Change the definition of buffer state and client state bits.
Please refer to go/bufferhub-buffer-state-redesign for more information.
In this change:
1. Every clients takes up two bits in the buffer_state.
One from the higher 32 bits, one from the lower 32 bits. For details:
go/bufferhub-buffer-state-redesign
2. Upon the creation of a new buffer, the buffer is in released state.
Previously, only producer creates buffer, and upon creation, the buffer
was in gained state. Now, producer needs to specifically gain the buffer
before trying to produce and post it.
3. If there is no other clients when a client post a buffer, the buffer
will actually be in released state instead of posted state. This is
because the posted buffer does not have readers and can be reused
immediately.
4. If a new client is added to the buffer when the buffer is in acquired
or posted state, the buffer state of the new client will be set to posted
state and able to acquire the same buffer content as posted.
In the next change:
variables of type std::atomic<uint64_t> in metadata header in shared memory
will be replaced by std::atomic<uint32_t>
Test: marlin-eng passing AHardwareBufferTest BufferHubBuffer_test
BufferHubMetadata_test buffer_hub_binder_service-test
buffer_hub_queue_producer-test dvr_api-test libgui_test
libsensor_test vrflinger_test buffer_hub-test
dvr_buffer_queue-test dvr_display-test buffer_hub_queue-test
Test: smartphone VR works on blueline-eng
Test: vega_xr passing AHardwareBufferTest BufferHubBuffer_test
BufferHubMetadata_test buffer_hub_queue_producer-test buffer_hub-test
buffer_hub_queue-test dvr_buffer_queue-test dvr_api-test
Cherrypicking this changelist to oc-dr1-daydream-dev branch requires
ag/5514563 to be merged at the same time to make Vega actually work.
Bug: 112007999
Change-Id: I86393818ad922a91c709fe22f8e99b0667d2e9ef
diff --git a/services/vr/bufferhubd/producer_channel.cpp b/services/vr/bufferhubd/producer_channel.cpp
index c6e8ea9..55034b3 100644
--- a/services/vr/bufferhubd/producer_channel.cpp
+++ b/services/vr/bufferhubd/producer_channel.cpp
@@ -255,16 +255,16 @@
// that release active_clients_bit_mask_ need to be visible here.
uint64_t current_active_clients_bit_mask =
active_clients_bit_mask_->load(std::memory_order_acquire);
- uint64_t client_state_mask = BufferHubDefs::FindNextAvailableClientStateMask(
- current_active_clients_bit_mask | orphaned_consumer_bit_mask_);
- if (client_state_mask == 0ULL) {
- ALOGE(
- "ProducerChannel::CreateConsumer: reached the maximum mumber of "
- "consumers per producer: 63.");
+ uint64_t consumer_state_mask =
+ BufferHubDefs::FindNextAvailableClientStateMask(
+ current_active_clients_bit_mask | orphaned_consumer_bit_mask_);
+ if (consumer_state_mask == 0ULL) {
+ ALOGE("%s: reached the maximum mumber of consumers per producer: 63.",
+ __FUNCTION__);
return ErrorStatus(E2BIG);
}
uint64_t updated_active_clients_bit_mask =
- current_active_clients_bit_mask | client_state_mask;
+ current_active_clients_bit_mask | consumer_state_mask;
// Set the updated value only if the current value stays the same as what was
// read before. If the comparison succeeds, update the value without
// reordering anything before or after this read-modify-write in the current
