base/threading: restrict to set only current thread priority

content/renderer/gpu/compositor_output_surface.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 "content/renderer/gpu/compositor_output_surface.h"
 
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_ack.h"
 #include "cc/output/managed_memory_policy.h"
 #include "cc/output/output_surface_client.h"
 #include "content/common/gpu/client/command_buffer_proxy_impl.h"
 #include "content/common/gpu/client/context_provider_command_buffer.h"
 #include "content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/gpu/frame_swap_message_queue.h"
 #include "content/renderer/render_thread_impl.h"
 #include "gpu/command_buffer/client/context_support.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "ipc/ipc_sync_channel.h"
 
-namespace {
-// There are several compositor surfaces in a process, but they share the same
-// compositor thread, so we use a simple int here to track prefer-smoothness.
-int g_prefer_smoothness_count = 0;
-} // namespace
-
 namespace content {
 
 CompositorOutputSurface::CompositorOutputSurface(
     int32 routing_id,
     uint32 output_surface_id,
     const scoped_refptr<ContextProviderCommandBuffer>& context_provider,
     const scoped_refptr<ContextProviderCommandBuffer>& worker_context_provider,
     scoped_ptr<cc::SoftwareOutputDevice> software_device,
     scoped_refptr<FrameSwapMessageQueue> swap_frame_message_queue,
     bool use_swap_compositor_frame_message)
     : OutputSurface(context_provider,
                     worker_context_provider,
                     software_device.Pass()),
       output_surface_id_(output_surface_id),
       use_swap_compositor_frame_message_(use_swap_compositor_frame_message),
       output_surface_filter_(
           RenderThreadImpl::current()->compositor_message_filter()),
       frame_swap_message_queue_(swap_frame_message_queue),
       routing_id_(routing_id),
+#if defined(OS_ANDROID)
       prefers_smoothness_(false),
-#if defined(OS_WIN)
-      // TODO(epenner): Implement PlatformThread::CurrentHandle() on windows.
-      main_thread_handle_(base::PlatformThreadHandle()),
-#else
-      main_thread_handle_(base::PlatformThread::CurrentHandle()),
+      main_thread_runner_(base::MessageLoop::current()->task_runner()),
 #endif
       layout_test_mode_(RenderThreadImpl::current()->layout_test_mode()),
       weak_ptrs_(this) {
   DCHECK(output_surface_filter_.get());
   DCHECK(frame_swap_message_queue_.get());
   DetachFromThread();
   capabilities_.max_frames_pending = 1;
   message_sender_ = RenderThreadImpl::current()->sync_message_filter();
   DCHECK(message_sender_.get());
 }
@@ skipping 139 matching lines @@
   // (e.g. after a lost context).
   if (output_surface_id != output_surface_id_)
     return;
   ReclaimResources(&ack);
 }
 
 bool CompositorOutputSurface::Send(IPC::Message* message) {
   return message_sender_->Send(message);
 }
 
+#if defined(OS_ANDROID)
 namespace {
-#if defined(OS_ANDROID)
-  void SetThreadPriorityToIdle(base::PlatformThreadHandle handle) {
-    base::PlatformThread::SetThreadPriority(handle,
-                                            base::ThreadPriority::BACKGROUND);
-  }
-  void SetThreadPriorityToDefault(base::PlatformThreadHandle handle) {
-    base::PlatformThread::SetThreadPriority(handle,
-                                            base::ThreadPriority::NORMAL);
-  }
-#else
-  void SetThreadPriorityToIdle(base::PlatformThreadHandle handle) {}
-  void SetThreadPriorityToDefault(base::PlatformThreadHandle handle) {}
-#endif
+void SetThreadPriorityToIdle() {
+  base::PlatformThread::SetCurrentThreadPriority(
+      base::ThreadPriority::BACKGROUND);
 }
+void SetThreadPriorityToDefault() {
+  base::PlatformThread::SetCurrentThreadPriority(
+      base::ThreadPriority::NORMAL);
+}
+}  // namespace
 
 void CompositorOutputSurface::UpdateSmoothnessTakesPriority(
     bool prefers_smoothness) {
-#ifndef NDEBUG
-  // If we use different compositor threads, we need to
-  // use an atomic int to track prefer smoothness count.
-  base::PlatformThreadId g_last_thread = base::PlatformThread::CurrentId();
-  DCHECK_EQ(g_last_thread, base::PlatformThread::CurrentId());
-#endif
   if (prefers_smoothness_ == prefers_smoothness)
     return;
-  // If this is the first surface to start preferring smoothness,
-  // Throttle the main thread's priority.
-  if (prefers_smoothness_ == false &&
-      ++g_prefer_smoothness_count == 1) {
-    SetThreadPriorityToIdle(main_thread_handle_);
+  prefers_smoothness_ = prefers_smoothness;
+  if (prefers_smoothness) {
+    main_thread_runner_->PostTask(
+        FROM_HERE, base::Bind(&SetThreadPriorityToIdle));
+  } else {
+    main_thread_runner_->PostTask(
+        FROM_HERE, base::Bind(&SetThreadPriorityToDefault));
   }
-  // If this is the last surface to stop preferring smoothness,
-  // Reset the main thread's priority to the default.
-  if (prefers_smoothness_ == true &&
-      --g_prefer_smoothness_count == 0) {
-    SetThreadPriorityToDefault(main_thread_handle_);
-  }
-  prefers_smoothness_ = prefers_smoothness;
 }
+#endif
 
 }  // namespace content