Let producer gain posted buffer if no released buffer exist. (f09f63f7) · Commits · e / os / android_frameworks_native-old

libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp

+109 −61

Original line number	Diff line number	Diff line
		@@ -69,7 +69,7 @@ void BufferHubQueue::Initialize() {
		.data = {.u64 = Stuff(-1, BufferHubQueue::kEpollQueueEventIndex)}};
		ret = epoll_fd_.Control(EPOLL_CTL_ADD, event_fd(), &event);
		if (ret < 0) {
		ALOGE("BufferHubQueue::Initialize: Failed to add event fd to epoll set: %s",
		ALOGE("%s: Failed to add event fd to epoll set: %s", __FUNCTION__,
		strerror(-ret));
		}
		}
		@@ -77,7 +77,7 @@ void BufferHubQueue::Initialize() {
		Status<void> BufferHubQueue::ImportQueue() {
		auto status = InvokeRemoteMethod<BufferHubRPC::GetQueueInfo>();
		if (!status) {
		ALOGE("BufferHubQueue::ImportQueue: Failed to import queue: %s",
		ALOGE("%s: Failed to import queue: %s", __FUNCTION__,
		status.GetErrorMessage().c_str());
		return ErrorStatus(status.error());
		} else {
		@@ -136,9 +136,7 @@ BufferHubQueue::CreateConsumerQueueParcelable(bool silent) {
		consumer_queue->GetChannel()->TakeChannelParcelable());

		if (!queue_parcelable.IsValid()) {
		ALOGE(
		"BufferHubQueue::CreateConsumerQueueParcelable: Failed to create "
		"consumer queue parcelable.");
		ALOGE("%s: Failed to create consumer queue parcelable.", __FUNCTION__);
		return ErrorStatus(EINVAL);
		}

		@@ -169,8 +167,7 @@ bool BufferHubQueue::WaitForBuffers(int timeout) {
		}

		if (ret < 0 && ret != -EINTR) {
		ALOGE("BufferHubQueue::WaitForBuffers: Failed to wait for buffers: %s",
		strerror(-ret));
		ALOGE("%s: Failed to wait for buffers: %s", __FUNCTION__, strerror(-ret));
		return false;
		}

		@@ -264,14 +261,14 @@ Status<void> BufferHubQueue::HandleQueueEvent(int poll_event) {
		// wait will be tried again to acquire the newly imported buffer.
		auto buffer_status = OnBufferAllocated();
		if (!buffer_status) {
		ALOGE("BufferHubQueue::HandleQueueEvent: Failed to import buffer: %s",
		ALOGE("%s: Failed to import buffer: %s", __FUNCTION__,
		buffer_status.GetErrorMessage().c_str());
		}
		} else if (events & EPOLLHUP) {
		ALOGD_IF(TRACE, "BufferHubQueue::HandleQueueEvent: hang up event!");
		ALOGD_IF(TRACE, "%s: hang up event!", __FUNCTION__);
		hung_up_ = true;
		} else {
		ALOGW("BufferHubQueue::HandleQueueEvent: Unknown epoll events=%x", events);
		ALOGW("%s: Unknown epoll events=%x", __FUNCTION__, events);
		}

		return {};
		@@ -279,12 +276,11 @@ Status<void> BufferHubQueue::HandleQueueEvent(int poll_event) {

		Status<void> BufferHubQueue::AddBuffer(
		const std::shared_ptr<BufferHubBase>& buffer, size_t slot) {
		ALOGD_IF(TRACE, "BufferHubQueue::AddBuffer: buffer_id=%d slot=%zu",
		buffer->id(), slot);
		ALOGD_IF(TRACE, "%s: buffer_id=%d slot=%zu", __FUNCTION__, buffer->id(),
		slot);

		if (is_full()) {
		ALOGE("BufferHubQueue::AddBuffer queue is at maximum capacity: %zu",
		capacity_);
		ALOGE("%s: queue is at maximum capacity: %zu", __FUNCTION__, capacity_);
		return ErrorStatus(E2BIG);
		}

		@@ -303,7 +299,7 @@ Status<void> BufferHubQueue::AddBuffer(
		const int ret =
		epoll_fd_.Control(EPOLL_CTL_ADD, event_source.event_fd, &event);
		if (ret < 0) {
		ALOGE("BufferHubQueue::AddBuffer: Failed to add buffer to epoll set: %s",
		ALOGE("%s: Failed to add buffer to epoll set: %s", __FUNCTION__,
		strerror(-ret));
		return ErrorStatus(-ret);
		}
		@@ -315,16 +311,14 @@ Status<void> BufferHubQueue::AddBuffer(
		}

