src/content/common/gpu/gpu_channel.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #if defined(OS_WIN)
   6 #include <windows.h>
   7 #endif
   8
   9 #include "content/common/gpu/gpu_channel.h"
  10
  11 #include <queue>
  12 #include <vector>
  13
  14 #include "base/bind.h"
  15 #include "base/command_line.h"
  16 #include "base/debug/trace_event.h"
  17 #include "base/message_loop/message_loop_proxy.h"
  18 #include "base/strings/string_util.h"
  19 #include "base/timer/timer.h"
  20 #include "content/common/gpu/devtools_gpu_agent.h"
  21 #include "content/common/gpu/gpu_channel_manager.h"
  22 #include "content/common/gpu/gpu_messages.h"
  23 #include "content/common/gpu/sync_point_manager.h"
  24 #include "content/public/common/content_switches.h"
  25 #include "gpu/command_buffer/common/mailbox.h"
  26 #include "gpu/command_buffer/service/gpu_scheduler.h"
  27 #include "gpu/command_buffer/service/image_manager.h"
  28 #include "gpu/command_buffer/service/mailbox_manager.h"
  29 #include "ipc/ipc_channel.h"
  30 #include "ipc/message_filter.h"
  31 #include "ui/gl/gl_context.h"
  32 #include "ui/gl/gl_image.h"
  33 #include "ui/gl/gl_surface.h"
  34
  35 #if defined(OS_POSIX)
  36 #include "ipc/ipc_channel_posix.h"
  37 #endif
  38
  39 namespace content {
  40 namespace {
  41
  42 // Number of milliseconds between successive vsync. Many GL commands block
  43 // on vsync, so thresholds for preemption should be multiples of this.
  44 const int64 kVsyncIntervalMs = 17;
  45
  46 // Amount of time that we will wait for an IPC to be processed before
  47 // preempting. After a preemption, we must wait this long before triggering
  48 // another preemption.
  49 const int64 kPreemptWaitTimeMs = 2 * kVsyncIntervalMs;
  50
  51 // Once we trigger a preemption, the maximum duration that we will wait
  52 // before clearing the preemption.
  53 const int64 kMaxPreemptTimeMs = kVsyncIntervalMs;
  54
  55 // Stop the preemption once the time for the longest pending IPC drops
  56 // below this threshold.
  57 const int64 kStopPreemptThresholdMs = kVsyncIntervalMs;
  58
  59 }  // anonymous namespace
  60
  61 // This filter does three things:
  62 // - it counts and timestamps each message forwarded to the channel
  63 //   so that we can preempt other channels if a message takes too long to
  64 //   process. To guarantee fairness, we must wait a minimum amount of time
  65 //   before preempting and we limit the amount of time that we can preempt in
  66 //   one shot (see constants above).
  67 // - it handles the GpuCommandBufferMsg_InsertSyncPoint message on the IO
  68 //   thread, generating the sync point ID and responding immediately, and then
  69 //   posting a task to insert the GpuCommandBufferMsg_RetireSyncPoint message
  70 //   into the channel's queue.
  71 // - it generates mailbox names for clients of the GPU process on the IO thread.
  72 class GpuChannelMessageFilter : public IPC::MessageFilter {
  73  public:
  74   // Takes ownership of gpu_channel (see below).
  75   GpuChannelMessageFilter(base::WeakPtr<GpuChannel>* gpu_channel,
  76                           scoped_refptr<SyncPointManager> sync_point_manager,
  77                           scoped_refptr<base::MessageLoopProxy> message_loop)
  78       : preemption_state_(IDLE),
  79         gpu_channel_(gpu_channel),
  80         channel_(NULL),
  81         sync_point_manager_(sync_point_manager),
  82         message_loop_(message_loop),
  83         messages_forwarded_to_channel_(0),
  84         a_stub_is_descheduled_(false) {
  85   }
  86
  87   virtual void OnFilterAdded(IPC::Channel* channel) OVERRIDE {
  88     DCHECK(!channel_);
  89     channel_ = channel;
  90   }
  91
  92   virtual void OnFilterRemoved() OVERRIDE {
  93     DCHECK(channel_);
  94     channel_ = NULL;
  95   }
  96
  97   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
  98     DCHECK(channel_);
  99
 100     bool handled = false;
 101     if (message.type() == GpuCommandBufferMsg_RetireSyncPoint::ID) {
 102       // This message should not be sent explicitly by the renderer.
