content/common/gpu/gpu

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This source file includes following definitions.
a_stub_is_descheduled_
OnFilterAdded
OnFilterRemoved
OnMessageReceived
MessageProcessed
SetPreemptingFlagAndSchedulingState
UpdateStubSchedulingState
Send
UpdatePreemptionState
TransitionToIdleIfCaughtUp
TransitionToIdle
TransitionToWaiting
TransitionToChecking
TransitionToPreempting
TransitionToWouldPreemptDescheduled
InsertSyncPointOnMainThread
DeleteWeakPtrOnMainThread
num_stubs_descheduled_
Init
GetChannelName
TakeRendererFileDescriptor
OnMessageReceived
OnChannelError
Send
RequeueMessage
OnScheduled
StubSchedulingChanged
CreateViewCommandBuffer
LookupCommandBuffer
CreateImage
DeleteImage
LoseAllContexts
MarkAllContextsLost
DestroySoon
GenerateRouteID
AddRoute
RemoveRoute
GetPreemptionFlag
SetPreemptByFlag
OnDestroy
OnControlMessageReceived
HandleMessage
OnCreateOffscreenCommandBuffer
OnDestroyCommandBuffer
OnDevToolsStartEventsRecording
OnDevToolsStopEventsRecording
MessageProcessed
CacheShader
AddFilter
RemoveFilter
GetMemoryUsage
// 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.

#if defined(OS_WIN)
#include <windows.h>
#endif

#include "content/common/gpu/gpu_channel.h"

#include <queue>
#include <vector>

#include "base/bind.h"
#include "base/command_line.h"
#include "base/debug/trace_event.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/strings/string_util.h"
#include "base/timer/timer.h"
#include "content/common/gpu/devtools_gpu_agent.h"
#include "content/common/gpu/gpu_channel_manager.h"
#include "content/common/gpu/gpu_messages.h"
#include "content/common/gpu/sync_point_manager.h"
#include "content/public/common/content_switches.h"
#include "gpu/command_buffer/common/mailbox.h"
#include "gpu/command_buffer/service/gpu_scheduler.h"
#include "gpu/command_buffer/service/image_manager.h"
#include "gpu/command_buffer/service/mailbox_manager.h"
#include "ipc/ipc_channel.h"
#include "ipc/ipc_channel_proxy.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_image.h"
#include "ui/gl/gl_surface.h"

#if defined(OS_POSIX)
#include "ipc/ipc_channel_posix.h"
#endif

namespace content {
namespace {

// Number of milliseconds between successive vsync. Many GL commands block
// on vsync, so thresholds for preemption should be multiples of this.
const int64 kVsyncIntervalMs = 17;

// Amount of time that we will wait for an IPC to be processed before
// preempting. After a preemption, we must wait this long before triggering
// another preemption.
const int64 kPreemptWaitTimeMs = 2 * kVsyncIntervalMs;

// Once we trigger a preemption, the maximum duration that we will wait
// before clearing the preemption.
const int64 kMaxPreemptTimeMs = kVsyncIntervalMs;

// Stop the preemption once the time for the longest pending IPC drops
// below this threshold.
const int64 kStopPreemptThresholdMs = kVsyncIntervalMs;

}  // anonymous namespace

// This filter does three things:
// - it counts and timestamps each message forwarded to the channel
//   so that we can preempt other channels if a message takes too long to
//   process. To guarantee fairness, we must wait a minimum amount of time
//   before preempting and we limit the amount of time that we can preempt in
//   one shot (see constants above).
// - it handles the GpuCommandBufferMsg_InsertSyncPoint message on the IO
//   thread, generating the sync point ID and responding immediately, and then
//   posting a task to insert the GpuCommandBufferMsg_RetireSyncPoint message
//   into the channel's queue.
// - it generates mailbox names for clients of the GPU process on the IO thread.
class GpuChannelMessageFilter : public IPC::ChannelProxy::MessageFilter {
 public:
  // Takes ownership of gpu_channel (see below).
  GpuChannelMessageFilter(base::WeakPtr<GpuChannel>* gpu_channel,
                          scoped_refptr<SyncPointManager> sync_point_manager,
                          scoped_refptr<base::MessageLoopProxy> message_loop)
      : preemption_state_(IDLE),
        gpu_channel_(gpu_channel),
        channel_(NULL),
        sync_point_manager_(sync_point_manager),
        message_loop_(message_loop),
        messages_forwarded_to_channel_(0),
        a_stub_is_descheduled_(false) {
  }

  virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE {
    DCHECK(!channel_);
    channel_ = channel;
  }

  virtual void OnFilterRemoved() OVERRIDE {
    DCHECK(channel_);
    channel_ = NULL;
  }

  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
    DCHECK(channel_);

    bool handled = false;
    if (message.type() == GpuCommandBufferMsg_RetireSyncPoint::ID) {
      // This message should not be sent explicitly by the renderer.
      DLOG(ERROR) << "Client should not send "
                     "GpuCommandBufferMsg_RetireSyncPoint message";
      handled = true;
    }

    // All other messages get processed by the GpuChannel.
    if (!handled) {
      messages_forwarded_to_channel_++;
      if (preempting_flag_.get())
        pending_messages_.push(PendingMessage(messages_forwarded_to_channel_));
      UpdatePreemptionState();
    }

    if (message.type() == GpuCommandBufferMsg_InsertSyncPoint::ID) {
      uint32 sync_point = sync_point_manager_->GenerateSyncPoint();
      IPC::Message* reply = IPC::SyncMessage::GenerateReply(&message);
      GpuCommandBufferMsg_InsertSyncPoint::WriteReplyParams(reply, sync_point);
      Send(reply);
      message_loop_->PostTask(FROM_HERE, base::Bind(
          &GpuChannelMessageFilter::InsertSyncPointOnMainThread,
          gpu_channel_,
          sync_point_manager_,
          message.routing_id(),
          sync_point));
      handled = true;
    }
    return handled;
  }

  void MessageProcessed(uint64 messages_processed) {
    while (!pending_messages_.empty() &&
           pending_messages_.front().message_number <= messages_processed)
      pending_messages_.pop();
    UpdatePreemptionState();
  }

  void SetPreemptingFlagAndSchedulingState(
      gpu::PreemptionFlag* preempting_flag,
      bool a_stub_is_descheduled) {
    preempting_flag_ = preempting_flag;
    a_stub_is_descheduled_ = a_stub_is_descheduled;
  }

  void UpdateStubSchedulingState(bool a_stub_is_descheduled) {
    a_stub_is_descheduled_ = a_stub_is_descheduled;
    UpdatePreemptionState();
  }

  bool Send(IPC::Message* message) {
    return channel_->Send(message);
  }

 protected:
  virtual ~GpuChannelMessageFilter() {
    message_loop_->PostTask(FROM_HERE, base::Bind(
        &GpuChannelMessageFilter::DeleteWeakPtrOnMainThread, gpu_channel_));
  }

 private:
  enum PreemptionState {
    // Either there's no other channel to preempt, there are no messages
    // pending processing, or we just finished preempting and have to wait
    // before preempting again.
    IDLE,
    // We are waiting kPreemptWaitTimeMs before checking if we should preempt.
    WAITING,
    // We can preempt whenever any IPC processing takes more than
    // kPreemptWaitTimeMs.
    CHECKING,
    // We are currently preempting (i.e. no stub is descheduled).
    PREEMPTING,
    // We would like to preempt, but some stub is descheduled.
    WOULD_PREEMPT_DESCHEDULED,
  };

  PreemptionState preemption_state_;

