mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-06 00:55:37 +00:00
140 lines
2.7 KiB
C++
140 lines
2.7 KiB
C++
/* 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/. */
|
|
|
|
#include "VolatileBuffer.h"
|
|
#include "mozilla/Assertions.h"
|
|
#include "mozilla/mozalloc.h"
|
|
|
|
#include <fcntl.h>
|
|
#include <linux/ashmem.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
#ifdef MOZ_MEMORY
|
|
extern "C" int posix_memalign(void** memptr, size_t alignment, size_t size);
|
|
#endif
|
|
|
|
#define MIN_VOLATILE_ALLOC_SIZE 8192
|
|
|
|
namespace mozilla {
|
|
|
|
VolatileBuffer::VolatileBuffer()
|
|
: mMutex("VolatileBuffer")
|
|
, mBuf(nullptr)
|
|
, mSize(0)
|
|
, mLockCount(0)
|
|
, mFd(-1)
|
|
{
|
|
}
|
|
|
|
bool
|
|
VolatileBuffer::Init(size_t aSize, size_t aAlignment)
|
|
{
|
|
MOZ_ASSERT(!mSize && !mBuf, "Init called twice");
|
|
MOZ_ASSERT(!(aAlignment % sizeof(void *)),
|
|
"Alignment must be multiple of pointer size");
|
|
|
|
mSize = aSize;
|
|
if (aSize < MIN_VOLATILE_ALLOC_SIZE) {
|
|
goto heap_alloc;
|
|
}
|
|
|
|
mFd = open("/" ASHMEM_NAME_DEF, O_RDWR);
|
|
if (mFd < 0) {
|
|
goto heap_alloc;
|
|
}
|
|
|
|
if (ioctl(mFd, ASHMEM_SET_SIZE, mSize) < 0) {
|
|
goto heap_alloc;
|
|
}
|
|
|
|
mBuf = mmap(nullptr, mSize, PROT_READ | PROT_WRITE, MAP_SHARED, mFd, 0);
|
|
if (mBuf != MAP_FAILED) {
|
|
return true;
|
|
}
|
|
|
|
heap_alloc:
|
|
mBuf = nullptr;
|
|
if (mFd >= 0) {
|
|
close(mFd);
|
|
mFd = -1;
|
|
}
|
|
|
|
#ifdef MOZ_MEMORY
|
|
posix_memalign(&mBuf, aAlignment, aSize);
|
|
#else
|
|
mBuf = memalign(aAlignment, aSize);
|
|
#endif
|
|
return !!mBuf;
|
|
}
|
|
|
|
VolatileBuffer::~VolatileBuffer()
|
|
{
|
|
MOZ_ASSERT(mLockCount == 0, "Being destroyed with non-zero lock count?");
|
|
|
|
if (OnHeap()) {
|
|
free(mBuf);
|
|
} else {
|
|
munmap(mBuf, mSize);
|
|
close(mFd);
|
|
}
|
|
}
|
|
|
|
bool
|
|
VolatileBuffer::Lock(void** aBuf)
|
|
{
|
|
MutexAutoLock lock(mMutex);
|
|
|
|
MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
|
|
|
|
*aBuf = mBuf;
|
|
if (++mLockCount > 1 || OnHeap()) {
|
|
return true;
|
|
}
|
|
|
|
// Zero offset and zero length means we want to pin/unpin the entire thing.
|
|
struct ashmem_pin pin = { 0, 0 };
|
|
return ioctl(mFd, ASHMEM_PIN, &pin) == ASHMEM_NOT_PURGED;
|
|
}
|
|
|
|
void
|
|
VolatileBuffer::Unlock()
|
|
{
|
|
MutexAutoLock lock(mMutex);
|
|
|
|
MOZ_ASSERT(mLockCount > 0, "VolatileBuffer unlocked too many times!");
|
|
if (--mLockCount || OnHeap()) {
|
|
return;
|
|
}
|
|
|
|
struct ashmem_pin pin = { 0, 0 };
|
|
ioctl(mFd, ASHMEM_UNPIN, &pin);
|
|
}
|
|
|
|
bool
|
|
VolatileBuffer::OnHeap() const
|
|
{
|
|
return mFd < 0;
|
|
}
|
|
|
|
size_t
|
|
VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
|
|
{
|
|
return OnHeap() ? aMallocSizeOf(mBuf) : 0;
|
|
}
|
|
|
|
size_t
|
|
VolatileBuffer::NonHeapSizeOfExcludingThis() const
|
|
{
|
|
if (OnHeap()) {
|
|
return 0;
|
|
}
|
|
|
|
return (mSize + (PAGE_SIZE - 1)) & PAGE_MASK;
|
|
}
|
|
|
|
} // namespace mozilla
|