@@ -276,24 +276,24 @@
while (!active_clients_bit_mask_->compare_exchange_weak(
current_active_clients_bit_mask, updated_active_clients_bit_mask,
std::memory_order_acq_rel, std::memory_order_acquire)) {
- ALOGE("Current active clients bit mask is changed to %" PRIx64
+ ALOGE("%s: Current active clients bit mask is changed to %" PRIx64
", which was expected to be %" PRIx64
". Trying to generate a new client state mask to resolve race "
"condition.",
- updated_active_clients_bit_mask, current_active_clients_bit_mask);
- client_state_mask = BufferHubDefs::FindNextAvailableClientStateMask(
+ __FUNCTION__, updated_active_clients_bit_mask,
+ current_active_clients_bit_mask);
+ consumer_state_mask = BufferHubDefs::FindNextAvailableClientStateMask(
current_active_clients_bit_mask | orphaned_consumer_bit_mask_);
- if (client_state_mask == 0ULL) {
- ALOGE(
- "ProducerChannel::CreateConsumer: reached the maximum mumber of "
- "consumers per producer: 63.");
+ if (consumer_state_mask == 0ULL) {
+ ALOGE("%s: reached the maximum mumber of consumers per producer: %d.",
+ __FUNCTION__, (BufferHubDefs::kMaxNumberOfClients - 1));
return ErrorStatus(E2BIG);
}
updated_active_clients_bit_mask =
- current_active_clients_bit_mask | client_state_mask;
+ current_active_clients_bit_mask | consumer_state_mask;
}
- return {client_state_mask};
+ return {consumer_state_mask};
}
void ProducerChannel::RemoveConsumerClientMask(uint64_t consumer_state_mask) {
@@ -311,17 +311,15 @@
Status<RemoteChannelHandle> ProducerChannel::CreateConsumer(
Message& message, uint64_t consumer_state_mask) {
- ATRACE_NAME("ProducerChannel::CreateConsumer");
- ALOGD_IF(TRACE,
- "ProducerChannel::CreateConsumer: buffer_id=%d, producer_owns=%d",
+ ATRACE_NAME(__FUNCTION__);
+ ALOGD_IF(TRACE, "%s: buffer_id=%d, producer_owns=%d", __FUNCTION__,
buffer_id(), producer_owns_);
int channel_id;
auto status = message.PushChannel(0, nullptr, &channel_id);
if (!status) {
- ALOGE(
- "ProducerChannel::CreateConsumer: Failed to push consumer channel: %s",
- status.GetErrorMessage().c_str());
+ ALOGE("%s: Failed to push consumer channel: %s", __FUNCTION__,
+ status.GetErrorMessage().c_str());
RemoveConsumerClientMask(consumer_state_mask);
return ErrorStatus(ENOMEM);
}
@@ -331,24 +329,52 @@
shared_from_this());
const auto channel_status = service()->SetChannel(channel_id, consumer);
if (!channel_status) {
- ALOGE(
- "ProducerChannel::CreateConsumer: failed to set new consumer channel: "
- "%s",
- channel_status.GetErrorMessage().c_str());
+ ALOGE("%s: failed to set new consumer channel: %s.", __FUNCTION__,
+ channel_status.GetErrorMessage().c_str());
RemoveConsumerClientMask(consumer_state_mask);
return ErrorStatus(ENOMEM);
}
uint64_t current_buffer_state =
buffer_state_->load(std::memory_order_acquire);
- if (!producer_owns_ &&
- (BufferHubDefs::IsBufferPosted(current_buffer_state) ||
- BufferHubDefs::IsBufferAcquired(current_buffer_state))) {
- // Signal the new consumer when adding it to a posted producer.
- if (consumer->OnProducerPosted())
- pending_consumers_++;
+ if (BufferHubDefs::IsBufferReleased(current_buffer_state) ||
+ BufferHubDefs::AnyClientGained(current_buffer_state)) {
+ return {status.take()};
}
+ // Signal the new consumer when adding it to a posted producer.