  // Maximum amount of time that we can spend in PREEMPTING.
  // It is reset when we transition to IDLE.
  base::TimeDelta max_preemption_time_;

  struct PendingMessage {
    uint64 message_number;
    base::TimeTicks time_received;

    explicit PendingMessage(uint64 message_number)
        : message_number(message_number),
          time_received(base::TimeTicks::Now()) {
    }
  };

  void UpdatePreemptionState() {
    switch (preemption_state_) {
      case IDLE:
        if (preempting_flag_.get() && !pending_messages_.empty())
          TransitionToWaiting();
        break;
      case WAITING:
        // A timer will transition us to CHECKING.
        DCHECK(timer_.IsRunning());
        break;
      case CHECKING:
        if (!pending_messages_.empty()) {
          base::TimeDelta time_elapsed =
              base::TimeTicks::Now() - pending_messages_.front().time_received;
          if (time_elapsed.InMilliseconds() < kPreemptWaitTimeMs) {
            // Schedule another check for when the IPC may go long.
            timer_.Start(
                FROM_HERE,
                base::TimeDelta::FromMilliseconds(kPreemptWaitTimeMs) -
                    time_elapsed,
                this, &GpuChannelMessageFilter::UpdatePreemptionState);
          } else {
            if (a_stub_is_descheduled_)
              TransitionToWouldPreemptDescheduled();
            else
              TransitionToPreempting();
          }
        }
        break;
      case PREEMPTING:
        // A TransitionToIdle() timer should always be running in this state.
        DCHECK(timer_.IsRunning());
        if (a_stub_is_descheduled_)
          TransitionToWouldPreemptDescheduled();
        else
          TransitionToIdleIfCaughtUp();
        break;
      case WOULD_PREEMPT_DESCHEDULED:
        // A TransitionToIdle() timer should never be running in this state.
        DCHECK(!timer_.IsRunning());
        if (!a_stub_is_descheduled_)
          TransitionToPreempting();
        else
          TransitionToIdleIfCaughtUp();
        break;
      default:
        NOTREACHED();
    }
  }

  void TransitionToIdleIfCaughtUp() {
    DCHECK(preemption_state_ == PREEMPTING ||
           preemption_state_ == WOULD_PREEMPT_DESCHEDULED);
    if (pending_messages_.empty()) {
      TransitionToIdle();
    } else {
      base::TimeDelta time_elapsed =
          base::TimeTicks::Now() - pending_messages_.front().time_received;
      if (time_elapsed.InMilliseconds() < kStopPreemptThresholdMs)
        TransitionToIdle();
    }
  }

  void TransitionToIdle() {
    DCHECK(preemption_state_ == PREEMPTING ||
           preemption_state_ == WOULD_PREEMPT_DESCHEDULED);
    // Stop any outstanding timer set to force us from PREEMPTING to IDLE.
    timer_.Stop();

    preemption_state_ = IDLE;
    preempting_flag_->Reset();
    TRACE_COUNTER_ID1("gpu", "GpuChannel::Preempting", this, 0);

    UpdatePreemptionState();
  }

  void TransitionToWaiting() {
    DCHECK_EQ(preemption_state_, IDLE);
    DCHECK(!timer_.IsRunning());

    preemption_state_ = WAITING;
    timer_.Start(
        FROM_HERE,
        base::TimeDelta::FromMilliseconds(kPreemptWaitTimeMs),
        this, &GpuChannelMessageFilter::TransitionToChecking);
  }

  void TransitionToChecking() {
    DCHECK_EQ(preemption_state_, WAITING);
    DCHECK(!timer_.IsRunning());

    preemption_state_ = CHECKING;
    max_preemption_time_ = base::TimeDelta::FromMilliseconds(kMaxPreemptTimeMs);
    UpdatePreemptionState();
  }

  void TransitionToPreempting() {
    DCHECK(preemption_state_ == CHECKING ||
           preemption_state_ == WOULD_PREEMPT_DESCHEDULED);
    DCHECK(!a_stub_is_descheduled_);