		Status<void> BufferHubQueue::RemoveBuffer(size_t slot) {
		ALOGD_IF(TRACE, "BufferHubQueue::RemoveBuffer: slot=%zu", slot);
		ALOGD_IF(TRACE, "%s: slot=%zu", __FUNCTION__, slot);

		if (buffers_[slot]) {
		for (const auto& event_source : buffers_[slot]->GetEventSources()) {
		const int ret =
		epoll_fd_.Control(EPOLL_CTL_DEL, event_source.event_fd, nullptr);
		if (ret < 0) {
		ALOGE(
		"BufferHubQueue::RemoveBuffer: Failed to remove buffer from epoll "
		"set: %s",
		ALOGE("%s: Failed to remove buffer from epoll set: %s", __FUNCTION__,
		strerror(-ret));
		return ErrorStatus(-ret);
		}
		@@ -345,23 +339,31 @@ Status<void> BufferHubQueue::Enqueue(Entry entry) {
		if (!is_full()) {
		available_buffers_.push(std::move(entry));

		// Find and remove the enqueued buffer from unavailable_buffers_slot if
		// exist.
		auto enqueued_buffer_iter = std::find_if(
		unavailable_buffers_slot_.begin(), unavailable_buffers_slot_.end(),
		[&entry](size_t slot) -> bool { return slot == entry.slot; });
		if (enqueued_buffer_iter != unavailable_buffers_slot_.end()) {
		unavailable_buffers_slot_.erase(enqueued_buffer_iter);
		}

		// Trigger OnBufferAvailable callback if registered.
		if (on_buffer_available_)
		on_buffer_available_();

		return {};
		} else {
		ALOGE("BufferHubQueue::Enqueue: Buffer queue is full!");
		ALOGE("%s: Buffer queue is full!", __FUNCTION__);
		return ErrorStatus(E2BIG);
		}
		}

		Status<std::shared_ptr<BufferHubBase>> BufferHubQueue::Dequeue(int timeout,
		size_t* slot) {
		ALOGD_IF(TRACE, "BufferHubQueue::Dequeue: count=%zu, timeout=%d", count(),
		timeout);
		ALOGD_IF(TRACE, "%s: count=%zu, timeout=%d", __FUNCTION__, count(), timeout);

		PDX_TRACE_FORMAT("BufferHubQueue::Dequeue\|count=%zu\|", count());
		PDX_TRACE_FORMAT("%s\|count=%zu\|", __FUNCTION__, count());

		if (count() == 0) {
		if (!WaitForBuffers(timeout))
		@@ -376,6 +378,7 @@ Status<std::shared_ptr<BufferHubBase>> BufferHubQueue::Dequeue(int timeout,
		*slot = entry.slot;

		available_buffers_.pop();
		unavailable_buffers_slot_.push_back(*slot);

		return {std::move(buffer)};
		}
		@@ -564,7 +567,7 @@ Status<void> ProducerQueue::RemoveBuffer(size_t slot) {
		auto status =
		InvokeRemoteMethod<BufferHubRPC::ProducerQueueRemoveBuffer>(slot);
		if (!status) {
		ALOGE("ProducerQueue::RemoveBuffer: Failed to remove producer buffer: %s",
		ALOGE("%s: Failed to remove producer buffer: %s", __FUNCTION__,
		status.GetErrorMessage().c_str());
		return status.error_status();
		}
		@@ -580,31 +583,81 @@ Status<std::shared_ptr<BufferProducer>> ProducerQueue::Dequeue(

		pdx::Status<std::shared_ptr<BufferProducer>> ProducerQueue::Dequeue(
		int timeout, size_t* slot, DvrNativeBufferMetadata* out_meta,
		pdx::LocalHandle* release_fence) {
		pdx::LocalHandle* release_fence, bool gain_posted_buffer) {
		ATRACE_NAME("ProducerQueue::Dequeue");
		if (slot == nullptr \|\| out_meta == nullptr \|\| release_fence == nullptr) {
		ALOGE("ProducerQueue::Dequeue: Invalid parameter.");
		ALOGE("%s: Invalid parameter.", __FUNCTION__);
		return ErrorStatus(EINVAL);
		}