+ bool update_buffer_state = true;
+ if (!BufferHubDefs::IsClientPosted(current_buffer_state,
+ consumer_state_mask)) {
+ uint64_t updated_buffer_state =
+ current_buffer_state ^
+ (consumer_state_mask & BufferHubDefs::kHighBitsMask);
+ while (!buffer_state_->compare_exchange_weak(
+ current_buffer_state, updated_buffer_state, std::memory_order_acq_rel,
+ std::memory_order_acquire)) {
+ ALOGI(
+ "%s: Failed to post to the new consumer. "
+ "Current buffer state was changed to %" PRIx64
+ " when trying to acquire the buffer and modify the buffer state to "
+ "%" PRIx64
+ ". About to try again if the buffer is still not gained nor fully "
+ "released.",
+ __FUNCTION__, current_buffer_state, updated_buffer_state);
+ if (BufferHubDefs::IsBufferReleased(current_buffer_state) ||
+ BufferHubDefs::AnyClientGained(current_buffer_state)) {
+ ALOGI("%s: buffer is gained or fully released, state=%" PRIx64 ".",
+ __FUNCTION__, current_buffer_state);
+ update_buffer_state = false;
+ break;
+ }
+ updated_buffer_state =
+ current_buffer_state ^
+ (consumer_state_mask & BufferHubDefs::kHighBitsMask);
+ }
+ }
+ if (update_buffer_state && consumer->OnProducerPosted())
+ pending_consumers_++;
+
return {status.take()};
}
@@ -422,7 +448,8 @@
if (producer_owns_) {
ALOGE("ProducerChanneL::OnGain: Already in gained state: channel=%d",
channel_id());
- return ErrorStatus(EALREADY);
+ // TODO(b/119331650): remove this if check if producer_owns_ is removed.
+ // return ErrorStatus(EALREADY);
}
// There are still pending consumers, return busy.
@@ -431,7 +458,10 @@
"ProducerChannel::OnGain: Producer (id=%d) is gaining a buffer that "
"still has %d pending consumer(s).",
buffer_id(), pending_consumers_);
- return ErrorStatus(EBUSY);
+ // TODO(b/77153033): add gain_posted_buffer to the impulse args, and
+ // return busy if the function does not allow gaining posted buffer.
+ // TODO(b/119331650): remove this if check if pending_consumers_ is removed.
+ // return ErrorStatus(EBUSY);
}
ClearAvailable();
@@ -449,10 +479,12 @@
buffer_id());
uint64_t buffer_state = buffer_state_->load(std::memory_order_acquire);
- if (!BufferHubDefs::IsBufferGained(buffer_state)) {
+ if (!BufferHubDefs::IsClientGained(
+ buffer_state, BufferHubDefs::kFirstClientStateMask)) {
// Can only detach a BufferProducer when it's in gained state.
ALOGW(
- "ProducerChannel::OnProducerDetach: The buffer (id=%d, state=0x%" PRIx64
+ "ProducerChannel::OnProducerDetach: The buffer (id=%d, state=%"
+ PRIx64
") is not in gained state.",
buffer_id(), buffer_state);
return {};
@@ -485,12 +517,11 @@
const auto channel_status =
service()->SetChannel(channel_id, std::move(channel));
if (!channel_status) {
- // Technically, this should never fail, as we just pushed the channel. Note
- // that LOG_FATAL will be stripped out in non-debug build.
+ // Technically, this should never fail, as we just pushed the channel.
+ // Note that LOG_FATAL will be stripped out in non-debug build.
LOG_FATAL(
- "ProducerChannel::OnProducerDetach: Failed to set new detached buffer "
- "channel: %s.",
- channel_status.GetErrorMessage().c_str());
+ "ProducerChannel::OnProducerDetach: Failed to set new detached "
+ "buffer channel: %s.", channel_status.GetErrorMessage().c_str());
}
return status;
@@ -505,8 +536,8 @@
return ErrorStatus(EBUSY);
}
- // Return a borrowed fd to avoid unnecessary duplication of the underlying fd.
- // Serialization just needs to read the handle.
+ // Return a borrowed fd to avoid unnecessary duplication of the underlying
+ // fd. Serialization just needs to read the handle.
return {std::move(post_fence_)};
}
@@ -539,28 +570,13 @@
}
DecrementPendingConsumers();
- if (pending_consumers_ == 0) {
- // Clear the producer bit atomically to transit into released state. This
- // has to done by BufferHub as it requries synchronization among all
- // consumers.