    // Stop any pending state update checks that we may have queued
    // while CHECKING.
    if (preemption_state_ == CHECKING)
      timer_.Stop();

    preemption_state_ = PREEMPTING;
    preempting_flag_->Set();
    TRACE_COUNTER_ID1("gpu", "GpuChannel::Preempting", this, 1);

    timer_.Start(
       FROM_HERE,
       max_preemption_time_,
       this, &GpuChannelMessageFilter::TransitionToIdle);

    UpdatePreemptionState();
  }

  void TransitionToWouldPreemptDescheduled() {
    DCHECK(preemption_state_ == CHECKING ||
           preemption_state_ == PREEMPTING);
    DCHECK(a_stub_is_descheduled_);

    if (preemption_state_ == CHECKING) {
      // Stop any pending state update checks that we may have queued
      // while CHECKING.
      timer_.Stop();
    } else {
      // Stop any TransitionToIdle() timers that we may have queued
      // while PREEMPTING.
      timer_.Stop();
      max_preemption_time_ = timer_.desired_run_time() - base::TimeTicks::Now();
      if (max_preemption_time_ < base::TimeDelta()) {
        TransitionToIdle();
        return;
      }
    }

    preemption_state_ = WOULD_PREEMPT_DESCHEDULED;
    preempting_flag_->Reset();
    TRACE_COUNTER_ID1("gpu", "GpuChannel::Preempting", this, 0);

    UpdatePreemptionState();
  }

  static void InsertSyncPointOnMainThread(
      base::WeakPtr<GpuChannel>* gpu_channel,
      scoped_refptr<SyncPointManager> manager,
      int32 routing_id,
      uint32 sync_point) {
    // This function must ensure that the sync point will be retired. Normally
    // we'll find the stub based on the routing ID, and associate the sync point
    // with it, but if that fails for any reason (channel or stub already
    // deleted, invalid routing id), we need to retire the sync point
    // immediately.
    if (gpu_channel->get()) {
      GpuCommandBufferStub* stub = gpu_channel->get()->LookupCommandBuffer(
          routing_id);
      if (stub) {
        stub->AddSyncPoint(sync_point);
        GpuCommandBufferMsg_RetireSyncPoint message(routing_id, sync_point);
        gpu_channel->get()->OnMessageReceived(message);
        return;
      } else {
        gpu_channel->get()->MessageProcessed();
      }
    }
    manager->RetireSyncPoint(sync_point);
  }

  static void DeleteWeakPtrOnMainThread(
      base::WeakPtr<GpuChannel>* gpu_channel) {
    delete gpu_channel;
  }

  // NOTE: this is a pointer to a weak pointer. It is never dereferenced on the
  // IO thread, it's only passed through - therefore the WeakPtr assumptions are
  // respected.
  base::WeakPtr<GpuChannel>* gpu_channel_;
  IPC::Channel* channel_;
  scoped_refptr<SyncPointManager> sync_point_manager_;
  scoped_refptr<base::MessageLoopProxy> message_loop_;
  scoped_refptr<gpu::PreemptionFlag> preempting_flag_;

  std::queue<PendingMessage> pending_messages_;

  // Count of the number of IPCs forwarded to the GpuChannel.
  uint64 messages_forwarded_to_channel_;

  base::OneShotTimer<GpuChannelMessageFilter> timer_;

  bool a_stub_is_descheduled_;
};

GpuChannel::GpuChannel(GpuChannelManager* gpu_channel_manager,
                       GpuWatchdog* watchdog,
                       gfx::GLShareGroup* share_group,
                       gpu::gles2::MailboxManager* mailbox,
                       int client_id,
                       bool software)
    : gpu_channel_manager_(gpu_channel_manager),
      messages_processed_(0),
      client_id_(client_id),
      share_group_(share_group ? share_group : new gfx::GLShareGroup),
      mailbox_manager_(mailbox ? mailbox : new gpu::gles2::MailboxManager),
      image_manager_(new gpu::gles2::ImageManager),
      watchdog_(watchdog),
      software_(software),
      handle_messages_scheduled_(false),
      processed_get_state_fast_(false),
      currently_processing_message_(NULL),
      weak_factory_(this),
      num_stubs_descheduled_(0) {
  DCHECK(gpu_channel_manager);
  DCHECK(client_id);

