Implemented new fence syncs which replaces the old sync points.

gpu/command_buffer/service/sync_point_manager.cc

Index: gpu/command_buffer/service/sync_point_manager.cc
diff --git a/gpu/command_buffer/service/sync_point_manager.cc b/gpu/command_buffer/service/sync_point_manager.cc
index 039e494de8b1d4bd5ea3df100c89ec10cb508690..bc73adb2dacc4dd1d84b2ffcd8077e40b67f7da5 100644
--- a/gpu/command_buffer/service/sync_point_manager.cc
+++ b/gpu/command_buffer/service/sync_point_manager.cc
@@ -6,47 +6,281 @@
 
 #include <climits>
 
+#include "base/bind.h"
+#include "base/containers/hash_tables.h"
+#include "base/location.h"
 #include "base/logging.h"
 #include "base/rand_util.h"
 #include "base/sequence_checker.h"
+#include "base/single_thread_task_runner.h"
 
 namespace gpu {
 
 static const int kMaxSyncBase = INT_MAX;
 
-scoped_refptr<SyncPointClientState> SyncPointClientState::Create() {
-  return new SyncPointClientState;
+namespace {
+
+void RunOnThread(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+                 const base::Closure& callback) {
+  if (task_runner->BelongsToCurrentThread()) {
+    callback.Run();
+  } else {
+    task_runner->PostTask(FROM_HERE, callback);
+  }
+}
+
+}  // namespace
+
+scoped_refptr<SyncPointOrderData> SyncPointOrderData::Create() {
+  return new SyncPointOrderData;
 }
 
-uint32_t SyncPointClientState::GenerateUnprocessedOrderNumber(
+void SyncPointOrderData::Destroy() {
+  // Because of circular references between the SyncPointOrderData and
+  // SyncPointClientState, we must remove the references on destroy. Releasing
+  // the fence syncs in the order fence queue would be redundant at this point
+  // because they are assumed to be released on the destruction of the
+  // SyncPointClient.
+  base::AutoLock auto_lock(lock_);
+  destroyed_ = true;
+  while (!order_fence_queue_.empty()) {
+    order_fence_queue_.pop();
+  }
+}
+
+uint32_t SyncPointOrderData::GenerateUnprocessedOrderNumber(
     SyncPointManager* sync_point_manager) {
   const uint32_t order_num = sync_point_manager->GenerateOrderNumber();
-  base::subtle::Release_Store(&unprocessed_order_num_, order_num);
+  base::AutoLock auto_lock(lock_);
+  unprocessed_order_num_ = order_num;
   return order_num;
 }
 
-SyncPointClientState::SyncPointClientState()
-  : processed_order_num_(0),
-    unprocessed_order_num_(0),
-    current_order_num_(0) {
+void SyncPointOrderData::BeginProcessingOrderNumber(uint32_t order_num) {
+  DCHECK(processing_thread_checker_.CalledOnValidThread());
+  DCHECK_GE(order_num, current_order_num_);
+  current_order_num_ = order_num;
+
+  // Catch invalid waits which were waiting on fence syncs that do not exist.
+  // When we begin processing an order number, we should release any fence
+  // syncs which were enqueued but the order number never existed.
+  // Release without the lock to avoid possible deadlocks.
+  std::vector<OrderFence> ensure_releases;
+  {
+    base::AutoLock auto_lock(lock_);
+    while (!order_fence_queue_.empty()) {
+      const OrderFence& order_fence = order_fence_queue_.top();
+      if (order_fence_queue_.top().order_num < order_num) {
+        ensure_releases.push_back(order_fence);
+        order_fence_queue_.pop();
+        continue;
+      }
+      break;
+    }
+  }
+
+  for (OrderFence& order_fence : ensure_releases) {
+    order_fence.client_state->EnsureReleased(order_fence.fence_release);
+  }
 }
 