 103       DLOG(ERROR) << "Client should not send "
 104                      "GpuCommandBufferMsg_RetireSyncPoint message";
 105       handled = true;
 106     }
 107
 108     // All other messages get processed by the GpuChannel.
 109     if (!handled) {
 110       messages_forwarded_to_channel_++;
 111       if (preempting_flag_.get())
 112         pending_messages_.push(PendingMessage(messages_forwarded_to_channel_));
 113       UpdatePreemptionState();
 114     }
 115
 116     if (message.type() == GpuCommandBufferMsg_InsertSyncPoint::ID) {
 117       uint32 sync_point = sync_point_manager_->GenerateSyncPoint();
 118       IPC::Message* reply = IPC::SyncMessage::GenerateReply(&message);
 119       GpuCommandBufferMsg_InsertSyncPoint::WriteReplyParams(reply, sync_point);
 120       Send(reply);
 121       message_loop_->PostTask(FROM_HERE, base::Bind(
 122           &GpuChannelMessageFilter::InsertSyncPointOnMainThread,
 123           gpu_channel_,
 124           sync_point_manager_,
 125           message.routing_id(),
 126           sync_point));
 127       handled = true;
 128     }
 129     return handled;
 130   }
 131
 132   void MessageProcessed(uint64 messages_processed) {
 133     while (!pending_messages_.empty() &&
 134            pending_messages_.front().message_number <= messages_processed)
 135       pending_messages_.pop();
 136     UpdatePreemptionState();
 137   }
 138
 139   void SetPreemptingFlagAndSchedulingState(
 140       gpu::PreemptionFlag* preempting_flag,
 141       bool a_stub_is_descheduled) {
 142     preempting_flag_ = preempting_flag;
 143     a_stub_is_descheduled_ = a_stub_is_descheduled;
 144   }
 145
 146   void UpdateStubSchedulingState(bool a_stub_is_descheduled) {
 147     a_stub_is_descheduled_ = a_stub_is_descheduled;
 148     UpdatePreemptionState();
 149   }
 150
 151   bool Send(IPC::Message* message) {
 152     return channel_->Send(message);
 153   }
 154
 155  protected:
 156   virtual ~GpuChannelMessageFilter() {
 157     message_loop_->PostTask(FROM_HERE, base::Bind(
 158         &GpuChannelMessageFilter::DeleteWeakPtrOnMainThread, gpu_channel_));
 159   }
 160
 161  private:
 162   enum PreemptionState {
 163     // Either there's no other channel to preempt, there are no messages
 164     // pending processing, or we just finished preempting and have to wait
 165     // before preempting again.
 166     IDLE,
 167     // We are waiting kPreemptWaitTimeMs before checking if we should preempt.
 168     WAITING,
 169     // We can preempt whenever any IPC processing takes more than
 170     // kPreemptWaitTimeMs.
 171     CHECKING,
 172     // We are currently preempting (i.e. no stub is descheduled).
 173     PREEMPTING,
 174     // We would like to preempt, but some stub is descheduled.
 175     WOULD_PREEMPT_DESCHEDULED,
 176   };
 177
 178   PreemptionState preemption_state_;
 179
 180   // Maximum amount of time that we can spend in PREEMPTING.
 181   // It is reset when we transition to IDLE.
