_RELEASE_ASSERT(mNode->mArenaId == mNode->mArena->mId);
+ return mNode->mArena;
+ }
+
+ bool IsValid() const { return !!mSize; }
+
+ 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, 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 = {TagLiveAlloc, node->mAddr, node->mSize, node->mArena->mId};
+ return;
+ }
+ }
+
+ // It's not a huge allocation. Check if we have a known chunk.
+ if (!gChunkRTree.Get(chunk)) {
+ *aInfo = {TagUnknown, nullptr, 0, 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, 0};
+ return;
+ }
+
+ size_t mapbits = chunk->map[pageind].bits;
+
+ if (!(mapbits & CHUNK_MAP_ALLOCATED)) {
+ void* pageaddr = (void*)(uintptr_t(aPtr) & ~gPageSizeMask);
+ *aInfo = {TagFreedPage, pageaddr, gPageSize, chunk->arena->mId};
+ 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, 0};
+ return;
+ }
+
+ mapbits = chunk->map[pageind].bits;
+ MOZ_DIAGNOSTIC_ASSERT(mapbits & CHUNK_MAP_LARGE);
+ if (!(mapbits & CHUNK_MAP_LARGE)) {
+ *aInfo = {TagUnknown, nullptr, 0, 0};
+ return;
+ }
+ }
+
+ void* addr = ((char*)chunk) + (pageind << gPageSize2Pow);
+ *aInfo = {TagLiveAlloc, addr, size, chunk->arena->mId};
+ 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, 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))) ? TagFreedAlloc : TagLiveAlloc;
+
+ *aInfo = {tag, addr, size, chunk->arena->mId};
+}
+
+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;
+}
+} // namespace Debug
+
+arena_chunk_t* 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);
+
+ arena_run_reg_dalloc(run, bin, aPtr, size);
+ run->mNumFree++;
+ arena_chunk_t* dealloc_chunk = nullptr;
+
+ 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
+ dealloc_chunk = 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;
+
+ return dealloc_chunk;
+}
+
+arena_chunk_t* 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;
+
+ mStats.allocated_large -= size;
+
+ return 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);
+
+ size_t pageind = aOffset >> gPageSize2Pow;
+ if (opt_poison) {
+ AllocInfo info = AllocInfo::GetInChunk(aPtr, chunk, pageind);
+ MOZ_ASSERT(info.IsValid());
+ MaybePoison(aPtr, info.Size());
+ }
+
+ arena_chunk_t* chunk_dealloc_delay = nullptr;
+
+ {
+ MutexAutoLock lock(arena->mLock);
+ arena_chunk_map_t* mapelm = &chunk->map[pageind];
+ MOZ_RELEASE_ASSERT((mapelm->bits & CHUNK_MAP_DECOMMITTED) == 0,
+ "Freeing in decommitted page.");
+ MOZ_RELEASE_ASSERT((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0,
+ "Double-free?");
+ if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
+ // Small allocation.
+ chunk_dealloc_delay = arena->DallocSmall(chunk, aPtr, mapelm);
+ } else {
+ // Large allocation.
+ chunk_dealloc_delay = arena->DallocLarge(chunk, aPtr);
+ }
+ }
+
+ if (chunk_dealloc_delay) {
+ chunk_dealloc((void*)chunk_dealloc_delay, kChunkSize, ARENA_CHUNK);
+ }
+}
+
+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 - 1 &&
+ (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) {
+ MaybePoison((void*)(uintptr_t(aPtr) + aSize), 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.
+ MaybePoison((void*)((uintptr_t)aPtr + aSize), 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. Allow non-private arenas to switch arenas.
+ ret = (mIsPrivate ? this : choose_arena(aSize))->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);
+}
+
+void* arena_t::operator new(size_t aCount, const fallible_t&) noexcept {
+ MOZ_ASSERT(aCount == sizeof(arena_t));
+ return TypedBaseAlloc<arena_t>::alloc();
+}
+
+void arena_t::operator delete(void* aPtr) {
+ TypedBaseAlloc<arena_t>::dealloc((arena_t*)aPtr);
+}
+
+arena_t::arena_t(arena_params_t* aParams, bool aIsPrivate) {
+ unsigned i;
+
+ MOZ_RELEASE_ASSERT(mLock.Init());
+
+ memset(&mLink, 0, sizeof(mLink));
+ memset(&mStats, 0, sizeof(arena_stats_t));
+ mId = 0;
+
+ // Initialize chunks.
