Drain buffer release thread in binder callback
Bug: 294133380
Flag: com.android.graphics.libgui.flags.buffer_release_channel
Test: BLASTBufferQueueTest
Change-Id: Ife6abb1ad9253bda836f846907e9bfba225c3dc9
diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 49f4cba..fdc39ed 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -52,19 +52,18 @@
namespace {
#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
-// RAII wrapper to defer arbitrary work until the Deferred instance is deleted.
-template <class F>
-class Deferred {
+template <class Mutex>
+class UnlockGuard {
public:
- explicit Deferred(F f) : mF{std::move(f)} {}
+ explicit UnlockGuard(Mutex& lock) : mLock{lock} { mLock.unlock(); }
- ~Deferred() { mF(); }
+ ~UnlockGuard() { mLock.lock(); }
- Deferred(const Deferred&) = delete;
- Deferred& operator=(const Deferred&) = delete;
+ UnlockGuard(const UnlockGuard&) = delete;
+ UnlockGuard& operator=(const UnlockGuard&) = delete;
private:
- F mF;
+ Mutex& mLock;
};
#endif
@@ -271,9 +270,6 @@
void BLASTBufferQueue::onFirstRef() {
// safe default, most producers are expected to override this
mProducer->setMaxDequeuedBufferCount(2);
-#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
- mBufferReleaseThread.emplace(sp<BLASTBufferQueue>::fromExisting(this));
-#endif
}
void BLASTBufferQueue::update(const sp<SurfaceControl>& surface, uint32_t width, uint32_t height,
@@ -297,11 +293,16 @@
mSurfaceControl = surface;
SurfaceComposerClient::Transaction t;
if (surfaceControlChanged) {
+#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
+ // SELinux policy may prevent this process from sending the BufferReleaseChannel's file
+ // descriptor to SurfaceFlinger, causing the entire transaction to be dropped. This
+ // transaction is applied separately to ensure we don't lose the other updates.
+ t.setApplyToken(mApplyToken)
+ .setBufferReleaseChannel(mSurfaceControl, mBufferReleaseProducer)
+ .apply(false /* synchronous */, true /* oneWay */);
+#endif
t.setFlags(mSurfaceControl, layer_state_t::eEnableBackpressure,
layer_state_t::eEnableBackpressure);
-#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
- t.setBufferReleaseChannel(mSurfaceControl, mBufferReleaseProducer);
-#endif
applyTransaction = true;
}
mTransformHint = mSurfaceControl->getTransformHint();
@@ -325,7 +326,7 @@
}
if (applyTransaction) {
// All transactions on our apply token are one-way. See comment on mAppliedLastTransaction
- t.setApplyToken(mApplyToken).apply(false, true);
+ t.setApplyToken(mApplyToken).apply(false /* synchronous */, true /* oneWay */);
}
}
@@ -419,7 +420,6 @@
stat.latchTime,
stat.frameEventStats.dequeueReadyTime);
}
-#if !COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
auto currFrameNumber = stat.frameEventStats.frameNumber;
std::vector<ReleaseCallbackId> staleReleases;
for (const auto& [key, value]: mSubmitted) {
@@ -435,7 +435,6 @@
stat.currentMaxAcquiredBufferCount,
true /* fakeRelease */);
}
-#endif
} else {
BQA_LOGE("Failed to find matching SurfaceControl in transactionCallback");
}
@@ -469,6 +468,9 @@
return;
}
bbq->releaseBufferCallback(id, releaseFence, currentMaxAcquiredBufferCount);
+#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
+ bbq->drainBufferReleaseConsumer();
+#endif
};
}
@@ -535,8 +537,6 @@
const sp<Fence>& releaseFence) {
auto it = mSubmitted.find(callbackId);
if (it == mSubmitted.end()) {
- BQA_LOGE("ERROR: releaseBufferCallback without corresponding submitted buffer %s",
- callbackId.to_string().c_str());
return;
}
mNumAcquired--;
@@ -646,12 +646,7 @@
bufferItem.mGraphicBuffer->getHeight(), bufferItem.mTransform,
bufferItem.mScalingMode, crop);
-#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
- ReleaseBufferCallback releaseBufferCallback =
- applyTransaction ? nullptr : makeReleaseBufferCallbackThunk();
-#else
auto releaseBufferCallback = makeReleaseBufferCallbackThunk();
-#endif
sp<Fence> fence = bufferItem.mFence ? new Fence(bufferItem.mFence->dup()) : Fence::NO_FENCE;
nsecs_t dequeueTime = -1;
@@ -1230,12 +1225,7 @@
// we want to ignore it. This must be done before unlocking the BufferQueue lock to ensure
// we don't miss an interrupt.