  channel_id_ = IPC::Channel::GenerateVerifiedChannelID("gpu");
  const CommandLine* command_line = CommandLine::ForCurrentProcess();
  log_messages_ = command_line->HasSwitch(switches::kLogPluginMessages);
}


void GpuChannel::Init(base::MessageLoopProxy* io_message_loop,
                      base::WaitableEvent* shutdown_event) {
  DCHECK(!channel_.get());

  // Map renderer ID to a (single) channel to that process.
  channel_.reset(new IPC::SyncChannel(
      channel_id_,
      IPC::Channel::MODE_SERVER,
      this,
      io_message_loop,
      false,
      shutdown_event));

  base::WeakPtr<GpuChannel>* weak_ptr(new base::WeakPtr<GpuChannel>(
      weak_factory_.GetWeakPtr()));

  filter_ = new GpuChannelMessageFilter(
      weak_ptr,
      gpu_channel_manager_->sync_point_manager(),
      base::MessageLoopProxy::current());
  io_message_loop_ = io_message_loop;
  channel_->AddFilter(filter_.get());

  devtools_gpu_agent_.reset(new DevToolsGpuAgent(this));
}

std::string GpuChannel::GetChannelName() {
  return channel_id_;
}

#if defined(OS_POSIX)
int GpuChannel::TakeRendererFileDescriptor() {
  if (!channel_) {
    NOTREACHED();
    return -1;
  }
  return channel_->TakeClientFileDescriptor();
}
#endif  // defined(OS_POSIX)

bool GpuChannel::OnMessageReceived(const IPC::Message& message) {
  if (log_messages_) {
    DVLOG(1) << "received message @" << &message << " on channel @" << this
             << " with type " << message.type();
  }

  if (message.type() == GpuCommandBufferMsg_GetStateFast::ID) {
    if (processed_get_state_fast_) {
      // Require a non-GetStateFast message in between two GetStateFast
      // messages, to ensure progress is made.
      std::deque<IPC::Message*>::iterator point = deferred_messages_.begin();

      while (point != deferred_messages_.end() &&
             (*point)->type() == GpuCommandBufferMsg_GetStateFast::ID) {
        ++point;
      }

      if (point != deferred_messages_.end()) {
        ++point;
      }

      deferred_messages_.insert(point, new IPC::Message(message));
    } else {
      // Move GetStateFast commands to the head of the queue, so the renderer
      // doesn't have to wait any longer than necessary.
      deferred_messages_.push_front(new IPC::Message(message));
    }
  } else {
    deferred_messages_.push_back(new IPC::Message(message));
  }

  OnScheduled();

  return true;
}

void GpuChannel::OnChannelError() {
  gpu_channel_manager_->RemoveChannel(client_id_);
}

bool GpuChannel::Send(IPC::Message* message) {
  // The GPU process must never send a synchronous IPC message to the renderer
  // process. This could result in deadlock.
  DCHECK(!message->is_sync());
  if (log_messages_) {
    DVLOG(1) << "sending message @" << message << " on channel @" << this
             << " with type " << message->type();
  }

  if (!channel_) {
    delete message;
    return false;
  }

  return channel_->Send(message);
}

void GpuChannel::RequeueMessage() {
  DCHECK(currently_processing_message_);
  deferred_messages_.push_front(
      new IPC::Message(*currently_processing_message_));
  messages_processed_--;
  currently_processing_message_ = NULL;
}

void GpuChannel::OnScheduled() {
  if (handle_messages_scheduled_)
    return;
  // Post a task to handle any deferred messages. The deferred message queue is
  // not emptied here, which ensures that OnMessageReceived will continue to
  // defer newly received messages until the ones in the queue have all been
  // handled by HandleMessage. HandleMessage is invoked as a
  // task to prevent reentrancy.
  base::MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&GpuChannel::HandleMessage, weak_factory_.GetWeakPtr()));
  handle_messages_scheduled_ = true;
}