- BufferHubDefs::ModifyBufferState(buffer_state_,
- BufferHubDefs::kFirstClientBitMask, 0ULL);
- ALOGD_IF(TRACE,
- "ProducerChannel::OnConsumerRelease: releasing last consumer: "
- "buffer_id=%d state=%" PRIx64 ".",
- buffer_id(), buffer_state_->load(std::memory_order_acquire));
-
- if (orphaned_consumer_bit_mask_) {
- ALOGW(
- "ProducerChannel::OnConsumerRelease: orphaned buffer detected "
- "during the this acquire/release cycle: id=%d orphaned=0x%" PRIx64
- " queue_index=%" PRIu64 ".",
- buffer_id(), orphaned_consumer_bit_mask_,
- metadata_header_->queue_index);
- orphaned_consumer_bit_mask_ = 0;
- }
-
- SignalAvailable();
+ if (pending_consumers_ == 0 && orphaned_consumer_bit_mask_) {
+ ALOGW(
+ "%s: orphaned buffer detected during the this acquire/release cycle: "
+ "id=%d orphaned=0x%" PRIx64 " queue_index=%" PRIx64 ".",
+ __FUNCTION__, buffer_id(), orphaned_consumer_bit_mask_,
+ metadata_header_->queue_index);
+ orphaned_consumer_bit_mask_ = 0;
}
ALOGE_IF(
@@ -579,34 +595,43 @@
}
--pending_consumers_;
- ALOGD_IF(TRACE,
- "ProducerChannel::DecrementPendingConsumers: buffer_id=%d %d "
- "consumers left",
+ ALOGD_IF(TRACE, "%s: buffer_id=%d %d consumers left", __FUNCTION__,
buffer_id(), pending_consumers_);
+
+ if (pending_consumers_ == 0) {
+ ALOGD_IF(TRACE,
+ "%s: releasing last consumer: buffer_id=%d state=%" PRIx64 ".",
+ __FUNCTION__, buffer_id(),
+ buffer_state_->load(std::memory_order_acquire));
+ SignalAvailable();
+ }
}
-void ProducerChannel::OnConsumerOrphaned(ConsumerChannel* channel) {
+void ProducerChannel::OnConsumerOrphaned(const uint64_t& consumer_state_mask) {
// Ignore the orphaned consumer.
DecrementPendingConsumers();
- const uint64_t client_state_mask = channel->client_state_mask();
- ALOGE_IF(orphaned_consumer_bit_mask_ & client_state_mask,
- "ProducerChannel::OnConsumerOrphaned: Consumer "
- "(client_state_mask=%" PRIx64 ") is already orphaned.",
- client_state_mask);
- orphaned_consumer_bit_mask_ |= client_state_mask;
+ // Remember the ignored consumer so that newly added consumer won't be
+ // taking the same state mask as this orphaned consumer.
+ ALOGE_IF(orphaned_consumer_bit_mask_ & consumer_state_mask,
+ "%s: Consumer (consumer_state_mask=%" PRIx64
+ ") is already orphaned.",
+ __FUNCTION__, consumer_state_mask);
+ orphaned_consumer_bit_mask_ |= consumer_state_mask;
// Atomically clear the fence state bit as an orphaned consumer will never
- // signal a release fence. Also clear the buffer state as it won't be released
- // as well.
- fence_state_->fetch_and(~client_state_mask);
- BufferHubDefs::ModifyBufferState(buffer_state_, client_state_mask, 0ULL);
+ // signal a release fence.
+ fence_state_->fetch_and(~consumer_state_mask, std::memory_order_release);
+
+ // Atomically set the buffer state of this consumer to released state.
+ buffer_state_->fetch_and(~consumer_state_mask, std::memory_order_release);
ALOGW(
- "ProducerChannel::OnConsumerOrphaned: detected new orphaned consumer "
- "buffer_id=%d client_state_mask=%" PRIx64 " queue_index=%" PRIu64
+ "%s: detected new orphaned consumer buffer_id=%d "
+ "consumer_state_mask=%" PRIx64 " queue_index=%" PRIx64
" buffer_state=%" PRIx64 " fence_state=%" PRIx64 ".",
- buffer_id(), client_state_mask, metadata_header_->queue_index,
+ __FUNCTION__, buffer_id(), consumer_state_mask,
+ metadata_header_->queue_index,
buffer_state_->load(std::memory_order_acquire),
fence_state_->load(std::memory_order_acquire));
}
@@ -620,45 +645,64 @@
std::find(consumer_channels_.begin(), consumer_channels_.end(), channel));
// Restore the consumer state bit and make it visible in other threads that
// acquire the active_clients_bit_mask_.
