memory/mozalloc/VolatileBufferAshmem.cpp@b8a032363ba2 (annotated)
memory/mozalloc/VolatileBufferAshmem.cpp
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 4 | |
| michael@0 | 5 | #include "VolatileBuffer.h" |
| michael@0 | 6 | #include "mozilla/Assertions.h" |
| michael@0 | 7 | #include "mozilla/NullPtr.h" |
| michael@0 | 8 | #include "mozilla/mozalloc.h" |
| michael@0 | 9 | |
| michael@0 | 10 | #include <fcntl.h> |
| michael@0 | 11 | #include <linux/ashmem.h> |
| michael@0 | 12 | #include <sys/mman.h> |
| michael@0 | 13 | #include <sys/stat.h> |
| michael@0 | 14 | #include <sys/types.h> |
| michael@0 | 15 | #include <unistd.h> |
| michael@0 | 16 | |
| michael@0 | 17 | #ifdef MOZ_MEMORY |
| michael@0 | 18 | #ifdef MOZ_WIDGET_ANDROID |
| michael@0 | 19 | extern "C" int __wrap_posix_memalign(void** memptr, size_t alignment, size_t size); |
| michael@0 | 20 | #else |
| michael@0 | 21 | extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size); |
| michael@0 | 22 | #endif |
| michael@0 | 23 | #endif |
| michael@0 | 24 | |
| michael@0 | 25 | #define MIN_VOLATILE_ALLOC_SIZE 8192 |
| michael@0 | 26 | |
| michael@0 | 27 | namespace mozilla { |
| michael@0 | 28 | |
| michael@0 | 29 | VolatileBuffer::VolatileBuffer() |
| michael@0 | 30 | : mBuf(nullptr) |
| michael@0 | 31 | , mSize(0) |
| michael@0 | 32 | , mLockCount(0) |
| michael@0 | 33 | , mFd(-1) |
| michael@0 | 34 | { |
| michael@0 | 35 | } |
| michael@0 | 36 | |
| michael@0 | 37 | bool |
| michael@0 | 38 | VolatileBuffer::Init(size_t aSize, size_t aAlignment) |
| michael@0 | 39 | { |
| michael@0 | 40 | MOZ_ASSERT(!mSize && !mBuf, "Init called twice"); |
| michael@0 | 41 | MOZ_ASSERT(!(aAlignment % sizeof(void *)), |
| michael@0 | 42 | "Alignment must be multiple of pointer size"); |
| michael@0 | 43 | |
| michael@0 | 44 | mSize = aSize; |
| michael@0 | 45 | if (aSize < MIN_VOLATILE_ALLOC_SIZE) { |
| michael@0 | 46 | goto heap_alloc; |
| michael@0 | 47 | } |
| michael@0 | 48 | |
| michael@0 | 49 | mFd = open("/" ASHMEM_NAME_DEF, O_RDWR); |
| michael@0 | 50 | if (mFd < 0) { |
| michael@0 | 51 | goto heap_alloc; |
| michael@0 | 52 | } |
| michael@0 | 53 | |
| michael@0 | 54 | if (ioctl(mFd, ASHMEM_SET_SIZE, mSize) < 0) { |
| michael@0 | 55 | close(mFd); |
| michael@0 | 56 | mFd = -1; |
| michael@0 | 57 | goto heap_alloc; |
| michael@0 | 58 | } |
| michael@0 | 59 | |
| michael@0 | 60 | mBuf = mmap(nullptr, mSize, PROT_READ | PROT_WRITE, MAP_SHARED, mFd, 0); |
| michael@0 | 61 | if (mBuf != MAP_FAILED) { |
| michael@0 | 62 | return true; |
| michael@0 | 63 | } |
| michael@0 | 64 | |
| michael@0 | 65 | heap_alloc: |
| michael@0 | 66 | #ifdef MOZ_MEMORY |
| michael@0 | 67 | #ifdef MOZ_WIDGET_ANDROID |
| michael@0 | 68 | __wrap_posix_memalign(&mBuf, aAlignment, aSize); |
| michael@0 | 69 | #else |
| michael@0 | 70 | posix_memalign(&mBuf, aAlignment, aSize); |
| michael@0 | 71 | #endif |
| michael@0 | 72 | #else |
| michael@0 | 73 | mBuf = memalign(aAlignment, aSize); |
| michael@0 | 74 | #endif |
| michael@0 | 75 | return !!mBuf; |
| michael@0 | 76 | } |
| michael@0 | 77 | |
| michael@0 | 78 | VolatileBuffer::~VolatileBuffer() |
| michael@0 | 79 | { |
| michael@0 | 80 | if (OnHeap()) { |
| michael@0 | 81 | free(mBuf); |
| michael@0 | 82 | } else { |
| michael@0 | 83 | munmap(mBuf, mSize); |
| michael@0 | 84 | close(mFd); |
| michael@0 | 85 | } |
| michael@0 | 86 | } |
| michael@0 | 87 | |
| michael@0 | 88 | bool |
| michael@0 | 89 | VolatileBuffer::Lock(void** aBuf) |
| michael@0 | 90 | { |
| michael@0 | 91 | MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer"); |
| michael@0 | 92 | |
| michael@0 | 93 | *aBuf = mBuf; |
| michael@0 | 94 | if (++mLockCount > 1 || OnHeap()) { |
| michael@0 | 95 | return true; |
| michael@0 | 96 | } |
| michael@0 | 97 | |
| michael@0 | 98 | // Zero offset and zero length means we want to pin/unpin the entire thing. |
| michael@0 | 99 | struct ashmem_pin pin = { 0, 0 }; |
| michael@0 | 100 | return ioctl(mFd, ASHMEM_PIN, &pin) == ASHMEM_NOT_PURGED; |
| michael@0 | 101 | } |
| michael@0 | 102 | |
| michael@0 | 103 | void |
| michael@0 | 104 | VolatileBuffer::Unlock() |
| michael@0 | 105 | { |
| michael@0 | 106 | MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!"); |
| michael@0 | 107 | if (--mLockCount || OnHeap()) { |
| michael@0 | 108 | return; |
| michael@0 | 109 | } |
| michael@0 | 110 | |
| michael@0 | 111 | struct ashmem_pin pin = { 0, 0 }; |
| michael@0 | 112 | ioctl(mFd, ASHMEM_UNPIN, &pin); |
| michael@0 | 113 | } |
| michael@0 | 114 | |
| michael@0 | 115 | bool |
| michael@0 | 116 | VolatileBuffer::OnHeap() const |
| michael@0 | 117 | { |
| michael@0 | 118 | return mFd < 0; |
| michael@0 | 119 | } |
| michael@0 | 120 | |
| michael@0 | 121 | size_t |
| michael@0 | 122 | VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const |
| michael@0 | 123 | { |
| michael@0 | 124 | return OnHeap() ? aMallocSizeOf(mBuf) : 0; |
| michael@0 | 125 | } |
| michael@0 | 126 | |
| michael@0 | 127 | size_t |
| michael@0 | 128 | VolatileBuffer::NonHeapSizeOfExcludingThis() const |
| michael@0 | 129 | { |
| michael@0 | 130 | if (OnHeap()) { |
| michael@0 | 131 | return 0; |
| michael@0 | 132 | } |
| michael@0 | 133 | |
| michael@0 | 134 | return (mSize + (PAGE_SIZE - 1)) & PAGE_MASK; |
| michael@0 | 135 | } |
| michael@0 | 136 | |
| michael@0 | 137 | } // namespace mozilla |