void GpuChannel::StubSchedulingChanged(bool scheduled) {
  bool a_stub_was_descheduled = num_stubs_descheduled_ > 0;
  if (scheduled) {
    num_stubs_descheduled_--;
    OnScheduled();
  } else {
    num_stubs_descheduled_++;
  }
  DCHECK_LE(num_stubs_descheduled_, stubs_.size());
  bool a_stub_is_descheduled = num_stubs_descheduled_ > 0;

  if (a_stub_is_descheduled != a_stub_was_descheduled) {
    if (preempting_flag_.get()) {
      io_message_loop_->PostTask(
          FROM_HERE,
          base::Bind(&GpuChannelMessageFilter::UpdateStubSchedulingState,
                     filter_,
                     a_stub_is_descheduled));
    }
  }
}

void GpuChannel::CreateViewCommandBuffer(
    const gfx::GLSurfaceHandle& window,
    int32 surface_id,
    const GPUCreateCommandBufferConfig& init_params,
    int32* route_id) {
  TRACE_EVENT1("gpu",
               "GpuChannel::CreateViewCommandBuffer",
               "surface_id",
               surface_id);

  *route_id = MSG_ROUTING_NONE;

  GpuCommandBufferStub* share_group = stubs_.Lookup(init_params.share_group_id);

  // Virtualize compositor contexts on OS X to prevent performance regressions
  // when enabling FCM.
  // http://crbug.com/180463
  bool use_virtualized_gl_context = false;
#if defined(OS_MACOSX)
  use_virtualized_gl_context = true;
#endif

  *route_id = GenerateRouteID();
  scoped_ptr<GpuCommandBufferStub> stub(
      new GpuCommandBufferStub(this,
                               share_group,
                               window,
                               mailbox_manager_.get(),
                               image_manager_.get(),
                               gfx::Size(),
                               disallowed_features_,
                               init_params.attribs,
                               init_params.gpu_preference,
                               use_virtualized_gl_context,
                               *route_id,
                               surface_id,
                               watchdog_,
                               software_,
                               init_params.active_url));
  if (preempted_flag_.get())
    stub->SetPreemptByFlag(preempted_flag_);
  router_.AddRoute(*route_id, stub.get());
  stubs_.AddWithID(stub.release(), *route_id);
}

GpuCommandBufferStub* GpuChannel::LookupCommandBuffer(int32 route_id) {
  return stubs_.Lookup(route_id);
}

void GpuChannel::CreateImage(
    gfx::PluginWindowHandle window,
    int32 image_id,
    gfx::Size* size) {
  TRACE_EVENT1("gpu",
               "GpuChannel::CreateImage",
               "image_id",
               image_id);

  *size = gfx::Size();

  if (image_manager_->LookupImage(image_id)) {
    LOG(ERROR) << "CreateImage failed, image_id already in use.";
    return;
  }

  scoped_refptr<gfx::GLImage> image = gfx::GLImage::CreateGLImage(window);
  if (!image.get())
    return;

  image_manager_->AddImage(image.get(), image_id);
  *size = image->GetSize();
}

void GpuChannel::DeleteImage(int32 image_id) {
  TRACE_EVENT1("gpu",
               "GpuChannel::DeleteImage",
               "image_id",
               image_id);

  image_manager_->RemoveImage(image_id);
}

void GpuChannel::LoseAllContexts() {
  gpu_channel_manager_->LoseAllContexts();
}

void GpuChannel::MarkAllContextsLost() {
  for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
       !it.IsAtEnd(); it.Advance()) {
    it.GetCurrentValue()->MarkContextLost();
  }
}

void GpuChannel::DestroySoon() {
  base::MessageLoop::current()->PostTask(
      FROM_HERE, base::Bind(&GpuChannel::OnDestroy, this));
}