+ mChunksDirty.Init();
+#ifdef MALLOC_DOUBLE_PURGE
+ new (&mChunksMAdvised) DoublyLinkedList<arena_chunk_t>();
+#endif
+ mSpare = nullptr;
+
+ mRandomizeSmallAllocations = opt_randomize_small;
+ if (aParams) {
+ uint32_t flags = aParams->mFlags & ARENA_FLAG_RANDOMIZE_SMALL_MASK;
+ switch (flags) {
+ case ARENA_FLAG_RANDOMIZE_SMALL_ENABLED:
+ mRandomizeSmallAllocations = true;
+ break;
+ case ARENA_FLAG_RANDOMIZE_SMALL_DISABLED:
+ mRandomizeSmallAllocations = false;
+ break;
+ case ARENA_FLAG_RANDOMIZE_SMALL_DEFAULT:
+ default:
+ break;
+ }
+
+ mMaxDirtyIncreaseOverride = aParams->mMaxDirtyIncreaseOverride;
+ mMaxDirtyDecreaseOverride = aParams->mMaxDirtyDecreaseOverride;
+ } else {
+ mMaxDirtyIncreaseOverride = 0;
+ mMaxDirtyDecreaseOverride = 0;
+ }
+
+ mPRNG = nullptr;
+
+ mIsPrivate = aIsPrivate;
+
+ 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 gMaxBinClass for now.
+ if (sizeClass.Size() == gMaxBinClass) {
+ break;
+ }
+ sizeClass = sizeClass.Next();
+ }
+ MOZ_ASSERT(i == NUM_SMALL_CLASSES - 1);
+
+#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED)
+ mMagic = ARENA_MAGIC;
+#endif
+}
+
+arena_t::~arena_t() {
+ size_t i;
+ MutexAutoLock lock(mLock);
+ MOZ_RELEASE_ASSERT(!mLink.Left() && !mLink.Right(),
+ "Arena is still registered");
+ MOZ_RELEASE_ASSERT(!mStats.allocated_small && !mStats.allocated_large,
+ "Arena is not empty");
+ if (mSpare) {
+ chunk_dealloc(mSpare, kChunkSize, ARENA_CHUNK);
+ }
+ for (i = 0; i < NUM_SMALL_CLASSES; i++) {
+ MOZ_RELEASE_ASSERT(!mBins[i].mNonFullRuns.First(), "Bin is not empty");
+ }
+#ifdef MOZ_DEBUG
+ {
+ MutexAutoLock lock(huge_mtx);
+ // This is an expensive check, so we only do it on debug builds.
+ for (auto node : huge.iter()) {
+ MOZ_RELEASE_ASSERT(node->mArenaId != mId, "Arena has huge allocations");
+ }
+ }
+#endif
+ mId = 0;
+}
+
+arena_t* ArenaCollection::CreateArena(bool aIsPrivate,
+ arena_params_t* aParams) {
+ arena_t* ret = new (fallible) arena_t(aParams, aIsPrivate);
+ 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);
+
+ // For public arenas, it's fine to just use incrementing arena id
+ if (!aIsPrivate) {
+ ret->mId = mLastPublicArenaId++;
+ mArenas.Insert(ret);
+ return ret;
+ }
+
+ // For private arenas, generate a cryptographically-secure random id for the
+ // new arena. If an attacker manages to get control of the process, this
+ // should make it more difficult for them to "guess" the ID of a memory
+ // arena, stopping them from getting data they may want
+
+ while (true) {
+ mozilla::Maybe<uint64_t> maybeRandomId = mozilla::RandomUint64();
+ MOZ_RELEASE_ASSERT(maybeRandomId.isSome());
+
+ // Avoid 0 as an arena Id. We use 0 for disposed arenas.