		auto status = BufferHubQueue::Dequeue(timeout, slot);
		if (!status)
		return status.error_status();

		auto buffer = std::static_pointer_cast<BufferProducer>(status.take());
		const int ret = buffer->GainAsync(out_meta, release_fence);
		std::shared_ptr<BufferProducer> buffer;
		Status<std::shared_ptr<BufferHubBase>> dequeue_status =
		BufferHubQueue::Dequeue(timeout, slot);
		if (dequeue_status.ok()) {
		buffer = std::static_pointer_cast<BufferProducer>(dequeue_status.take());
		} else {
		if (gain_posted_buffer) {
		Status<std::shared_ptr<BufferProducer>> dequeue_unacquired_status =
		ProducerQueue::DequeueUnacquiredBuffer(slot);
		if (!dequeue_unacquired_status.ok()) {
		ALOGE("%s: DequeueUnacquiredBuffer returned error: %d", __FUNCTION__,
		dequeue_unacquired_status.error());
		return dequeue_unacquired_status.error_status();
		}
		buffer = dequeue_unacquired_status.take();
		} else {
		return dequeue_status.error_status();
		}
		}
		const int ret =
		buffer->GainAsync(out_meta, release_fence, gain_posted_buffer);
		if (ret < 0 && ret != -EALREADY)
		return ErrorStatus(-ret);

		return {std::move(buffer)};
		}

		Status<std::shared_ptr<BufferProducer>> ProducerQueue::DequeueUnacquiredBuffer(
		size_t* slot) {
		if (unavailable_buffers_slot_.size() < 1) {
		ALOGE(
		"%s: Failed to dequeue un-acquired buffer. All buffer(s) are in "
		"acquired state if exist.",
		__FUNCTION__);
		return ErrorStatus(ENOMEM);
		}

		// Find the first buffer that is not in acquired state from
		// unavailable_buffers_slot_.
		for (auto iter = unavailable_buffers_slot_.begin();
		iter != unavailable_buffers_slot_.end(); iter++) {
		std::shared_ptr<BufferProducer> buffer = ProducerQueue::GetBuffer(*iter);
		if (buffer == nullptr) {
		ALOGE("%s failed. Buffer slot %d is null.", __FUNCTION__,
		static_cast<int>(*slot));
		return ErrorStatus(EIO);
		}
		if (!BufferHubDefs::IsBufferAcquired(buffer->buffer_state())) {
		slot = iter;
		unavailable_buffers_slot_.erase(iter);
		unavailable_buffers_slot_.push_back(*slot);
		ALOGD("%s: Producer queue dequeue unacquired buffer in slot %d",
		__FUNCTION__, static_cast<int>(*slot));
		return {std::move(buffer)};
		}
		}
		ALOGE(
		"%s: Failed to dequeue un-acquired buffer. No un-acquired buffer exist.",
		__FUNCTION__);
		return ErrorStatus(EBUSY);
		}

		pdx::Status<ProducerQueueParcelable> ProducerQueue::TakeAsParcelable() {
		if (capacity() != 0) {
		ALOGE(
		"ProducerQueue::TakeAsParcelable: producer queue can only be taken out"
		" as a parcelable when empty. Current queue capacity: %zu",
		capacity());
		"%s: producer queue can only be taken out as a parcelable when empty. "
		"Current queue capacity: %zu",
		__FUNCTION__, capacity());
		return ErrorStatus(EINVAL);
		}

		@@ -628,17 +681,16 @@ ConsumerQueue::ConsumerQueue(LocalChannelHandle handle)
		: BufferHubQueue(std::move(handle)) {
		auto status = ImportQueue();
		if (!status) {
		ALOGE("ConsumerQueue::ConsumerQueue: Failed to import queue: %s",
		ALOGE("%s: Failed to import queue: %s", __FUNCTION__,
		status.GetErrorMessage().c_str());
		Close(-status.error());
		}

