ConsumerBase: free buffers outside the lock
This change makes ConsumerBase::onBuffersReleased hold a reference to all its
gralloc buffers until after the mutex is unlocked. This prevents slow
gralloc::free calls from causing lock contention with rendering threads.
Bug: 7675940
Change-Id: I0ec805d1b612afeeecfffec03f982371d27d93be
diff --git a/libs/gui/ConsumerBase.cpp b/libs/gui/ConsumerBase.cpp
index 624d7e0..cfc0293 100644
--- a/libs/gui/ConsumerBase.cpp
+++ b/libs/gui/ConsumerBase.cpp
@@ -109,21 +109,35 @@
}
void ConsumerBase::onBuffersReleased() {
- Mutex::Autolock lock(mMutex);
+ sp<GraphicBuffer> bufRefs[BufferQueue::NUM_BUFFER_SLOTS];
- CB_LOGV("onBuffersReleased");
+ { // Scope for the lock
+ Mutex::Autolock lock(mMutex);
- if (mAbandoned) {
- // Nothing to do if we're already abandoned.
- return;
+ CB_LOGV("onBuffersReleased");
+
+ if (mAbandoned) {
+ // Nothing to do if we're already abandoned.
+ return;
+ }
+
+ uint32_t mask = 0;
+ mBufferQueue->getReleasedBuffers(&mask);
+ for (int i = 0; i < BufferQueue::NUM_BUFFER_SLOTS; i++) {
+ if (mask & (1 << i)) {
+ // Grab a local reference to the buffers so that they don't
+ // get freed while the lock is held.
+ bufRefs[i] = mSlots[i].mGraphicBuffer;
+
+ freeBufferLocked(i);
+ }
+ }
}
- uint32_t mask = 0;
- mBufferQueue->getReleasedBuffers(&mask);
+ // Clear the local buffer references. This would happen automatically
+ // when the array gets dtor'd, but I'm doing it explicitly for clarity.
for (int i = 0; i < BufferQueue::NUM_BUFFER_SLOTS; i++) {
- if (mask & (1 << i)) {
- freeBufferLocked(i);
- }
+ bufRefs[i].clear();
}
}