+ if (!maybeRandomId.value()) {
+ continue;
+ }
+
+ // Keep looping until we ensure that the random number we just generated
+ // isn't already in use by another active arena
+ arena_t* existingArena =
+ GetByIdInternal(maybeRandomId.value(), true /*aIsPrivate*/);
+
+ if (!existingArena) {
+ ret->mId = static_cast<arena_id_t>(maybeRandomId.value());
+ mPrivateArenas.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;
+
+ // We're going to configure guard pages in the region between the
+ // page-aligned size and the chunk-aligned size, so if those are the same
+ // then we need to force that region into existence.
+ csize = CHUNK_CEILING(aSize + gPageSize);
+ if (csize < aSize) {
+ // size is large enough to cause size_t wrap-around.
+ return nullptr;
+ }
+
+ // Allocate an extent node with which to track the chunk.
+ node = ExtentAlloc::alloc();
+ if (!node) {
+ return nullptr;
+ }
+
+ // Allocate one or more contiguous chunks for this request.
+ ret = chunk_alloc(csize, aAlignment, false, &zeroed);
+ if (!ret) {
+ ExtentAlloc::dealloc(node);
+ return nullptr;
+ }
+ psize = PAGE_CEILING(aSize);
+ if (aZero) {
+ // We will decommit anything past psize so there is no need to zero
+ // further.
+ chunk_ensure_zero(ret, psize, zeroed);
+ }
+
+ // Insert node into huge.
+ node->mAddr = ret;
+ node->mSize = psize;
+ node->mArena = this;
+ node->mArenaId = mId;
+
+ {
+ 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;
+ }
+
+ pages_decommit((void*)((uintptr_t)ret + psize), csize - psize);
+
+ if (!aZero) {
+ ApplyZeroOrJunk(ret, psize);
+ }
+
+ 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 + gPageSize) == CHUNK_CEILING(aOldSize + gPageSize)) {
+ size_t psize = PAGE_CEILING(aSize);
+ if (aSize < aOldSize) {
+ MaybePoison((void*)((uintptr_t)aPtr + aSize), aOldSize - aSize);
+ }
+ 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;
+ }
+
+ // We 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().
+ 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. Allow non-private arenas to switch arenas.
+ ret = (mIsPrivate ? this : choose_arena(aSize))->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;
+ size_t mapped = 0;
+ {
+ 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);
+ // See AllocInfo::Arena.
+ MOZ_RELEASE_ASSERT(node->mArenaId == node->mArena->mId);
+ huge.Remove(node);
+
+ mapped = CHUNK_CEILING(node->mSize + gPageSize);
+ huge_allocated -= node->mSize;
+ huge_mapped -= mapped;
+ }
+
+ // Unmap chunk.
+ chunk_dealloc(node->mAddr, mapped, HUGE_CHUNK);
+
+ ExtentAlloc::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;
+
+ 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
+ const size_t 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 % result) {
+ _malloc_message(
+ _getprogname(),
+ "Compile-time page size does not divide the runtime one.\n");
+ MOZ_CRASH();
+ }
+#else
+ gRealPageSize = gPageSize = result;
+#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 MALLOC_RUNTIME_CONFIG
+ case 'j':
+ opt_junk = false;
+ break;
+ case 'J':
+ opt_junk = true;
+ break;
+ case 'q':
+ opt_poison = false;
+ break;
+ case 'Q':
+ opt_poison = true;
+ break;
+ case 'z':
+ opt_zero = false;
+ break;
+ case 'Z':
+ opt_zero = true;
+ break;
+# ifndef MALLOC_STATIC_PAGESIZE
+ case 'P':
+ if (gPageSize < 64_KiB) {
+ gPageSize <<= 1;
+ }
+ break;
+# endif
+#endif
+ case 'r':
+ opt_randomize_small = false;
+ break;
+ case 'R':
+ opt_randomize_small = true;
+ break;
+ default: {
+ char cbuf[2];
+
+ cbuf[0] = opts[i];
+ cbuf[1] = '\0';
+ _malloc_message(_getprogname(),
+ ": (malloc) Unsupported character "
+ "in malloc options: '",
+ cbuf, "'\n");
+ }
+ }
+ }
+ }
+ }
+
+#ifndef MALLOC_STATIC_PAGESIZE
+ DefineGlobals();
+#endif
+ gRecycledSize = 0;
+
+ // Initialize chunks data.