		auto import_status = ImportBuffers();
		if (import_status) {
		ALOGI("ConsumerQueue::ConsumerQueue: Imported %zu buffers.",
		import_status.get());
		ALOGI("%s: Imported %zu buffers.", __FUNCTION__, import_status.get());
		} else {
		ALOGE("ConsumerQueue::ConsumerQueue: Failed to import buffers: %s",
		ALOGE("%s: Failed to import buffers: %s", __FUNCTION__,
		import_status.GetErrorMessage().c_str());
		}
		}
		@@ -647,13 +699,10 @@ Status<size_t> ConsumerQueue::ImportBuffers() {
		auto status = InvokeRemoteMethod<BufferHubRPC::ConsumerQueueImportBuffers>();
		if (!status) {
		if (status.error() == EBADR) {
		ALOGI(
		"ConsumerQueue::ImportBuffers: Queue is silent, no buffers "
		"imported.");
		ALOGI("%s: Queue is silent, no buffers imported.", __FUNCTION__);
		return {0};
		} else {
		ALOGE(
		"ConsumerQueue::ImportBuffers: Failed to import consumer buffer: %s",
		ALOGE("%s: Failed to import consumer buffer: %s", __FUNCTION__,
		status.GetErrorMessage().c_str());
		return status.error_status();
		}
		@@ -665,13 +714,13 @@ Status<size_t> ConsumerQueue::ImportBuffers() {

		auto buffer_handle_slots = status.take();
		for (auto& buffer_handle_slot : buffer_handle_slots) {
		ALOGD_IF(TRACE, "ConsumerQueue::ImportBuffers: buffer_handle=%d",
		ALOGD_IF(TRACE, ": buffer_handle=%d", __FUNCTION__,
		buffer_handle_slot.first.value());

		std::unique_ptr<BufferConsumer> buffer_consumer =
		BufferConsumer::Import(std::move(buffer_handle_slot.first));
		if (!buffer_consumer) {
		ALOGE("ConsumerQueue::ImportBuffers: Failed to import buffer: slot=%zu",
		ALOGE("%s: Failed to import buffer: slot=%zu", __FUNCTION__,
		buffer_handle_slot.second);
		last_error = ErrorStatus(EPIPE);
		continue;
		@@ -680,7 +729,7 @@ Status<size_t> ConsumerQueue::ImportBuffers() {
		auto add_status =
		AddBuffer(std::move(buffer_consumer), buffer_handle_slot.second);
		if (!add_status) {
		ALOGE("ConsumerQueue::ImportBuffers: Failed to add buffer: %s",
		ALOGE("%s: Failed to add buffer: %s", __FUNCTION__,
		add_status.GetErrorMessage().c_str());
		last_error = add_status;
		} else {
		@@ -696,8 +745,8 @@ Status<size_t> ConsumerQueue::ImportBuffers() {

		Status<void> ConsumerQueue::AddBuffer(
		const std::shared_ptr<BufferConsumer>& buffer, size_t slot) {
		ALOGD_IF(TRACE, "ConsumerQueue::AddBuffer: queue_id=%d buffer_id=%d slot=%zu",
		id(), buffer->id(), slot);
		ALOGD_IF(TRACE, "%s: queue_id=%d buffer_id=%d slot=%zu", __FUNCTION__, id(),
		buffer->id(), slot);
		return BufferHubQueue::AddBuffer(buffer, slot);
		}

		@@ -706,9 +755,9 @@ Status<std::shared_ptr<BufferConsumer>> ConsumerQueue::Dequeue(
		LocalHandle* acquire_fence) {
		if (user_metadata_size != user_metadata_size_) {
		ALOGE(
		"ConsumerQueue::Dequeue: Metadata size (%zu) for the dequeuing buffer "
		"does not match metadata size (%zu) for the queue.",
		user_metadata_size, user_metadata_size_);
		"%s: Metadata size (%zu) for the dequeuing buffer does not match "
		"metadata size (%zu) for the queue.",
		__FUNCTION__, user_metadata_size, user_metadata_size_);
		return ErrorStatus(EINVAL);
		}

		@@ -723,7 +772,7 @@ Status<std::shared_ptr<BufferConsumer>> ConsumerQueue::Dequeue(
		if (metadata_src) {
		memcpy(meta, metadata_src, user_metadata_size);
		} else {
		ALOGW("ConsumerQueue::Dequeue: no user-defined metadata.");
		ALOGW("%s: no user-defined metadata.", __FUNCTION__);
		}
		}

		@@ -735,7 +784,7 @@ Status<std::shared_ptr<BufferConsumer>> ConsumerQueue::Dequeue(
		pdx::LocalHandle* acquire_fence) {
		ATRACE_NAME("ConsumerQueue::Dequeue");
		if (slot == nullptr \|\| out_meta == nullptr \|\| acquire_fence == nullptr) {
		ALOGE("ConsumerQueue::Dequeue: Invalid parameter.");
		ALOGE("%s: Invalid parameter.", __FUNCTION__);
		return ErrorStatus(EINVAL);
		}