int32 GpuChannel::GenerateRouteID() {
  static int32 last_id = 0;
  return ++last_id;
}

void GpuChannel::AddRoute(int32 route_id, IPC::Listener* listener) {
  router_.AddRoute(route_id, listener);
}

void GpuChannel::RemoveRoute(int32 route_id) {
  router_.RemoveRoute(route_id);
}

gpu::PreemptionFlag* GpuChannel::GetPreemptionFlag() {
  if (!preempting_flag_.get()) {
    preempting_flag_ = new gpu::PreemptionFlag;
    io_message_loop_->PostTask(
        FROM_HERE, base::Bind(
            &GpuChannelMessageFilter::SetPreemptingFlagAndSchedulingState,
            filter_, preempting_flag_, num_stubs_descheduled_ > 0));
  }
  return preempting_flag_.get();
}

void GpuChannel::SetPreemptByFlag(
    scoped_refptr<gpu::PreemptionFlag> preempted_flag) {
  preempted_flag_ = preempted_flag;

  for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
       !it.IsAtEnd(); it.Advance()) {
    it.GetCurrentValue()->SetPreemptByFlag(preempted_flag_);
  }
}

GpuChannel::~GpuChannel() {
  if (preempting_flag_.get())
    preempting_flag_->Reset();
}

void GpuChannel::OnDestroy() {
  TRACE_EVENT0("gpu", "GpuChannel::OnDestroy");
  gpu_channel_manager_->RemoveChannel(client_id_);
}

bool GpuChannel::OnControlMessageReceived(const IPC::Message& msg) {
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(GpuChannel, msg)
    IPC_MESSAGE_HANDLER(GpuChannelMsg_CreateOffscreenCommandBuffer,
                        OnCreateOffscreenCommandBuffer)
    IPC_MESSAGE_HANDLER(GpuChannelMsg_DestroyCommandBuffer,
                        OnDestroyCommandBuffer)
    IPC_MESSAGE_HANDLER(GpuChannelMsg_DevToolsStartEventsRecording,
                        OnDevToolsStartEventsRecording)
    IPC_MESSAGE_HANDLER(GpuChannelMsg_DevToolsStopEventsRecording,
                        OnDevToolsStopEventsRecording)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()
  DCHECK(handled) << msg.type();
  return handled;
}

void GpuChannel::HandleMessage() {
  handle_messages_scheduled_ = false;
  if (deferred_messages_.empty())
    return;

  bool should_fast_track_ack = false;
  IPC::Message* m = deferred_messages_.front();
  GpuCommandBufferStub* stub = stubs_.Lookup(m->routing_id());

  do {
    if (stub) {
      if (!stub->IsScheduled())
        return;
      if (stub->IsPreempted()) {
        OnScheduled();
        return;
      }
    }

    scoped_ptr<IPC::Message> message(m);
    deferred_messages_.pop_front();
    bool message_processed = true;

    processed_get_state_fast_ =
        (message->type() == GpuCommandBufferMsg_GetStateFast::ID);

    currently_processing_message_ = message.get();
    bool result;
    if (message->routing_id() == MSG_ROUTING_CONTROL)
      result = OnControlMessageReceived(*message);
    else
      result = router_.RouteMessage(*message);
    currently_processing_message_ = NULL;

    if (!result) {
      // Respond to sync messages even if router failed to route.
      if (message->is_sync()) {
        IPC::Message* reply = IPC::SyncMessage::GenerateReply(&*message);
        reply->set_reply_error();
        Send(reply);
      }
    } else {
      // If the command buffer becomes unscheduled as a result of handling the
      // message but still has more commands to process, synthesize an IPC
      // message to flush that command buffer.
      if (stub) {
        if (stub->HasUnprocessedCommands()) {
          deferred_messages_.push_front(new GpuCommandBufferMsg_Rescheduled(
              stub->route_id()));
          message_processed = false;
        }
      }
    }
    if (message_processed)
      MessageProcessed();