+ chunks_mtx.Init();
+ MOZ_PUSH_IGNORE_THREAD_SAFETY
+ gChunksBySize.Init();
+ gChunksByAddress.Init();
+ MOZ_POP_THREAD_SAFETY
+
+ // Initialize huge allocation data.
+ huge_mtx.Init();
+ MOZ_PUSH_IGNORE_THREAD_SAFETY
+ huge.Init();
+ huge_allocated = 0;
+ huge_mapped = 0;
+ MOZ_POP_THREAD_SAFETY
+
+ // Initialize base allocation data structures.
+ base_mtx.Init();
+ MOZ_PUSH_IGNORE_THREAD_SAFETY
+ base_mapped = 0;
+ base_committed = 0;
+ MOZ_POP_THREAD_SAFETY
+
+ // 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, /* aZero = */ 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, /* aZero = */ 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());
+ } else {
+ if (!malloc_init()) {
+ ret = nullptr;
+ } else {
+ arena_t* arena = mArena ? mArena : choose_arena(aSize);
+ ret = arena->Malloc(aSize, /* aZero = */ 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_internal(
+ jemalloc_stats_t* aStats, jemalloc_bin_stats_t* aBinStats) {
+ size_t non_arena_mapped, chunk_header_size;
+
+ if (!aStats) {
+ return;
+ }
+ if (!malloc_init()) {
+ memset(aStats, 0, sizeof(*aStats));
+ return;
+ }
+ if (aBinStats) {
+ memset(aBinStats, 0, sizeof(jemalloc_bin_stats_t) * NUM_SMALL_CLASSES);
+ }
+
+ // Gather runtime settings.
+ aStats->opt_junk = opt_junk;
+ aStats->opt_zero = opt_zero;
+ aStats->quantum = kQuantum;
+ aStats->quantum_max = kMaxQuantumClass;
+ aStats->quantum_wide = kQuantumWide;
+ aStats->quantum_wide_max = kMaxQuantumWideClass;
+ aStats->subpage_max = gMaxSubPageClass;
+ 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_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 < NUM_SMALL_CLASSES; j++) {
+ arena_bin_t* bin = &arena->mBins[j];
+ size_t bin_unused = 0;
+ size_t num_non_full_runs = 0;
+
+ for (auto mapelm : bin->mNonFullRuns.iter()) {
+ arena_run_t* run = (arena_run_t*)(mapelm->bits & ~gPageSizeMask);
+ bin_unused += run->mNumFree * bin->mSizeClass;
+ num_non_full_runs++;
+ }
+
+ if (bin->mCurrentRun) {
+ bin_unused += bin->mCurrentRun->mNumFree * bin->mSizeClass;
+ num_non_full_runs++;
+ }
+
+ arena_unused += bin_unused;
+ arena_headers += bin->mNumRuns * bin->mRunFirstRegionOffset;
+ if (aBinStats) {
+ aBinStats[j].size = bin->mSizeClass;
+ aBinStats[j].num_non_full_runs += num_non_full_runs;
+ aBinStats[j].num_runs += bin->mNumRuns;
+ aBinStats[j].bytes_unused += bin_unused;
+ size_t bytes_per_run = static_cast<size_t>(bin->mRunSizePages)
+ << gPageSize2Pow;
+ aBinStats[j].bytes_total +=
+ bin->mNumRuns * (bytes_per_run - bin->mRunFirstRegionOffset);
+ aBinStats[j].bytes_per_run = bytes_per_run;
+ }
+ }
+ }
+
+ MOZ_ASSERT(arena_mapped >= arena_committed);
+ MOZ_ASSERT(arena_committed >= arena_allocated + arena_dirty);
+
+ aStats->mapped += arena_mapped;
+ aStats->allocated += arena_allocated;
+ aStats->page_cache += arena_dirty;
+ // "waste" is committed memory that is neither dirty nor
+ // allocated. If you change this definition please update
+ // memory/replace/logalloc/replay/Replay.cpp's jemalloc_stats calculation of
+ // committed.