		@@ -752,19 +801,18 @@ Status<std::shared_ptr<BufferConsumer>> ConsumerQueue::Dequeue(
		}

		Status<void> ConsumerQueue::OnBufferAllocated() {
		ALOGD_IF(TRACE, "ConsumerQueue::OnBufferAllocated: queue_id=%d", id());
		ALOGD_IF(TRACE, "%s: queue_id=%d", __FUNCTION__, id());

		auto status = ImportBuffers();
		if (!status) {
		ALOGE("ConsumerQueue::OnBufferAllocated: Failed to import buffers: %s",
		ALOGE("%s: Failed to import buffers: %s", __FUNCTION__,
		status.GetErrorMessage().c_str());
		return ErrorStatus(status.error());
		} else if (status.get() == 0) {
		ALOGW("ConsumerQueue::OnBufferAllocated: No new buffers allocated!");
		ALOGW("%s: No new buffers allocated!", __FUNCTION__);
		return ErrorStatus(ENOBUFS);
		} else {
		ALOGD_IF(TRACE,
		"ConsumerQueue::OnBufferAllocated: Imported %zu consumer buffers.",
		ALOGD_IF(TRACE, "%s: Imported %zu consumer buffers.", __FUNCTION__,
		status.get());
		return {};
		}

libs/vr/libbufferhubqueue/include/private/dvr/buffer_hub_queue_client.h

+40 −7

Original line number	Diff line number	Diff line
		@@ -57,10 +57,10 @@ class BufferHubQueue : public pdx::Client {
		uint32_t default_width() const { return default_width_; }

		// Returns the default buffer height of this buffer queue.
		uint32_t default_height() const { return static_cast<uint32_t>(default_height_); }
		uint32_t default_height() const { return default_height_; }

		// Returns the default buffer format of this buffer queue.
		uint32_t default_format() const { return static_cast<uint32_t>(default_format_); }
		uint32_t default_format() const { return default_format_; }

		// Creates a new consumer in handle form for immediate transport over RPC.
		pdx::Status<pdx::LocalChannelHandle> CreateConsumerQueueHandle(
		@@ -208,6 +208,14 @@ class BufferHubQueue : public pdx::Client {
		// Size of the metadata that buffers in this queue cary.
		size_t user_metadata_size_{0};

		// Buffers and related data that are available for dequeue.
		std::priority_queue<Entry, std::vector<Entry>, EntryComparator>
		available_buffers_;

		// Slot of the buffers that are not available for normal dequeue. For example,
		// the slot of posted or acquired buffers in the perspective of a producer.
		std::vector<size_t> unavailable_buffers_slot_;

		private:
		void Initialize();

		@@ -252,10 +260,6 @@ class BufferHubQueue : public pdx::Client {
		// queue regardless of its queue position or presence in the ring buffer.
		std::array<std::shared_ptr<BufferHubBase>, kMaxQueueCapacity> buffers_;

		// Buffers and related data that are available for dequeue.
		std::priority_queue<Entry, std::vector<Entry>, EntryComparator>
		available_buffers_;

		// Keeps track with how many buffers have been added into the queue.
		size_t capacity_{0};

		@@ -349,11 +353,30 @@ class ProducerQueue : public pdx::ClientBase<ProducerQueue, BufferHubQueue> {
		// Dequeue a producer buffer to write. The returned buffer in \|Gain\|'ed mode,
		// and caller should call Post() once it's done writing to release the buffer
		// to the consumer side.
		// @return a buffer in gained state, which was originally in released state.
		pdx::Status<std::shared_ptr<BufferProducer>> Dequeue(
		int timeout, size_t* slot, pdx::LocalHandle* release_fence);