    // We want the EchoACK following the SwapBuffers to be sent as close as
    // possible, avoiding scheduling other channels in the meantime.
    should_fast_track_ack = false;
    if (!deferred_messages_.empty()) {
      m = deferred_messages_.front();
      stub = stubs_.Lookup(m->routing_id());
      should_fast_track_ack =
          (m->type() == GpuCommandBufferMsg_Echo::ID) &&
          stub && stub->IsScheduled();
    }
  } while (should_fast_track_ack);

  if (!deferred_messages_.empty()) {
    OnScheduled();
  }
}

void GpuChannel::OnCreateOffscreenCommandBuffer(
    const gfx::Size& size,
    const GPUCreateCommandBufferConfig& init_params,
    int32* route_id) {
  TRACE_EVENT0("gpu", "GpuChannel::OnCreateOffscreenCommandBuffer");
  GpuCommandBufferStub* share_group = stubs_.Lookup(init_params.share_group_id);

  *route_id = GenerateRouteID();

  scoped_ptr<GpuCommandBufferStub> stub(new GpuCommandBufferStub(
      this,
      share_group,
      gfx::GLSurfaceHandle(),
      mailbox_manager_.get(),
      image_manager_.get(),
      size,
      disallowed_features_,
      init_params.attribs,
      init_params.gpu_preference,
      false,
      *route_id,
      0,
      watchdog_,
      software_,
      init_params.active_url));
  if (preempted_flag_.get())
    stub->SetPreemptByFlag(preempted_flag_);
  router_.AddRoute(*route_id, stub.get());
  stubs_.AddWithID(stub.release(), *route_id);
  TRACE_EVENT1("gpu", "GpuChannel::OnCreateOffscreenCommandBuffer",
               "route_id", route_id);
}

void GpuChannel::OnDestroyCommandBuffer(int32 route_id) {
  TRACE_EVENT1("gpu", "GpuChannel::OnDestroyCommandBuffer",
               "route_id", route_id);

  GpuCommandBufferStub* stub = stubs_.Lookup(route_id);
  if (!stub)
    return;
  bool need_reschedule = (stub && !stub->IsScheduled());
  router_.RemoveRoute(route_id);
  stubs_.Remove(route_id);
  // In case the renderer is currently blocked waiting for a sync reply from the
  // stub, we need to make sure to reschedule the GpuChannel here.
  if (need_reschedule) {
    // This stub won't get a chance to reschedule, so update the count now.
    StubSchedulingChanged(true);
  }
}

void GpuChannel::OnDevToolsStartEventsRecording(int32* route_id) {
  devtools_gpu_agent_->StartEventsRecording(route_id);
}

void GpuChannel::OnDevToolsStopEventsRecording() {
  devtools_gpu_agent_->StopEventsRecording();
}

void GpuChannel::MessageProcessed() {
  messages_processed_++;
  if (preempting_flag_.get()) {
    io_message_loop_->PostTask(
        FROM_HERE,
        base::Bind(&GpuChannelMessageFilter::MessageProcessed,
                   filter_,
                   messages_processed_));
  }
}

void GpuChannel::CacheShader(const std::string& key,
                             const std::string& shader) {
  gpu_channel_manager_->Send(
      new GpuHostMsg_CacheShader(client_id_, key, shader));
}

void GpuChannel::AddFilter(IPC::ChannelProxy::MessageFilter* filter) {
  channel_->AddFilter(filter);
}

void GpuChannel::RemoveFilter(IPC::ChannelProxy::MessageFilter* filter) {
  channel_->RemoveFilter(filter);
}

uint64 GpuChannel::GetMemoryUsage() {
  uint64 size = 0;
  for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
       !it.IsAtEnd(); it.Advance()) {
    size += it.GetCurrentValue()->GetMemoryUsage();
  }
  return size;
}

}  // namespace content
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root/content/common/gpu/gpu_channel.cc

DEFINITIONS