 182   base::TimeDelta max_preemption_time_;
 183
 184   struct PendingMessage {
 185     uint64 message_number;
 186     base::TimeTicks time_received;
 187
 188     explicit PendingMessage(uint64 message_number)
 189         : message_number(message_number),
 190           time_received(base::TimeTicks::Now()) {
 191     }
 192   };
 193
 194   void UpdatePreemptionState() {
 195     switch (preemption_state_) {
 196       case IDLE:
 197         if (preempting_flag_.get() && !pending_messages_.empty())
 198           TransitionToWaiting();
 199         break;
 200       case WAITING:
 201         // A timer will transition us to CHECKING.
 202         DCHECK(timer_.IsRunning());
 203         break;
 204       case CHECKING:
 205         if (!pending_messages_.empty()) {
 206           base::TimeDelta time_elapsed =
 207               base::TimeTicks::Now() - pending_messages_.front().time_received;
 208           if (time_elapsed.InMilliseconds() < kPreemptWaitTimeMs) {
 209             // Schedule another check for when the IPC may go long.
 210             timer_.Start(
 211                 FROM_HERE,
 212                 base::TimeDelta::FromMilliseconds(kPreemptWaitTimeMs) -
 213                     time_elapsed,
 214                 this, &GpuChannelMessageFilter::UpdatePreemptionState);
 215           } else {
 216             if (a_stub_is_descheduled_)
 217               TransitionToWouldPreemptDescheduled();
 218             else
 219               TransitionToPreempting();
 220           }
 221         }
 222         break;
 223       case PREEMPTING:
 224         // A TransitionToIdle() timer should always be running in this state.
 225         DCHECK(timer_.IsRunning());
 226         if (a_stub_is_descheduled_)
 227           TransitionToWouldPreemptDescheduled();
 228         else
 229           TransitionToIdleIfCaughtUp();
 230         break;
 231       case WOULD_PREEMPT_DESCHEDULED:
 232         // A TransitionToIdle() timer should never be running in this state.
 233         DCHECK(!timer_.IsRunning());
 234         if (!a_stub_is_descheduled_)
 235           TransitionToPreempting();
 236         else
 237           TransitionToIdleIfCaughtUp();
 238         break;
 239       default:
 240         NOTREACHED();
 241     }
 242   }
 243
 244   void TransitionToIdleIfCaughtUp() {
 245     DCHECK(preemption_state_ == PREEMPTING ||
 246            preemption_state_ == WOULD_PREEMPT_DESCHEDULED);
 247     if (pending_messages_.empty()) {
 248       TransitionToIdle();
 249     } else {
 250       base::TimeDelta time_elapsed =
 251           base::TimeTicks::Now() - pending_messages_.front().time_received;
 252       if (time_elapsed.InMilliseconds() < kStopPreemptThresholdMs)
 253         TransitionToIdle();
 254     }
 255   }
 256
 257   void TransitionToIdle() {
 258     DCHECK(preemption_state_ == PREEMPTING ||
 259            preemption_state_ == WOULD_PREEMPT_DESCHEDULED);
 260     // Stop any outstanding timer set to force us from PREEMPTING to IDLE.
 261     timer_.Stop();
 262
 263     preemption_state_ = IDLE;
 264     preempting_flag_->Reset();
 265     TRACE_COUNTER_ID1("gpu", "GpuChannel::Preempting", this, 0);
 266
 267     UpdatePreemptionState();
 268   }
 269
 270   void TransitionToWaiting() {
 271     DCHECK_EQ(preemption_state_, IDLE);
 272     DCHECK(!timer_.IsRunning());
 273
 274     preemption_state_ = WAITING;
 275     timer_.Start(
 276         FROM_HERE,
 277         base::TimeDelta::FromMilliseconds(kPreemptWaitTimeMs),
 278         this, &GpuChannelMessageFilter::TransitionToChecking);
 279   }
 280
 281   void TransitionToChecking() {
 282     DCHECK_EQ(preemption_state_, WAITING);
 283     DCHECK(!timer_.IsRunning());
 284
 285     preemption_state_ = CHECKING;
 286     max_preemption_time_ = base::TimeDelta::FromMilliseconds(kMaxPreemptTimeMs);
 287     UpdatePreemptionState();
 288   }
 289
 290   void TransitionToPreempting() {
 291     DCHECK(preemption_state_ == CHECKING ||
 292            preemption_state_ == WOULD_PREEMPT_DESCHEDULED);
 293     DCHECK(!a_stub_is_descheduled_);
 294
 295     // Stop any pending state update checks that we may have queued
 296     // while CHECKING.