- active_clients_bit_mask_->fetch_and(~channel->client_state_mask(),
- std::memory_order_release);
+ uint64_t consumer_state_mask = channel->client_state_mask();
+ uint64_t current_active_clients_bit_mask =
+ active_clients_bit_mask_->load(std::memory_order_acquire);
+ uint64_t updated_active_clients_bit_mask =
+ current_active_clients_bit_mask & (~consumer_state_mask);
+ while (!active_clients_bit_mask_->compare_exchange_weak(
+ current_active_clients_bit_mask, updated_active_clients_bit_mask,
+ std::memory_order_acq_rel, std::memory_order_acquire)) {
+ ALOGI(
+ "%s: Failed to remove consumer state mask. Current active clients bit "
+ "mask is changed to %" PRIu64
+ " when trying to acquire and modify it to %" PRIu64
+ ". About to try again.",
+ __FUNCTION__, current_active_clients_bit_mask,
+ updated_active_clients_bit_mask);
+ updated_active_clients_bit_mask =
+ current_active_clients_bit_mask & (~consumer_state_mask);
+ }
- const uint64_t buffer_state = buffer_state_->load(std::memory_order_acquire);
- if (BufferHubDefs::IsBufferPosted(buffer_state) ||
- BufferHubDefs::IsBufferAcquired(buffer_state)) {
+ const uint64_t current_buffer_state =
+ buffer_state_->load(std::memory_order_acquire);
+ if (BufferHubDefs::IsClientPosted(current_buffer_state,
+ consumer_state_mask) ||
+ BufferHubDefs::IsClientAcquired(current_buffer_state,
+ consumer_state_mask)) {
// The consumer client is being destoryed without releasing. This could
// happen in corner cases when the consumer crashes. Here we mark it
// orphaned before remove it from producer.
- OnConsumerOrphaned(channel);
+ OnConsumerOrphaned(consumer_state_mask);
+ return;
}
- if (BufferHubDefs::IsBufferReleased(buffer_state) ||
- BufferHubDefs::IsBufferGained(buffer_state)) {
+ if (BufferHubDefs::IsClientReleased(current_buffer_state,
+ consumer_state_mask) ||
+ BufferHubDefs::AnyClientGained(current_buffer_state)) {
// The consumer is being close while it is suppose to signal a release
// fence. Signal the dummy fence here.
- if (fence_state_->load(std::memory_order_acquire) &
- channel->client_state_mask()) {
+ if (fence_state_->load(std::memory_order_acquire) & consumer_state_mask) {
epoll_event event;
event.events = EPOLLIN;
- event.data.u64 = channel->client_state_mask();
+ event.data.u64 = consumer_state_mask;
if (epoll_ctl(release_fence_fd_.Get(), EPOLL_CTL_MOD,
dummy_fence_fd_.Get(), &event) < 0) {
ALOGE(
- "ProducerChannel::RemoveConsumer: Failed to modify the shared "
- "release fence to include the dummy fence: %s",
- strerror(errno));
+ "%s: Failed to modify the shared release fence to include the "
+ "dummy fence: %s",
+ __FUNCTION__, strerror(errno));
return;
}
- ALOGW(
- "ProducerChannel::RemoveConsumer: signal dummy release fence "
- "buffer_id=%d",
- buffer_id());
+ ALOGW("%s: signal dummy release fence buffer_id=%d", __FUNCTION__,
+ buffer_id());
eventfd_write(dummy_fence_fd_.Get(), 1);
}
}
}
-// Returns true if the given parameters match the underlying buffer parameters.
+// Returns true if the given parameters match the underlying buffer
+// parameters.
bool ProducerChannel::CheckParameters(uint32_t width, uint32_t height,
uint32_t layer_count, uint32_t format,
uint64_t usage,