+ 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);
+}
+
+template <>
+inline size_t MozJemalloc::jemalloc_stats_num_bins() {
+ return NUM_SMALL_CLASSES;
+}
+
+#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(1);
+ }
+ }
+}
+
+inline arena_t* ArenaCollection::GetByIdInternal(arena_id_t aArenaId,
+ bool aIsPrivate) {
+ // 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;
+ return (aIsPrivate ? mPrivateArenas : mArenas).Search(key.addr());
+}
+
+inline arena_t* ArenaCollection::GetById(arena_id_t aArenaId, bool aIsPrivate) {
+ if (!malloc_initialized) {
+ return nullptr;
+ }
+
+ MutexAutoLock lock(mLock);
+ arena_t* result = GetByIdInternal(aArenaId, aIsPrivate);
+ MOZ_RELEASE_ASSERT(result);
+ return result;
+}
+
+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);
+}
+
+template <>
+inline void MozJemalloc::moz_set_max_dirty_page_modifier(int32_t aModifier) {
+ gArenas.SetDefaultMaxDirtyPageModifier(aModifier);
+}
+
+#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"
+
+// End non-standard functions.
+// ***************************************************************************
+#ifndef XP_WIN
+// 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.
+FORK_HOOK
+void _malloc_prefork(void) MOZ_NO_THREAD_SAFETY_ANALYSIS {
+ // Acquire all mutexes in a safe order.
+ gArenas.mLock.Lock();
+
+ for (auto arena : gArenas.iter()) {
+ arena->mLock.Lock();
+ }
+
+ base_mtx.Lock();
+
+ huge_mtx.Lock();
+}
+
+FORK_HOOK
+void _malloc_postfork_parent(void) MOZ_NO_THREAD_SAFETY_ANALYSIS {
+ // 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();
+}
+
+FORK_HOOK
+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();
+}
+#endif // XP_WIN
+
+// 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,
+
+// The default malloc table, i.e. plain allocations. It never changes. It's
+// used by init(), and not used after that.
+static const malloc_table_t gDefaultMallocTable = {
+# include "malloc_decls.h"
+};
+
+// The malloc table installed by init(). It never changes from that point
+// onward. It will be the same as gDefaultMallocTable if no replace-malloc tool
+// is enabled at startup.
+static malloc_table_t gOriginalMallocTable = {
+# include "malloc_decls.h"
+};
+
+// The malloc table installed by jemalloc_replace_dynamic(). (Read the
+// comments above that function for more details.)
+static malloc_table_t gDynamicMallocTable = {
+# include "malloc_decls.h"
+};
+
+// This briefly points to gDefaultMallocTable at startup. After that, it points
+// to either gOriginalMallocTable or gDynamicMallocTable. It's atomic to avoid
+// races when switching between tables.
+static Atomic<malloc_table_t const*, mozilla::MemoryOrdering::Relaxed>
+ gMallocTablePtr;
+
+# 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() {
+ wchar_t replace_malloc_lib[1024];
+ if (GetEnvironmentVariableW(L"MOZ_REPLACE_MALLOC_LIB", replace_malloc_lib,
+ ArrayLength(replace_malloc_lib)) > 0) {
+ return LoadLibraryW(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(malloc_table_t*);
+
+# ifdef MOZ_REPLACE_MALLOC_STATIC
+extern "C" void logalloc_init(malloc_table_t*, ReplaceMallocBridge**);
+
+extern "C" void dmd_init(malloc_table_t*, ReplaceMallocBridge**);
+
+extern "C" void phc_init(malloc_table_t*, ReplaceMallocBridge**);
+# endif
+
+bool Equals(const malloc_table_t& aTable1, const 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 ReplaceMallocBridge* gReplaceMallocBridge = nullptr;
+static void init() {
+ malloc_table_t tempTable = gDefaultMallocTable;
+
+# 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.
