BufferQueue consumers: Add discardFreeBuffer method
This method releases all free buffers owned by the buffer queue,
in order to save memory (at the cost of potential future
reallocation of buffers).
Bug: 28695173
Change-Id: I458d10373e639e3144faf673af2ba01aca36e65a
diff --git a/libs/gui/tests/BufferQueue_test.cpp b/libs/gui/tests/BufferQueue_test.cpp
index 210ce8c..8a9eeee 100644
--- a/libs/gui/tests/BufferQueue_test.cpp
+++ b/libs/gui/tests/BufferQueue_test.cpp
@@ -990,4 +990,81 @@
ASSERT_EQ(true, thirdSegment.usedThirdBuffer);
}
+TEST_F(BufferQueueTest, TestDiscardFreeBuffers) {
+ createBufferQueue();
+ sp<DummyConsumer> dc(new DummyConsumer);
+ ASSERT_EQ(OK, mConsumer->consumerConnect(dc, false));
+ IGraphicBufferProducer::QueueBufferOutput output;
+ ASSERT_EQ(OK, mProducer->connect(new DummyProducerListener,
+ NATIVE_WINDOW_API_CPU, false, &output));
+
+ int slot = BufferQueue::INVALID_BUFFER_SLOT;
+ sp<Fence> fence = Fence::NO_FENCE;
+ sp<GraphicBuffer> buffer = nullptr;
+ IGraphicBufferProducer::QueueBufferInput input(0ull, true,
+ HAL_DATASPACE_UNKNOWN, Rect::INVALID_RECT,
+ NATIVE_WINDOW_SCALING_MODE_FREEZE, 0, Fence::NO_FENCE);
+ BufferItem item{};
+
+ // Preallocate, dequeue, request, and cancel 4 buffers so we don't get
+ // BUFFER_NEEDS_REALLOCATION below
+ int slots[4] = {};
+ mProducer->setMaxDequeuedBufferCount(4);
+ for (size_t i = 0; i < 4; ++i) {
+ status_t result = mProducer->dequeueBuffer(&slots[i], &fence,
+ 0, 0, 0, 0);
+ ASSERT_EQ(IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION, result);
+ ASSERT_EQ(OK, mProducer->requestBuffer(slots[i], &buffer));
+ }
+ for (size_t i = 0; i < 4; ++i) {
+ ASSERT_EQ(OK, mProducer->cancelBuffer(slots[i], Fence::NO_FENCE));
+ }
+
+ // Get buffers in all states: dequeued, filled, acquired, free
+
+ // Fill 3 buffers
+ ASSERT_EQ(OK, mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0));
+ ASSERT_EQ(OK, mProducer->queueBuffer(slot, input, &output));
+ ASSERT_EQ(OK, mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0));
+ ASSERT_EQ(OK, mProducer->queueBuffer(slot, input, &output));
+ ASSERT_EQ(OK, mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0));
+ ASSERT_EQ(OK, mProducer->queueBuffer(slot, input, &output));
+ // Dequeue 1 buffer
+ ASSERT_EQ(OK, mProducer->dequeueBuffer(&slot, &fence, 0, 0, 0, 0));
+
+ // Acquire and free 1 buffer
+ ASSERT_EQ(OK, mConsumer->acquireBuffer(&item, 0));
+ ASSERT_EQ(OK, mConsumer->releaseBuffer(item.mSlot, item.mFrameNumber,
+ EGL_NO_DISPLAY, EGL_NO_SYNC_KHR, Fence::NO_FENCE));
+ // Acquire 1 buffer, leaving 1 filled buffer in queue
+ ASSERT_EQ(OK, mConsumer->acquireBuffer(&item, 0));
+
+ // Now discard the free buffers
+ ASSERT_EQ(OK, mConsumer->discardFreeBuffers());
+
+ // Check no free buffers in dump
+ String8 dumpString;
+ mConsumer->dump(dumpString, nullptr);
+
+ // Parse the dump to ensure that all buffer slots that are FREE also
+ // have a null GraphicBuffer
+ // Fragile - assumes the following format for the dump for a buffer entry:
+ // ":%p\][^:]*state=FREE" where %p is the buffer pointer in hex.
+ ssize_t idx = dumpString.find("state=FREE");
+ while (idx != -1) {
+ ssize_t bufferPtrIdx = idx - 1;
+ while (bufferPtrIdx > 0) {
+ if (dumpString[bufferPtrIdx] == ':') {
+ bufferPtrIdx++;
+ break;
+ }
+ bufferPtrIdx--;
+ }
+ ASSERT_GT(bufferPtrIdx, 0) << "Can't parse queue dump to validate";
+ ssize_t nullPtrIdx = dumpString.find("0x0]", bufferPtrIdx);
+ ASSERT_EQ(bufferPtrIdx, nullPtrIdx) << "Free buffer not discarded";
+ idx = dumpString.find("FREE", idx + 1);
+ }
+}
+
} // namespace android