		// Dequeue a producer buffer to write. The returned buffer in \|Gain\|'ed mode,
		// and caller should call Post() once it's done writing to release the buffer
		// to the consumer side.
		//
		// @param timeout to dequeue a buffer.
		// @param slot is the slot of the output BufferProducer.
		// @param release_fence for gaining a buffer.
		// @param out_meta metadata of the output buffer.
		// @param gain_posted_buffer whether to gain posted buffer if no released
		// buffer is available to gain.
		// @return a buffer in gained state, which was originally in released state if
		// gain_posted_buffer is false, or in posted/released state if
		// gain_posted_buffer is true.
		// TODO(b/112007999): gain_posted_buffer true is only used to prevent
		// libdvrtracking from starving when there are non-responding clients. This
		// gain_posted_buffer param can be removed once libdvrtracking start to use
		// the new AHardwareBuffer API.
		pdx::Status<std::shared_ptr<BufferProducer>> Dequeue(
		int timeout, size_t* slot, DvrNativeBufferMetadata* out_meta,
		pdx::LocalHandle* release_fence);
		pdx::LocalHandle* release_fence, bool gain_posted_buffer = false);

		// Enqueues a producer buffer in the queue.
		pdx::Status<void> Enqueue(const std::shared_ptr<BufferProducer>& buffer,
		@@ -374,6 +397,16 @@ class ProducerQueue : public pdx::ClientBase<ProducerQueue, BufferHubQueue> {
		// arguments as the constructors.
		explicit ProducerQueue(pdx::LocalChannelHandle handle);
		ProducerQueue(const ProducerQueueConfig& config, const UsagePolicy& usage);

		// Dequeue a producer buffer to write. The returned buffer in \|Gain\|'ed mode,
		// and caller should call Post() once it's done writing to release the buffer
		// to the consumer side.
		//
		// @param slot the slot of the returned buffer.
		// @return a buffer in gained state, which was originally in posted state or
		// released state.
		pdx::Status<std::shared_ptr<BufferProducer>> DequeueUnacquiredBuffer(
		size_t* slot);
		};

		class ConsumerQueue : public BufferHubQueue {

libs/vr/libbufferhubqueue/tests/buffer_hub_queue-test.cpp

+144 −2

Original line number	Diff line number	Diff line
		#include <base/logging.h>
		#include <binder/Parcel.h>
		#include <dvr/dvr_api.h>
		#include <private/dvr/buffer_hub_client.h>
		#include <private/dvr/buffer_hub_queue_client.h>

		@@ -122,6 +123,147 @@ TEST_F(BufferHubQueueTest, TestDequeue) {
		}
		}

		TEST_F(BufferHubQueueTest,
		TestDequeuePostedBufferIfNoAvailableReleasedBuffer_withBufferConsumer) {
		ASSERT_TRUE(CreateQueues(config_builder_.Build(), UsagePolicy{}));

		// Allocate 3 buffers to use.
		const size_t test_queue_capacity = 3;
		for (int64_t i = 0; i < test_queue_capacity; i++) {
		AllocateBuffer();
		}
		EXPECT_EQ(producer_queue_->capacity(), test_queue_capacity);

		size_t producer_slot, consumer_slot;
		LocalHandle fence;
		DvrNativeBufferMetadata mi, mo;

		// Producer posts 2 buffers and remember their posted sequence.
		std::deque<size_t> posted_slots;
		for (int64_t i = 0; i < 2; i++) {
		auto p1_status =
		producer_queue_->Dequeue(kTimeoutMs, &producer_slot, &mo, &fence, true);
		EXPECT_TRUE(p1_status.ok());
		auto p1 = p1_status.take();
		ASSERT_NE(p1, nullptr);

		// Producer should not be gaining posted buffer when there are still
		// available buffers to gain.
		auto found_iter =
		std::find(posted_slots.begin(), posted_slots.end(), producer_slot);
		EXPECT_EQ(found_iter, posted_slots.end());
		posted_slots.push_back(producer_slot);

		// Producer posts the buffer.
		mi.index = i;
		EXPECT_EQ(0, p1->PostAsync(&mi, LocalHandle()));
		}

		// Consumer acquires one buffer.
		auto c1_status =
		consumer_queue_->Dequeue(kTimeoutMs, &consumer_slot, &mo, &fence);
		EXPECT_TRUE(c1_status.ok());
		auto c1 = c1_status.take();
		ASSERT_NE(c1, nullptr);
		// Consumer should get the oldest posted buffer. No checks here.
		// posted_slots[0] should be in acquired state now.
		EXPECT_EQ(mo.index, 0);
		// Consumer releases the buffer.
		EXPECT_EQ(c1->ReleaseAsync(&mi, LocalHandle()), 0);
		// posted_slots[0] should be in released state now.

