gpu: Reuse transfer buffers more aggresively

gpu/command_buffer/service/command_buffer_service.cc

Index: gpu/command_buffer/service/command_buffer_service.cc
diff --git a/gpu/command_buffer/service/command_buffer_service.cc b/gpu/command_buffer/service/command_buffer_service.cc
index bae2d801dd5021612ce6550bdcd7197c10082c72..02c255060ca745c823abd5be5289211bff86a7b3 100644
--- a/gpu/command_buffer/service/command_buffer_service.cc
+++ b/gpu/command_buffer/service/command_buffer_service.cc
@@ -13,6 +13,7 @@
 #include "gpu/command_buffer/service/transfer_buffer_manager.h"
 
 using ::base::SharedMemory;
+using ::base::AutoLock;
 
 namespace gpu {
 
@@ -25,6 +26,7 @@ CommandBufferService::CommandBufferService(
       put_offset_(0),
       transfer_buffer_manager_(transfer_buffer_manager),
       token_(0),
+      async_token_(0),
       generation_(0),
       error_(error::kNoError),
       context_lost_reason_(error::kUnknown) {
@@ -38,11 +40,17 @@ bool CommandBufferService::Initialize() {
 }
 
 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_;
@@ -59,8 +67,9 @@ int32 CommandBufferService::GetLastToken() {
 }
 
 void CommandBufferService::UpdateState() {
+  AutoLock lock(lock_);
   if (shared_state_) {
-    CommandBufferService::State state = GetState();
+    CommandBufferService::State state = GetStateImpl();
     shared_state_->Write(state);
   }
 }
@@ -174,6 +183,11 @@ void CommandBufferService::SetToken(int32 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;