 297     if (preemption_state_ == CHECKING)
 298       timer_.Stop();
 299
 300     preemption_state_ = PREEMPTING;
 301     preempting_flag_->Set();
 302     TRACE_COUNTER_ID1("gpu", "GpuChannel::Preempting", this, 1);
 303
 304     timer_.Start(
 305        FROM_HERE,
 306        max_preemption_time_,
 307        this, &GpuChannelMessageFilter::TransitionToIdle);
 308
 309     UpdatePreemptionState();
 310   }
 311
 312   void TransitionToWouldPreemptDescheduled() {
 313     DCHECK(preemption_state_ == CHECKING ||
 314            preemption_state_ == PREEMPTING);
 315     DCHECK(a_stub_is_descheduled_);
 316
 317     if (preemption_state_ == CHECKING) {
 318       // Stop any pending state update checks that we may have queued
 319       // while CHECKING.
 320       timer_.Stop();
 321     } else {
 322       // Stop any TransitionToIdle() timers that we may have queued
 323       // while PREEMPTING.
 324       timer_.Stop();
 325       max_preemption_time_ = timer_.desired_run_time() - base::TimeTicks::Now();
 326       if (max_preemption_time_ < base::TimeDelta()) {
 327         TransitionToIdle();
 328         return;
 329       }
 330     }
 331
 332     preemption_state_ = WOULD_PREEMPT_DESCHEDULED;
 333     preempting_flag_->Reset();
 334     TRACE_COUNTER_ID1("gpu", "GpuChannel::Preempting", this, 0);
 335
 336     UpdatePreemptionState();
 337   }
 338
 339   static void InsertSyncPointOnMainThread(
 340       base::WeakPtr<GpuChannel>* gpu_channel,
 341       scoped_refptr<SyncPointManager> manager,
 342       int32 routing_id,
 343       uint32 sync_point) {
 344     // This function must ensure that the sync point will be retired. Normally
 345     // we'll find the stub based on the routing ID, and associate the sync point
 346     // with it, but if that fails for any reason (channel or stub already
 347     // deleted, invalid routing id), we need to retire the sync point
 348     // immediately.
 349     if (gpu_channel->get()) {
 350       GpuCommandBufferStub* stub = gpu_channel->get()->LookupCommandBuffer(
 351           routing_id);
 352       if (stub) {
 353         stub->AddSyncPoint(sync_point);
 354         GpuCommandBufferMsg_RetireSyncPoint message(routing_id, sync_point);
 355         gpu_channel->get()->OnMessageReceived(message);
 356         return;
 357       } else {
 358         gpu_channel->get()->MessageProcessed();
 359       }
 360     }
 361     manager->RetireSyncPoint(sync_point);
 362   }
 363
 364   static void DeleteWeakPtrOnMainThread(
 365       base::WeakPtr<GpuChannel>* gpu_channel) {
 366     delete gpu_channel;
 367   }
 368
 369   // NOTE: this is a pointer to a weak pointer. It is never dereferenced on the
 370   // IO thread, it's only passed through - therefore the WeakPtr assumptions are
 371   // respected.
 372   base::WeakPtr<GpuChannel>* gpu_channel_;
 373   IPC::Channel* channel_;
 374   scoped_refptr<SyncPointManager> sync_point_manager_;
 375   scoped_refptr<base::MessageLoopProxy> message_loop_;
 376   scoped_refptr<gpu::PreemptionFlag> preempting_flag_;
 377
 378   std::queue<PendingMessage> pending_messages_;
 379
 380   // Count of the number of IPCs forwarded to the GpuChannel.