+void SyncPointOrderData::FinishProcessingOrderNumber(uint32_t order_num) {
+  DCHECK(processing_thread_checker_.CalledOnValidThread());
+  DCHECK_EQ(current_order_num_, order_num);
+
+  // Catch invalid waits which were waiting on fence syncs that do not exist.
+  // When we end processing an order number, we should release any fence syncs
+  // which were suppose to be released during this order number.
+  // Release without the lock to avoid possible deadlocks.
+  std::vector<OrderFence> ensure_releases;
+  {
+    base::AutoLock auto_lock(lock_);
+    DCHECK_GT(order_num, processed_order_num_);
+    processed_order_num_ = order_num;
+
+    while (!order_fence_queue_.empty()) {
+      const OrderFence& order_fence = order_fence_queue_.top();
+      if (order_fence_queue_.top().order_num <= order_num) {
+        ensure_releases.push_back(order_fence);
+        order_fence_queue_.pop();
+        continue;
+      }
+      break;
+    }
+  }
+
+  for (OrderFence& order_fence : ensure_releases) {
+    order_fence.client_state->EnsureReleased(order_fence.fence_release);
+  }
+}
+
+SyncPointOrderData::OrderFence::OrderFence(
+    uint32_t order,
+    uint64_t release,
+    scoped_refptr<SyncPointClientState> state)
+    : order_num(order), fence_release(release), client_state(state) {}
+
+SyncPointOrderData::OrderFence::~OrderFence() {}
+
+SyncPointOrderData::SyncPointOrderData()
+    : current_order_num_(0),
+      destroyed_(false),
+      processed_order_num_(0),
+      unprocessed_order_num_(0) {}
+
+SyncPointOrderData::~SyncPointOrderData() {}
+
+bool SyncPointOrderData::ValidateReleaseOrderNumber(
+    scoped_refptr<SyncPointClientState> client_state,
+    uint32_t wait_order_num,
+    uint64_t fence_release) {
+  base::AutoLock auto_lock(lock_);
+  if (destroyed_)
+    return false;
+
+  // Release should have a possible unprocessed order number lower
+  // than the wait order number.
+  if ((processed_order_num_ + 1) >= wait_order_num)
+    return false;
+
+  // Release should have more unprocessed numbers if we are waiting.
+  if (unprocessed_order_num_ <= processed_order_num_)
+    return false;
+
+  // So far it could be valid, but add an order fence guard to be sure it
+  // gets released eventually.
+  const uint32_t expected_order_num =
+      std::min(unprocessed_order_num_, wait_order_num);
+  order_fence_queue_.push(
+      OrderFence(expected_order_num, fence_release, client_state));
+  return true;
+}
+
+SyncPointClientState::ReleaseCallback::ReleaseCallback(
+    uint64_t release,
+    const base::Closure& callback)
+    : release_count(release), callback_closure(callback) {}
+
+SyncPointClientState::ReleaseCallback::~ReleaseCallback() {}
+
+SyncPointClientState::SyncPointClientState(
+    scoped_refptr<SyncPointOrderData> order_data)
+    : order_data_(order_data), fence_sync_release_(0) {}
+
 SyncPointClientState::~SyncPointClientState() {
 }
 
+bool SyncPointClientState::WaitForRelease(uint32_t wait_order_num,
+                                          uint64_t release,
+                                          const base::Closure& callback) {
+  // Lock must be held the whole time while we validate otherwise it could be
+  // released while we are checking.
+  {
+    base::AutoLock auto_lock(fence_sync_lock_);
+    if (release > fence_sync_release_) {
+      if (!order_data_->ValidateReleaseOrderNumber(this, wait_order_num,
+                                                   release)) {
+        return false;
+      } else {
+        // Add the callback which will be called upon release.
+        release_callback_queue_.push(ReleaseCallback(release, callback));
+        return true;
+      }
+    }
+  }
+
+  // Already released, run the callback now.
+  callback.Run();
+  return true;
+}
+
+void SyncPointClientState::ReleaseFenceSync(uint64_t release) {
+  // Call callbacks without the lock to avoid possible deadlocks.
+  std::vector<base::Closure> callback_list;
+  {
+    base::AutoLock auto_lock(fence_sync_lock_);
+    ReleaseFenceSyncLocked(release, &callback_list);
+  }
+
+  for (const base::Closure& closure : callback_list) {
+    closure.Run();
+  }
+}
+
+void SyncPointClientState::EnsureReleased(uint64_t release) {
+  // Call callbacks without the lock to avoid possible deadlocks.
+  std::vector<base::Closure> callback_list;
+  {
+    base::AutoLock auto_lock(fence_sync_lock_);
+    if (release <= fence_sync_release_)
+      return;
+
+    ReleaseFenceSyncLocked(release, &callback_list);
+  }
+
+  for (const base::Closure& closure : callback_list) {
+    closure.Run();
+  }
+}
+
+void SyncPointClientState::ReleaseFenceSyncLocked(
+    uint64_t release,
+    std::vector<base::Closure>* callback_list) {
+  fence_sync_lock_.AssertAcquired();
+  DCHECK_GT(release, fence_sync_release_);
+
+  fence_sync_release_ = release;
+  while (!release_callback_queue_.empty() &&
+         release_callback_queue_.top().release_count <= release) {
+    callback_list->push_back(release_callback_queue_.top().callback_closure);
+    release_callback_queue_.pop();
+  }
+}
+
 SyncPointClient::~SyncPointClient() {
+  // Release all fences on destruction.
+  ReleaseFenceSync(UINT64_MAX);
+
   sync_point_manager_->DestroySyncPointClient(namespace_id_, client_id_);
 }
 