		// Producer gain and post 2 buffers.
		for (int64_t i = 0; i < 2; i++) {
		auto p1_status =
		producer_queue_->Dequeue(kTimeoutMs, &producer_slot, &mo, &fence, true);
		EXPECT_TRUE(p1_status.ok());
		auto p1 = p1_status.take();
		ASSERT_NE(p1, nullptr);

		// The gained buffer should be the one in released state or the one haven't
		// been use.
		EXPECT_NE(posted_slots[1], producer_slot);

		mi.index = i + 2;
		EXPECT_EQ(0, p1->PostAsync(&mi, LocalHandle()));
		}

		// Producer gains a buffer.
		auto p1_status =
		producer_queue_->Dequeue(kTimeoutMs, &producer_slot, &mo, &fence, true);
		EXPECT_TRUE(p1_status.ok());
		auto p1 = p1_status.take();
		ASSERT_NE(p1, nullptr);

		// The gained buffer should be the oldest posted buffer.
		EXPECT_EQ(posted_slots[1], producer_slot);

		// Producer posts the buffer.
		mi.index = 4;
		EXPECT_EQ(0, p1->PostAsync(&mi, LocalHandle()));
		}

		TEST_F(BufferHubQueueTest,
		TestDequeuePostedBufferIfNoAvailableReleasedBuffer_noBufferConsumer) {
		ASSERT_TRUE(CreateQueues(config_builder_.Build(), UsagePolicy{}));

		// Allocate 4 buffers to use.
		const size_t test_queue_capacity = 4;
		for (int64_t i = 0; i < test_queue_capacity; i++) {
		AllocateBuffer();
		}
		EXPECT_EQ(producer_queue_->capacity(), test_queue_capacity);

		// Post all allowed buffers and remember their posted sequence.
		std::deque<size_t> posted_slots;
		for (int64_t i = 0; i < test_queue_capacity; i++) {
		size_t slot;
		LocalHandle fence;
		DvrNativeBufferMetadata mi, mo;

		// Producer gains a buffer.
		auto p1_status =
		producer_queue_->Dequeue(kTimeoutMs, &slot, &mo, &fence, true);
		EXPECT_TRUE(p1_status.ok());
		auto p1 = p1_status.take();
		ASSERT_NE(p1, nullptr);

		// Producer should not be gaining posted buffer when there are still
		// available buffers to gain.
		auto found_iter = std::find(posted_slots.begin(), posted_slots.end(), slot);
		EXPECT_EQ(found_iter, posted_slots.end());
		posted_slots.push_back(slot);

		// Producer posts the buffer.
		mi.index = i;
		EXPECT_EQ(p1->PostAsync(&mi, LocalHandle()), 0);
		}

		// Gain posted buffers in sequence.
		const int64_t nb_dequeue_all_times = 2;
		for (int j = 0; j < nb_dequeue_all_times; ++j) {
		for (int i = 0; i < test_queue_capacity; ++i) {
		size_t slot;
		LocalHandle fence;
		DvrNativeBufferMetadata mi, mo;

		// Producer gains a buffer.
		auto p1_status =
		producer_queue_->Dequeue(kTimeoutMs, &slot, &mo, &fence, true);
		EXPECT_TRUE(p1_status.ok());
		auto p1 = p1_status.take();
		ASSERT_NE(p1, nullptr);

		// The gained buffer should be the oldest posted buffer.
		EXPECT_EQ(posted_slots[i], slot);

		// Producer posts the buffer.
		mi.index = i + test_queue_capacity * (j + 1);
		EXPECT_EQ(p1->PostAsync(&mi, LocalHandle()), 0);
		}
		}
		}

		TEST_F(BufferHubQueueTest, TestProducerConsumer) {
		const size_t kBufferCount = 16;
		size_t slot;
		@@ -245,8 +387,8 @@ TEST_F(BufferHubQueueTest, TestRemoveBuffer) {

		for (size_t i = 0; i < kBufferCount; i++) {
		Entry* entry = &buffers[i];
		auto producer_status = producer_queue_->Dequeue(
		kTimeoutMs, &entry->slot, &mo, &entry->fence);
		auto producer_status =
		producer_queue_->Dequeue(kTimeoutMs, &entry->slot, &mo, &entry->fence);
		ASSERT_TRUE(producer_status.ok());
		entry->buffer = producer_status.take();
		ASSERT_NE(nullptr, entry->buffer);