 381   uint64 messages_forwarded_to_channel_;
 382
 383   base::OneShotTimer<GpuChannelMessageFilter> timer_;
 384
 385   bool a_stub_is_descheduled_;
 386 };
 387
 388 GpuChannel::GpuChannel(GpuChannelManager* gpu_channel_manager,
 389                        GpuWatchdog* watchdog,
 390                        gfx::GLShareGroup* share_group,
 391                        gpu::gles2::MailboxManager* mailbox,
 392                        int client_id,
 393                        bool software)
 394     : gpu_channel_manager_(gpu_channel_manager),
 395       messages_processed_(0),
 396       client_id_(client_id),
 397       share_group_(share_group ? share_group : new gfx::GLShareGroup),
 398       mailbox_manager_(mailbox ? mailbox : new gpu::gles2::MailboxManager),
 399       image_manager_(new gpu::gles2::ImageManager),
 400       watchdog_(watchdog),
 401       software_(software),
 402       handle_messages_scheduled_(false),
 403       currently_processing_message_(NULL),
 404       weak_factory_(this),
 405       num_stubs_descheduled_(0) {
 406   DCHECK(gpu_channel_manager);
 407   DCHECK(client_id);
 408
 409   channel_id_ = IPC::Channel::GenerateVerifiedChannelID("gpu");
 410   const CommandLine* command_line = CommandLine::ForCurrentProcess();
 411   log_messages_ = command_line->HasSwitch(switches::kLogPluginMessages);
 412 }
 413
 414
 415 void GpuChannel::Init(base::MessageLoopProxy* io_message_loop,
 416                       base::WaitableEvent* shutdown_event) {
 417   DCHECK(!channel_.get());
 418
 419   // Map renderer ID to a (single) channel to that process.
 420   channel_.reset(new IPC::SyncChannel(
 421       channel_id_,
 422       IPC::Channel::MODE_SERVER,
 423       this,
 424       io_message_loop,
 425       false,
 426       shutdown_event));
 427
 428   base::WeakPtr<GpuChannel>* weak_ptr(new base::WeakPtr<GpuChannel>(
 429       weak_factory_.GetWeakPtr()));
 430
 431   filter_ = new GpuChannelMessageFilter(
 432       weak_ptr,
 433       gpu_channel_manager_->sync_point_manager(),
 434       base::MessageLoopProxy::current());
 435   io_message_loop_ = io_message_loop;
 436   channel_->AddFilter(filter_.get());
 437
 438   devtools_gpu_agent_.reset(new DevToolsGpuAgent(this));
 439 }
 440
 441 std::string GpuChannel::GetChannelName() {
 442   return channel_id_;
 443 }
 444
 445 #if defined(OS_POSIX)
 446 int GpuChannel::TakeRendererFileDescriptor() {
 447   if (!channel_) {
 448     NOTREACHED();
 449     return -1;
 450   }
 451   return channel_->TakeClientFileDescriptor();
 452 }
 453 #endif  // defined(OS_POSIX)
 454
 455 bool GpuChannel::OnMessageReceived(const IPC::Message& message) {
 456   if (log_messages_) {
 457     DVLOG(1) << "received message @" << &message << " on channel @" << this
 458              << " with type " << message.type();
 459   }
 460
 461   if (message.type() == GpuCommandBufferMsg_WaitForTokenInRange::ID ||
 462       message.type() == GpuCommandBufferMsg_WaitForGetOffsetInRange::ID) {
 463     // Move Wait commands to the head of the queue, so the renderer
 464     // doesn't have to wait any longer than necessary.
