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BufferQueue: release mutex while allocating. 

BufferQueueProducer::allocateBuffers used to keep the BufferQueueCore
mutex while doing the buffer allocation, which would cause the consumer
(which also needs the mutex) to block if the allocation takes a long
time.
Instead, release the mutex while doing the allocation, and grab it again
before filling the slots. Keep a bool state and a condvar to prevent
other producers from trying to allocate the slots while the mutex is
released.

Bug: 11792166

Change-Id: I4ab1319995ef892be2beba892f1fdbf50ce0416d
This commit is contained in:
Antoine Labour 2014-07-15 21:17:03 -07:00
parent 134a6a2594
commit ea96044470
3 changed files with 116 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/gui/BufferQueueCore.h
View File

@ -120,6 +120,9 @@ private:
// in one of the slots.
bool stillTracking(const BufferItem* item) const;
// waitWhileAllocatingLocked blocks until mIsAllocating is false.
void waitWhileAllocatingLocked() const;
// mAllocator is the connection to SurfaceFlinger that is used to allocate
// new GraphicBuffer objects.
sp<IGraphicBufferAlloc> mAllocator;
@ -234,6 +237,15 @@ private:
// mSidebandStream is a handle to the sideband buffer stream, if any
sp<NativeHandle> mSidebandStream;
// mIsAllocating indicates whether a producer is currently trying to allocate buffers (which
// releases mMutex while doing the allocation proper). Producers should not modify any of the
// FREE slots while this is true. mIsAllocatingCondition is signaled when this value changes to
// false.
bool mIsAllocating;
// mIsAllocatingCondition is a condition variable used by producers to wait until mIsAllocating
// becomes false.
mutable Condition mIsAllocatingCondition;
}; // class BufferQueueCore
} // namespace android

11
libs/gui/BufferQueueCore.cpp
View File

@ -64,7 +64,9 @@ BufferQueueCore::BufferQueueCore(const sp<IGraphicBufferAlloc>& allocator) :
mMaxAcquiredBufferCount(1),
mBufferHasBeenQueued(false),
mFrameCounter(0),
mTransformHint(0)
mTransformHint(0),
mIsAllocating(false),
mIsAllocatingCondition()
{
if (allocator == NULL) {
sp<ISurfaceComposer> composer(ComposerService::getComposerService());
@ -226,4 +228,11 @@ bool BufferQueueCore::stillTracking(const BufferItem* item) const {
(item->mGraphicBuffer->handle == slot.mGraphicBuffer->handle);
}
void BufferQueueCore::waitWhileAllocatingLocked() const {
ATRACE_CALL();
while (mIsAllocating) {
mIsAllocatingCondition.wait(mMutex);
}
}
} // namespace android

