1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/memory/mozalloc/VolatileBufferAshmem.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,137 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#include "VolatileBuffer.h"
1.9 +#include "mozilla/Assertions.h"
1.10 +#include "mozilla/NullPtr.h"
1.11 +#include "mozilla/mozalloc.h"
1.12 +
1.13 +#include <fcntl.h>
1.14 +#include <linux/ashmem.h>
1.15 +#include <sys/mman.h>
1.16 +#include <sys/stat.h>
1.17 +#include <sys/types.h>
1.18 +#include <unistd.h>
1.19 +
1.20 +#ifdef MOZ_MEMORY
1.21 +#ifdef MOZ_WIDGET_ANDROID
1.22 +extern "C" int __wrap_posix_memalign(void** memptr, size_t alignment, size_t size);
1.23 +#else
1.24 +extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size);
1.25 +#endif
1.26 +#endif
1.27 +
1.28 +#define MIN_VOLATILE_ALLOC_SIZE 8192
1.29 +
1.30 +namespace mozilla {
1.31 +
1.32 +VolatileBuffer::VolatileBuffer()
1.33 + : mBuf(nullptr)
1.34 + , mSize(0)
1.35 + , mLockCount(0)
1.36 + , mFd(-1)
1.37 +{
1.38 +}
1.39 +
1.40 +bool
1.41 +VolatileBuffer::Init(size_t aSize, size_t aAlignment)
1.42 +{
1.43 + MOZ_ASSERT(!mSize && !mBuf, "Init called twice");
1.44 + MOZ_ASSERT(!(aAlignment % sizeof(void *)),
1.45 + "Alignment must be multiple of pointer size");
1.46 +
1.47 + mSize = aSize;
1.48 + if (aSize < MIN_VOLATILE_ALLOC_SIZE) {
1.49 + goto heap_alloc;
1.50 + }
1.51 +
1.52 + mFd = open("/" ASHMEM_NAME_DEF, O_RDWR);
1.53 + if (mFd < 0) {
1.54 + goto heap_alloc;
1.55 + }
1.56 +
1.57 + if (ioctl(mFd, ASHMEM_SET_SIZE, mSize) < 0) {
1.58 + close(mFd);
1.59 + mFd = -1;
1.60 + goto heap_alloc;
1.61 + }
1.62 +
1.63 + mBuf = mmap(nullptr, mSize, PROT_READ | PROT_WRITE, MAP_SHARED, mFd, 0);
1.64 + if (mBuf != MAP_FAILED) {
1.65 + return true;
1.66 + }
1.67 +
1.68 +heap_alloc:
1.69 +#ifdef MOZ_MEMORY
1.70 +#ifdef MOZ_WIDGET_ANDROID
1.71 + __wrap_posix_memalign(&mBuf, aAlignment, aSize);
1.72 +#else
1.73 + posix_memalign(&mBuf, aAlignment, aSize);
1.74 +#endif
1.75 +#else
1.76 + mBuf = memalign(aAlignment, aSize);
1.77 +#endif
1.78 + return !!mBuf;
1.79 +}
1.80 +
1.81 +VolatileBuffer::~VolatileBuffer()
1.82 +{
1.83 + if (OnHeap()) {
1.84 + free(mBuf);
1.85 + } else {
1.86 + munmap(mBuf, mSize);
1.87 + close(mFd);
1.88 + }
1.89 +}
1.90 +
1.91 +bool
1.92 +VolatileBuffer::Lock(void** aBuf)
1.93 +{
1.94 + MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
1.95 +
1.96 + *aBuf = mBuf;
1.97 + if (++mLockCount > 1 || OnHeap()) {
1.98 + return true;
1.99 + }
1.100 +
1.101 + // Zero offset and zero length means we want to pin/unpin the entire thing.
1.102 + struct ashmem_pin pin = { 0, 0 };
1.103 + return ioctl(mFd, ASHMEM_PIN, &pin) == ASHMEM_NOT_PURGED;
1.104 +}
1.105 +
1.106 +void
1.107 +VolatileBuffer::Unlock()
1.108 +{
1.109 + MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!");
1.110 + if (--mLockCount || OnHeap()) {
1.111 + return;
1.112 + }
1.113 +
1.114 + struct ashmem_pin pin = { 0, 0 };
1.115 + ioctl(mFd, ASHMEM_UNPIN, &pin);
1.116 +}
1.117 +
1.118 +bool
1.119 +VolatileBuffer::OnHeap() const
1.120 +{
1.121 + return mFd < 0;
1.122 +}
1.123 +
1.124 +size_t
1.125 +VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
1.126 +{
1.127 + return OnHeap() ? aMallocSizeOf(mBuf) : 0;
1.128 +}
1.129 +
1.130 +size_t
1.131 +VolatileBuffer::NonHeapSizeOfExcludingThis() const
1.132 +{
1.133 + if (OnHeap()) {
1.134 + return 0;
1.135 + }
1.136 +
1.137 + return (mSize + (PAGE_SIZE - 1)) & PAGE_MASK;
1.138 +}
1.139 +
1.140 +} // namespace mozilla