+bool SyncPointClient::Wait(SyncPointClientState* release_state,
+                           uint64_t release_count,
+                           const base::Closure& wait_complete_callback) {
+  const uint32_t wait_order_number =
+      client_state_->order_data()->current_order_num();
+
+  // If waiting on self or wait was invalid, call the callback and return false.
+  if (client_state_ == release_state ||
+      !release_state->WaitForRelease(wait_order_number, release_count,
+                                     wait_complete_callback)) {
+    wait_complete_callback.Run();
+    return false;
+  }
+  return true;
+}
+
+bool SyncPointClient::WaitNonThreadSafe(
+    SyncPointClientState* release_state,
+    uint64_t release_count,
+    scoped_refptr<base::SingleThreadTaskRunner> runner,
+    const base::Closure& wait_complete_callback) {
+  return Wait(release_state, release_count,
+              base::Bind(&RunOnThread, runner, wait_complete_callback));
+}
+
+void SyncPointClient::ReleaseFenceSync(uint64_t release) {
+  client_state_->ReleaseFenceSync(release);
+}
+
 SyncPointClient::SyncPointClient(SyncPointManager* sync_point_manager,
-                                 scoped_refptr<SyncPointClientState> state,
+                                 scoped_refptr<SyncPointOrderData> order_data,
                                  CommandBufferNamespace namespace_id,
                                  uint64_t client_id)
-  : sync_point_manager_(sync_point_manager),
-    client_state_(state),
-    namespace_id_(namespace_id),
-    client_id_(client_id) {
-}
+    : sync_point_manager_(sync_point_manager),
+      client_state_(new SyncPointClientState(order_data)),
+      namespace_id_(namespace_id),
+      client_id_(client_id) {}
 
 SyncPointManager::SyncPointManager(bool allow_threaded_wait)
     : allow_threaded_wait_(allow_threaded_wait),
@@ -65,18 +299,17 @@ SyncPointManager::~SyncPointManager() {
 }
 
 scoped_ptr<SyncPointClient> SyncPointManager::CreateSyncPointClient(
-    scoped_refptr<SyncPointClientState> client_state,
-    CommandBufferNamespace namespace_id, uint64_t client_id) {
+    scoped_refptr<SyncPointOrderData> order_data,
+    CommandBufferNamespace namespace_id,
+    uint64_t client_id) {
   DCHECK_GE(namespace_id, 0);
   DCHECK_LT(static_cast<size_t>(namespace_id), arraysize(client_maps_));
   base::AutoLock auto_lock(client_maps_lock_);
 
   ClientMap& client_map = client_maps_[namespace_id];
   std::pair<ClientMap::iterator, bool> result = client_map.insert(
-      std::make_pair(client_id, new SyncPointClient(this,
-                                                    client_state,
-                                                    namespace_id,
-                                                    client_id)));
+      std::make_pair(client_id, new SyncPointClient(this, order_data,
+                                                    namespace_id, client_id)));
   DCHECK(result.second);
 
   return make_scoped_ptr(result.first->second);