+ gMallocTablePtr = &gDefaultMallocTable;
+
+ // Pass in the default allocator table so replace functions can copy and use
+ // it for their allocations. The replace_init() function should modify the
+ // table if it wants to be active, otherwise leave it unmodified.
+ if (replace_init) {
+ replace_init(&tempTable, &gReplaceMallocBridge);
+ }
+# ifdef MOZ_REPLACE_MALLOC_STATIC
+ if (Equals(tempTable, gDefaultMallocTable)) {
+ logalloc_init(&tempTable, &gReplaceMallocBridge);
+ }
+# ifdef MOZ_DMD
+ if (Equals(tempTable, gDefaultMallocTable)) {
+ dmd_init(&tempTable, &gReplaceMallocBridge);
+ }
+# endif
+# ifdef MOZ_PHC
+ if (Equals(tempTable, gDefaultMallocTable)) {
+ phc_init(&tempTable, &gReplaceMallocBridge);
+ }
+# endif
+# endif
+ if (!Equals(tempTable, gDefaultMallocTable)) {
+ replace_malloc_init_funcs(&tempTable);
+ }
+ gOriginalMallocTable = tempTable;
+ gMallocTablePtr = &gOriginalMallocTable;
+}
+
+// WARNING WARNING WARNING: this function should be used with extreme care. It
+// is not as general-purpose as it looks. It is currently used by
+// tools/profiler/core/memory_hooks.cpp for counting allocations and probably
+// should not be used for any other purpose.
+//
+// This function allows the original malloc table to be temporarily replaced by
+// a different malloc table. Or, if the argument is nullptr, it switches back to
+// the original malloc table.
+//
+// Limitations:
+//
+// - It is not threadsafe. If multiple threads pass it the same
+// `replace_init_func` at the same time, there will be data races writing to
+// the malloc_table_t within that function.
+//
+// - Only one replacement can be installed. No nesting is allowed.
+//
+// - The new malloc table must be able to free allocations made by the original
+// malloc table, and upon removal the original malloc table must be able to
+// free allocations made by the new malloc table. This means the new malloc
+// table can only do simple things like recording extra information, while
+// delegating actual allocation/free operations to the original malloc table.
+//
+MOZ_JEMALLOC_API void jemalloc_replace_dynamic(
+ jemalloc_init_func replace_init_func) {
+ if (replace_init_func) {
+ malloc_table_t tempTable = gOriginalMallocTable;
+ (*replace_init_func)(&tempTable, &gReplaceMallocBridge);
+ if (!Equals(tempTable, gOriginalMallocTable)) {
+ replace_malloc_init_funcs(&tempTable);
+
+ // Temporarily switch back to the original malloc table. In the
+ // (supported) non-nested case, this is a no-op. But just in case this is
+ // a (unsupported) nested call, it makes the overwriting of
+ // gDynamicMallocTable less racy, because ongoing calls to malloc() and
+ // friends won't go through gDynamicMallocTable.
+ gMallocTablePtr = &gOriginalMallocTable;
+
+ gDynamicMallocTable = tempTable;
+ gMallocTablePtr = &gDynamicMallocTable;
+ // We assume that dynamic replaces don't occur close enough for a
+ // thread to still have old copies of the table pointer when the 2nd
+ // replace occurs.
+ }
+ } else {
+ // Switch back to the original malloc table.