137
libs/gui/BufferQueueProducer.cpp
View File

@ -74,6 +74,7 @@ status_t BufferQueueProducer::setBufferCount(int bufferCount) {
sp<IConsumerListener> listener;
{ // Autolock scope
Mutex::Autolock lock(mCore->mMutex);
mCore->waitWhileAllocatingLocked();
if (mCore->mIsAbandoned) {
BQ_LOGE("setBufferCount: BufferQueue has been abandoned");
@ -266,6 +267,7 @@ status_t BufferQueueProducer::dequeueBuffer(int *outSlot,
{ // Autolock scope
Mutex::Autolock lock(mCore->mMutex);
mCore->waitWhileAllocatingLocked();
if (format == 0) {
format = mCore->mDefaultBufferFormat;
@ -424,6 +426,7 @@ status_t BufferQueueProducer::detachNextBuffer(sp<GraphicBuffer>* outBuffer,
}
Mutex::Autolock lock(mCore->mMutex);
mCore->waitWhileAllocatingLocked();
if (mCore->mIsAbandoned) {
BQ_LOGE("detachNextBuffer: BufferQueue has been abandoned");
@ -468,6 +471,7 @@ status_t BufferQueueProducer::attachBuffer(int* outSlot,
}
Mutex::Autolock lock(mCore->mMutex);
mCore->waitWhileAllocatingLocked();
status_t returnFlags = NO_ERROR;
int found;
@ -796,6 +800,7 @@ status_t BufferQueueProducer::disconnect(int api) {
sp<IConsumerListener> listener;
{ // Autolock scope
Mutex::Autolock lock(mCore->mMutex);
mCore->waitWhileAllocatingLocked();
if (mCore->mIsAbandoned) {
// It's not really an error to disconnect after the surface has
@ -862,55 +867,101 @@ status_t BufferQueueProducer::setSidebandStream(const sp<NativeHandle>& stream)
void BufferQueueProducer::allocateBuffers(bool async, uint32_t width,
uint32_t height, uint32_t format, uint32_t usage) {
Vector<int> freeSlots;
ATRACE_CALL();
while (true) {
Vector<int> freeSlots;
size_t newBufferCount = 0;
uint32_t allocWidth = 0;
uint32_t allocHeight = 0;
uint32_t allocFormat = 0;
uint32_t allocUsage = 0;
{ // Autolock scope
Mutex::Autolock lock(mCore->mMutex);
mCore->waitWhileAllocatingLocked();
Mutex::Autolock lock(mCore->mMutex);
int currentBufferCount = 0;
for (int slot = 0; slot < BufferQueueDefs::NUM_BUFFER_SLOTS; ++slot) {
if (mSlots[slot].mGraphicBuffer != NULL) {
++currentBufferCount;
} else {
if (mSlots[slot].mBufferState != BufferSlot::FREE) {
BQ_LOGE("allocateBuffers: slot %d without buffer is not FREE",
slot);
continue;
}
int currentBufferCount = 0;
for (int slot = 0; slot < BufferQueueDefs::NUM_BUFFER_SLOTS; ++slot) {
if (mSlots[slot].mGraphicBuffer != NULL) {
++currentBufferCount;
} else {
if (mSlots[slot].mBufferState != BufferSlot::FREE) {
BQ_LOGE("allocateBuffers: slot %d without buffer is not FREE",
slot);
freeSlots.push_front(slot);
}
}
int maxBufferCount = mCore->getMaxBufferCountLocked(async);
BQ_LOGV("allocateBuffers: allocating from %d buffers up to %d buffers",
currentBufferCount, maxBufferCount);
if (maxBufferCount <= currentBufferCount)
return;
newBufferCount = maxBufferCount - currentBufferCount;
if (freeSlots.size() < newBufferCount) {
BQ_LOGE("allocateBuffers: ran out of free slots");
return;
}
allocWidth = width > 0 ? width : mCore->mDefaultWidth;
allocHeight = height > 0 ? height : mCore->mDefaultHeight;
allocFormat = format != 0 ? format : mCore->mDefaultBufferFormat;
allocUsage = usage | mCore->mConsumerUsageBits;
mCore->mIsAllocating = true;
} // Autolock scope
Vector<sp<GraphicBuffer> > buffers;
for (size_t i = 0; i < newBufferCount; ++i) {
status_t result = NO_ERROR;
sp<GraphicBuffer> graphicBuffer(mCore->mAllocator->createGraphicBuffer(
allocWidth, allocHeight, allocFormat, allocUsage, &result));
if (result != NO_ERROR) {
BQ_LOGE("allocateBuffers: failed to allocate buffer (%u x %u, format"
" %u, usage %u)", width, height, format, usage);
Mutex::Autolock lock(mCore->mMutex);
mCore->mIsAllocating = false;
mCore->mIsAllocatingCondition.broadcast();
return;
}
buffers.push_back(graphicBuffer);
}
{ // Autolock scope
Mutex::Autolock lock(mCore->mMutex);
uint32_t checkWidth = width > 0 ? width : mCore->mDefaultWidth;
uint32_t checkHeight = height > 0 ? height : mCore->mDefaultHeight;
uint32_t checkFormat = format != 0 ? format : mCore->mDefaultBufferFormat;
uint32_t checkUsage = usage | mCore->mConsumerUsageBits;
if (checkWidth != allocWidth || checkHeight != allocHeight ||
checkFormat != allocFormat || checkUsage != allocUsage) {
// Something changed while we released the lock. Retry.
BQ_LOGV("allocateBuffers: size/format/usage changed while allocating. Retrying.");
mCore->mIsAllocating = false;
mCore->mIsAllocatingCondition.broadcast();
continue;
}
freeSlots.push_front(slot);
}
}
for (size_t i = 0; i < newBufferCount; ++i) {
int slot = freeSlots[i];
if (mSlots[slot].mBufferState != BufferSlot::FREE) {
// A consumer allocated the FREE slot with attachBuffer. Discard the buffer we
// allocated.
BQ_LOGV("allocateBuffers: slot %d was acquired while allocating. "
"Dropping allocated buffer.", slot);
continue;
}
mCore->freeBufferLocked(slot); // Clean up the slot first
mSlots[slot].mGraphicBuffer = buffers[i];
mSlots[slot].mFrameNumber = 0;
mSlots[slot].mFence = Fence::NO_FENCE;
BQ_LOGV("allocateBuffers: allocated a new buffer in slot %d", slot);
}
int maxBufferCount = mCore->getMaxBufferCountLocked(async);
BQ_LOGV("allocateBuffers: allocating from %d buffers up to %d buffers",
currentBufferCount, maxBufferCount);
for (; currentBufferCount < maxBufferCount; ++currentBufferCount) {
if (freeSlots.empty()) {
BQ_LOGE("allocateBuffers: ran out of free slots");
return;
}
width = width > 0 ? width : mCore->mDefaultWidth;
height = height > 0 ? height : mCore->mDefaultHeight;
format = format != 0 ? format : mCore->mDefaultBufferFormat;
usage |= mCore->mConsumerUsageBits;
status_t result = NO_ERROR;
sp<GraphicBuffer> graphicBuffer(mCore->mAllocator->createGraphicBuffer(
width, height, format, usage, &result));
if (result != NO_ERROR) {
BQ_LOGE("allocateBuffers: failed to allocate buffer (%u x %u, format"
" %u, usage %u)", width, height, format, usage);
return;
}
int slot = freeSlots[freeSlots.size() - 1];
mCore->freeBufferLocked(slot); // Clean up the slot first
mSlots[slot].mGraphicBuffer = graphicBuffer;
mSlots[slot].mFrameNumber = 0;
mSlots[slot].mFence = Fence::NO_FENCE;
BQ_LOGV("allocateBuffers: allocated a new buffer in slot %d", slot);
freeSlots.pop();
mCore->mIsAllocating = false;
mCore->mIsAllocatingCondition.broadcast();
} // Autolock scope
}
}