gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/service/command_buffer_service.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/command_buffer_service.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/debug/trace_event.h"
 #include "gpu/command_buffer/common/cmd_buffer_common.h"
 #include "gpu/command_buffer/common/command_buffer_shared.h"
 #include "gpu/command_buffer/service/transfer_buffer_manager.h"
 
 using ::base::SharedMemory;
+using ::base::AutoLock;
 
 namespace gpu {
 
 CommandBufferService::CommandBufferService(
     TransferBufferManagerInterface* transfer_buffer_manager)
     : ring_buffer_id_(-1),
       shared_state_(NULL),
       num_entries_(0),
       get_offset_(0),
       put_offset_(0),
       transfer_buffer_manager_(transfer_buffer_manager),
       token_(0),
+      async_token_(0),
       generation_(0),
       error_(error::kNoError),
       context_lost_reason_(error::kUnknown) {
 }
 
 CommandBufferService::~CommandBufferService() {
 }
 
 bool CommandBufferService::Initialize() {
   return true;
 }
 
 CommandBufferService::State CommandBufferService::GetState() {
+  AutoLock lock(lock_);
+  return GetStateImpl();
+}
+
+CommandBufferService::State CommandBufferService::GetStateImpl() {

[reveman, 2014/01/22 17:30:04]

Please add a lock_.AssertAcquired() call here to protect against this being
called without first acquiring |lock_|.

   State state;
   state.num_entries = num_entries_;
   state.get_offset = get_offset_;
   state.put_offset = put_offset_;
   state.token = token_;
+  state.async_token = async_token_;
   state.error = error_;
   state.context_lost_reason = context_lost_reason_;
   state.generation = ++generation_;
 
   return state;
 }
 
 CommandBufferService::State CommandBufferService::GetLastState() {
   return GetState();
 }
 
 int32 CommandBufferService::GetLastToken() {
   return GetState().token;
 }
 
 void CommandBufferService::UpdateState() {
+  AutoLock lock(lock_);
   if (shared_state_) {
-    CommandBufferService::State state = GetState();
+    CommandBufferService::State state = GetStateImpl();
     shared_state_->Write(state);
   }
 }
 
 CommandBufferService::State CommandBufferService::FlushSync(
     int32 put_offset, int32 last_known_get) {
   if (put_offset < 0 || put_offset > num_entries_) {
     error_ = gpu::error::kOutOfBounds;
     return GetState();
   }
@@ skipping 93 matching lines @@
   return transfer_buffer_manager_->RegisterTransferBuffer(id,
                                                           shared_memory,
                                                           size);
 }
 
 void CommandBufferService::SetToken(int32 token) {
   token_ = token;
   UpdateState();
 }
 
+void CommandBufferService::SetAsyncToken(uint32 token) {
+  async_token_ = token;

[reveman, 2014/01/22 17:30:04]

Do you need to acquire the lock before writing to |async_token_|?

+  UpdateState();
+}
+
 void CommandBufferService::SetParseError(error::Error error) {
   if (error_ == error::kNoError) {
     error_ = error;
     if (!parse_error_callback_.is_null())
       parse_error_callback_.Run();
   }
 }
 
 void CommandBufferService::SetContextLostReason(
     error::ContextLostReason reason) {
   context_lost_reason_ = reason;
 }
 
 void CommandBufferService::SetPutOffsetChangeCallback(
     const base::Closure& callback) {
   put_offset_change_callback_ = callback;
 }
 
 void CommandBufferService::SetGetBufferChangeCallback(
     const GetBufferChangedCallback& callback) {
   get_buffer_change_callback_ = callback;
 }
 
 void CommandBufferService::SetParseErrorCallback(
     const base::Closure& callback) {
   parse_error_callback_ = callback;
 }
 
 }  // namespace gpu