bbq->mBufferReleaseReader->clearInterrupts();
- bbq->mThreadsBlockingOnDequeue++;
- bufferQueueLock.unlock();
- Deferred cleanup{[&]() {
- bufferQueueLock.lock();
- bbq->mThreadsBlockingOnDequeue--;
- }};
+ UnlockGuard unlockGuard{bufferQueueLock};
ATRACE_FORMAT("waiting for free buffer");
ReleaseCallbackId id;
@@ -1345,6 +1335,21 @@
#if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(BUFFER_RELEASE_CHANNEL)
+void BLASTBufferQueue::drainBufferReleaseConsumer() {
+ ATRACE_CALL();
+ while (true) {
+ ReleaseCallbackId id;
+ sp<Fence> fence;
+ uint32_t maxAcquiredBufferCount;
+ status_t status =
+ mBufferReleaseConsumer->readReleaseFence(id, fence, maxAcquiredBufferCount);
+ if (status != OK) {
+ return;
+ }
+ releaseBufferCallback(id, fence, maxAcquiredBufferCount);
+ }
+}
+
BLASTBufferQueue::BufferReleaseReader::BufferReleaseReader(BLASTBufferQueue& bbq) : mBbq{bbq} {
mEpollFd = android::base::unique_fd{epoll_create1(EPOLL_CLOEXEC)};
LOG_ALWAYS_FATAL_IF(!mEpollFd.ok(),
@@ -1438,95 +1443,6 @@
}
}
-BLASTBufferQueue::BufferReleaseThread::BufferReleaseThread(const sp<BLASTBufferQueue>& bbq) {
- android::base::unique_fd epollFd{epoll_create1(EPOLL_CLOEXEC)};
- LOG_ALWAYS_FATAL_IF(!epollFd.ok(),
- "Failed to create buffer release background thread epoll file descriptor. "
- "errno=%d message='%s'",
- errno, strerror(errno));
-
- epoll_event registerEndpointFd{};
- registerEndpointFd.events = EPOLLIN;
- registerEndpointFd.data.fd = bbq->mBufferReleaseConsumer->getFd();
- status_t status = epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, bbq->mBufferReleaseConsumer->getFd(),
- ®isterEndpointFd);
- LOG_ALWAYS_FATAL_IF(status == -1,
- "Failed to register background thread buffer release consumer file "
- "descriptor with epoll. errno=%d message='%s'",
- errno, strerror(errno));
-
- // EventFd is used to break the background thread's loop.
- android::base::unique_fd eventFd{eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK)};
- LOG_ALWAYS_FATAL_IF(!eventFd.ok(),
- "Failed to create background thread buffer release event file descriptor. "
- "errno=%d message='%s'",
- errno, strerror(errno));
-
- epoll_event registerEventFd{};
- registerEventFd.events = EPOLLIN;
- registerEventFd.data.fd = eventFd.get();
- status = epoll_ctl(epollFd.get(), EPOLL_CTL_ADD, eventFd.get(), ®isterEventFd);
- LOG_ALWAYS_FATAL_IF(status == -1,
- "Failed to register background thread event file descriptor with epoll. "
- "errno=%d message='%s'",
- errno, strerror(errno));
-
- mEventFd = eventFd.get();
-
- std::thread([epollFd = std::move(epollFd), eventFd = std::move(eventFd),
- weakBbq = wp<BLASTBufferQueue>(bbq)]() {
- pthread_setname_np(pthread_self(), "BufferReleaseThread");
- while (true) {
- epoll_event event{};
- int eventCount;
- do {
- eventCount = epoll_wait(epollFd.get(), &event, 1 /*maxevents*/, -1 /*timeout*/);
- } while (eventCount == -1 && errno != EINTR);
-
- if (eventCount == -1) {
- ALOGE("epoll_wait error while waiting for buffer release in background thread. "
- "errno=%d message='%s'",
- errno, strerror(errno));
- continue;
- }
-
- // EventFd is used to join this thread.
- if (event.data.fd == eventFd.get()) {
- return;
- }
-
- sp<BLASTBufferQueue> bbq = weakBbq.promote();
- if (!bbq) {
- return;
- }
-
- // If there are threads blocking on dequeue, give those threads priority for handling
- // the release.
- if (bbq->mThreadsBlockingOnDequeue > 0) {
- std::this_thread::sleep_for(0ms);
- continue;
- }
-
- ReleaseCallbackId id;
- sp<Fence> fence;
- uint32_t maxAcquiredBufferCount;
- status_t status = bbq->mBufferReleaseConsumer->readReleaseFence(id, fence,
- maxAcquiredBufferCount);
- if (status != OK) {
- ALOGE("failed to read from buffer release consumer in background thread. errno=%d "
- "message='%s'",
- errno, strerror(errno));
- continue;
- }
- bbq->releaseBufferCallback(id, fence, maxAcquiredBufferCount);
- }
- }).detach();
-}
-
-BLASTBufferQueue::BufferReleaseThread::~BufferReleaseThread() {
- eventfd_write(mEventFd, 1);
-}
-
#endif
} // namespace android