 465     deferred_messages_.push_front(new IPC::Message(message));
 466   } else {
 467     deferred_messages_.push_back(new IPC::Message(message));
 468   }
 469
 470   OnScheduled();
 471
 472   return true;
 473 }
 474
 475 void GpuChannel::OnChannelError() {
 476   gpu_channel_manager_->RemoveChannel(client_id_);
 477 }
 478
 479 bool GpuChannel::Send(IPC::Message* message) {
 480   // The GPU process must never send a synchronous IPC message to the renderer
 481   // process. This could result in deadlock.
 482   DCHECK(!message->is_sync());
 483   if (log_messages_) {
 484     DVLOG(1) << "sending message @" << message << " on channel @" << this
 485              << " with type " << message->type();
 486   }
 487
 488   if (!channel_) {
 489     delete message;
 490     return false;
 491   }
 492
 493   return channel_->Send(message);
 494 }
 495
 496 void GpuChannel::RequeueMessage() {
 497   DCHECK(currently_processing_message_);
 498   deferred_messages_.push_front(
 499       new IPC::Message(*currently_processing_message_));
 500   messages_processed_--;
 501   currently_processing_message_ = NULL;
 502 }
 503
 504 void GpuChannel::OnScheduled() {
 505   if (handle_messages_scheduled_)
 506     return;
 507   // Post a task to handle any deferred messages. The deferred message queue is
 508   // not emptied here, which ensures that OnMessageReceived will continue to
 509   // defer newly received messages until the ones in the queue have all been
 510   // handled by HandleMessage. HandleMessage is invoked as a
 511   // task to prevent reentrancy.
 512   base::MessageLoop::current()->PostTask(
 513       FROM_HERE,
 514       base::Bind(&GpuChannel::HandleMessage, weak_factory_.GetWeakPtr()));
 515   handle_messages_scheduled_ = true;
 516 }
 517
 518 void GpuChannel::StubSchedulingChanged(bool scheduled) {
 519   bool a_stub_was_descheduled = num_stubs_descheduled_ > 0;
 520   if (scheduled) {
 521     num_stubs_descheduled_--;
 522     OnScheduled();
 523   } else {
 524     num_stubs_descheduled_++;
 525   }
 526   DCHECK_LE(num_stubs_descheduled_, stubs_.size());
 527   bool a_stub_is_descheduled = num_stubs_descheduled_ > 0;
 528
 529   if (a_stub_is_descheduled != a_stub_was_descheduled) {
 530     if (preempting_flag_.get()) {
 531       io_message_loop_->PostTask(
 532           FROM_HERE,
 533           base::Bind(&GpuChannelMessageFilter::UpdateStubSchedulingState,
 534                      filter_,
 535                      a_stub_is_descheduled));
 536     }
 537   }
 538 }
 539
 540 bool GpuChannel::CreateViewCommandBuffer(
 541     const gfx::GLSurfaceHandle& window,
 542     int32 surface_id,
 543     const GPUCreateCommandBufferConfig& init_params,
 544     int32 route_id) {
 545   TRACE_EVENT1("gpu",
 546                "GpuChannel::CreateViewCommandBuffer",
 547                "surface_id",
 548                surface_id);
 549
 550   GpuCommandBufferStub* share_group = stubs_.Lookup(init_params.share_group_id);
 551
 552   // Virtualize compositor contexts on OS X to prevent performance regressions
 553   // when enabling FCM.