+ gMallocTablePtr = &gOriginalMallocTable;
+ }
+}
+
+# define MALLOC_DECL(name, return_type, ...) \
+ template <> \
+ inline return_type ReplaceMalloc::name( \
+ ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) { \
+ if (MOZ_UNLIKELY(!gMallocTablePtr)) { \
+ init(); \
+ } \
+ return (*gMallocTablePtr).name(ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
+ }
+# include "malloc_decls.h"
+
+MOZ_JEMALLOC_API struct ReplaceMallocBridge* get_bridge(void) {
+ if (MOZ_UNLIKELY(!gMallocTablePtr)) {
+ 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(malloc_table_t* table) {
+ if (table->posix_memalign == MozJemalloc::posix_memalign &&
+ table->memalign != MozJemalloc::memalign) {
+ table->posix_memalign =
+ AlignedAllocator<ReplaceMalloc::memalign>::posix_memalign;
+ }
+ if (table->aligned_alloc == MozJemalloc::aligned_alloc &&
+ table->memalign != MozJemalloc::memalign) {
+ table->aligned_alloc =
+ AlignedAllocator<ReplaceMalloc::memalign>::aligned_alloc;
+ }
+ if (table->valloc == MozJemalloc::valloc &&
+ table->memalign != MozJemalloc::memalign) {
+ table->valloc = AlignedAllocator<ReplaceMalloc::memalign>::valloc;
+ }
+ if (table->moz_create_arena_with_params ==
+ MozJemalloc::moz_create_arena_with_params &&
+ table->malloc != MozJemalloc::malloc) {
+# define MALLOC_DECL(name, ...) \
+ table->name = DummyArenaAllocator<ReplaceMalloc>::name;
+# define MALLOC_FUNCS MALLOC_FUNCS_ARENA_BASE
+# include "malloc_decls.h"
+ }
+ if (table->moz_arena_malloc == MozJemalloc::moz_arena_malloc &&
+ table->malloc != MozJemalloc::malloc) {
+# define MALLOC_DECL(name, ...) \
+ table->name = DummyArenaAllocator<ReplaceMalloc>::name;
+# define MALLOC_FUNCS MALLOC_FUNCS_ARENA_ALLOC
+# include "malloc_decls.h"
+ }
+}
+
+#endif // MOZ_REPLACE_MALLOC
+// ***************************************************************************
+// Definition of all the _impl functions
+// GENERIC_MALLOC_DECL2_MINGW is only used for the MinGW build, and aliases
+// the malloc funcs (e.g. malloc) to the je_ versions. It does not generate
+// aliases for the other functions (jemalloc and arena functions).
+//
+// We do need aliases for the other mozglue.def-redirected functions though,
+// these are done at the bottom of mozmemory_wrap.cpp
+#define GENERIC_MALLOC_DECL2_MINGW(name, name_impl, return_type, ...) \
+ return_type name(ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) \
+ __attribute__((alias(MOZ_STRINGIFY(name_impl))));
+
+#define GENERIC_MALLOC_DECL2(attributes, name, name_impl, return_type, ...) \
+ return_type name_impl(ARGS_HELPER(TYPED_ARGS, ##__VA_ARGS__)) attributes { \
+ return DefaultMalloc::name(ARGS_HELPER(ARGS, ##__VA_ARGS__)); \
+ }
+
+#ifndef __MINGW32__
+# define GENERIC_MALLOC_DECL(attributes, name, return_type, ...) \
+ GENERIC_MALLOC_DECL2(attributes, name, name##_impl, return_type, \
+ ##__VA_ARGS__)
+#else
+# define GENERIC_MALLOC_DECL(attributes, name, return_type, ...) \
+ GENERIC_MALLOC_DECL2(attributes, name, name##_impl, return_type, \
+ ##__VA_ARGS__) \
+ GENERIC_MALLOC_DECL2_MINGW(name, name##_impl, return_type, ##__VA_ARGS__)
+#endif
+
+#define NOTHROW_MALLOC_DECL(...) \
+ MOZ_MEMORY_API MACRO_CALL(GENERIC_MALLOC_DECL, (noexcept(true), __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(attributes, name, return_type, ...) \
+ GENERIC_MALLOC_DECL2(attributes, 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
+MOZ_EXPORT 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.
+MOZ_EXPORT void* _expand(void* aPtr, size_t newsize) {
+ if (AllocInfo::Get(aPtr).Size() >= newsize) {
+ return aPtr;
+ }
+
+ return nullptr;
+}
+
+MOZ_EXPORT size_t _msize(void* aPtr) {
+ return DefaultMalloc::malloc_usable_size(aPtr);
+}
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 07:21:38 +0000