 554   // http://crbug.com/180463
 555   bool use_virtualized_gl_context = false;
 556 #if defined(OS_MACOSX)
 557   use_virtualized_gl_context = true;
 558 #endif
 559
 560   scoped_ptr<GpuCommandBufferStub> stub(
 561       new GpuCommandBufferStub(this,
 562                                share_group,
 563                                window,
 564                                mailbox_manager_.get(),
 565                                image_manager_.get(),
 566                                gfx::Size(),
 567                                disallowed_features_,
 568                                init_params.attribs,
 569                                init_params.gpu_preference,
 570                                use_virtualized_gl_context,
 571                                route_id,
 572                                surface_id,
 573                                watchdog_,
 574                                software_,
 575                                init_params.active_url));
 576   if (preempted_flag_.get())
 577     stub->SetPreemptByFlag(preempted_flag_);
 578   if (!router_.AddRoute(route_id, stub.get())) {
 579     DLOG(ERROR) << "GpuChannel::CreateViewCommandBuffer(): "
 580                    "failed to add route";
 581     return false;
 582   }
 583   stubs_.AddWithID(stub.release(), route_id);
 584   return true;
 585 }
 586
 587 GpuCommandBufferStub* GpuChannel::LookupCommandBuffer(int32 route_id) {
 588   return stubs_.Lookup(route_id);
 589 }
 590
 591 void GpuChannel::CreateImage(
 592     gfx::PluginWindowHandle window,
 593     int32 image_id,
 594     gfx::Size* size) {
 595   TRACE_EVENT1("gpu",
 596                "GpuChannel::CreateImage",
 597                "image_id",
 598                image_id);
 599
 600   *size = gfx::Size();
 601
 602   if (image_manager_->LookupImage(image_id)) {
 603     LOG(ERROR) << "CreateImage failed, image_id already in use.";
 604     return;
 605   }
 606
 607   scoped_refptr<gfx::GLImage> image = gfx::GLImage::CreateGLImage(window);
 608   if (!image.get())
 609     return;
 610
 611   image_manager_->AddImage(image.get(), image_id);
 612   *size = image->GetSize();
 613 }
 614
 615 void GpuChannel::DeleteImage(int32 image_id) {
 616   TRACE_EVENT1("gpu",
 617                "GpuChannel::DeleteImage",
 618                "image_id",
 619                image_id);
 620
 621   image_manager_->RemoveImage(image_id);
 622 }
 623
 624 void GpuChannel::LoseAllContexts() {
 625   gpu_channel_manager_->LoseAllContexts();
 626 }
 627
 628 void GpuChannel::MarkAllContextsLost() {
 629   for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
 630        !it.IsAtEnd(); it.Advance()) {
 631     it.GetCurrentValue()->MarkContextLost();
 632   }
 633 }
 634
 635 void GpuChannel::DestroySoon() {
 636   base::MessageLoop::current()->PostTask(
 637       FROM_HERE, base::Bind(&GpuChannel::OnDestroy, this));
 638 }
 639
 640 bool GpuChannel::AddRoute(int32 route_id, IPC::Listener* listener) {
 641   return router_.AddRoute(route_id, listener);
 642 }
 643
 644 void GpuChannel::RemoveRoute(int32 route_id) {
 645   router_.RemoveRoute(route_id);
 646 }
 647
 648 gpu::PreemptionFlag* GpuChannel::GetPreemptionFlag() {
 649   if (!preempting_flag_.get()) {
 650     preempting_flag_ = new gpu::PreemptionFlag;
 651     io_message_loop_->PostTask(
 652         FROM_HERE, base::Bind(
 653             &GpuChannelMessageFilter::SetPreemptingFlagAndSchedulingState,
 654             filter_, preempting_flag_, num_stubs_descheduled_ > 0));
 655   }
 656   return preempting_flag_.get();
 657 }
 658
 659 void GpuChannel::SetPreemptByFlag(
 660     scoped_refptr<gpu::PreemptionFlag> preempted_flag) {
 661   preempted_flag_ = preempted_flag;
 662
 663   for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
 664        !it.IsAtEnd(); it.Advance()) {
 665     it.GetCurrentValue()->SetPreemptByFlag(preempted_flag_);
 666   }
 667 }
 668
 669 GpuChannel::~GpuChannel() {
 670   if (preempting_flag_.get())
 671     preempting_flag_->Reset();
 672 }
 673
 674 void GpuChannel::OnDestroy() {
 675   TRACE_EVENT0("gpu", "GpuChannel::OnDestroy");
 676   gpu_channel_manager_->RemoveChannel(client_id_);
 677 }
 678
 679 bool GpuChannel::OnControlMessageReceived(const IPC::Message& msg) {
 680   bool handled = true;
 681   IPC_BEGIN_MESSAGE_MAP(GpuChannel, msg)
 682     IPC_MESSAGE_HANDLER(GpuChannelMsg_CreateOffscreenCommandBuffer,
 683                         OnCreateOffscreenCommandBuffer)
 684     IPC_MESSAGE_HANDLER(GpuChannelMsg_DestroyCommandBuffer,
 685                         OnDestroyCommandBuffer)
 686     IPC_MESSAGE_HANDLER(GpuChannelMsg_DevToolsStartEventsRecording,
 687                         OnDevToolsStartEventsRecording)
 688     IPC_MESSAGE_HANDLER(GpuChannelMsg_DevToolsStopEventsRecording,
 689                         OnDevToolsStopEventsRecording)
 690     IPC_MESSAGE_UNHANDLED(handled = false)
 691   IPC_END_MESSAGE_MAP()
 692   DCHECK(handled) << msg.type();
 693   return handled;
 694 }
 695
 696 void GpuChannel::HandleMessage() {
 697   handle_messages_scheduled_ = false;
 698   if (deferred_messages_.empty())
 699     return;
 700
 701   bool should_fast_track_ack = false;
 702   IPC::Message* m = deferred_messages_.front();
 703   GpuCommandBufferStub* stub = stubs_.Lookup(m->routing_id());
 704
 705   do {
 706     if (stub) {
 707       if (!stub->IsScheduled())
 708         return;
 709       if (stub->IsPreempted()) {
 710         OnScheduled();
 711         return;
 712       }
 713     }
 714
 715     scoped_ptr<IPC::Message> message(m);
 716     deferred_messages_.pop_front();
 717     bool message_processed = true;
 718
 719     currently_processing_message_ = message.get();
 720     bool result;
 721     if (message->routing_id() == MSG_ROUTING_CONTROL)
 722       result = OnControlMessageReceived(*message);
 723     else
 724       result = router_.RouteMessage(*message);
 725     currently_processing_message_ = NULL;
 726
 727     if (!result) {
 728       // Respond to sync messages even if router failed to route.
 729       if (message->is_sync()) {
 730         IPC::Message* reply = IPC::SyncMessage::GenerateReply(&*message);
 731         reply->set_reply_error();
 732         Send(reply);
 733       }
 734     } else {
 735       // If the command buffer becomes unscheduled as a result of handling the
 736       // message but still has more commands to process, synthesize an IPC
 737       // message to flush that command buffer.
 738       if (stub) {
 739         if (stub->HasUnprocessedCommands()) {
 740           deferred_messages_.push_front(new GpuCommandBufferMsg_Rescheduled(
 741               stub->route_id()));
 742           message_processed = false;
 743         }
 744       }
 745     }
 746     if (message_processed)
 747       MessageProcessed();
 748
 749     // We want the EchoACK following the SwapBuffers to be sent as close as
 750     // possible, avoiding scheduling other channels in the meantime.
 751     should_fast_track_ack = false;
 752     if (!deferred_messages_.empty()) {
 753       m = deferred_messages_.front();
 754       stub = stubs_.Lookup(m->routing_id());
 755       should_fast_track_ack =
 756           (m->type() == GpuCommandBufferMsg_Echo::ID) &&
 757           stub && stub->IsScheduled();
 758     }
 759   } while (should_fast_track_ack);
 760
 761   if (!deferred_messages_.empty()) {
 762     OnScheduled();
 763   }
 764 }
 765
 766 void GpuChannel::OnCreateOffscreenCommandBuffer(
 767     const gfx::Size& size,
 768     const GPUCreateCommandBufferConfig& init_params,
 769     int32 route_id,
 770     bool* succeeded) {
 771   TRACE_EVENT0("gpu", "GpuChannel::OnCreateOffscreenCommandBuffer");
 772   GpuCommandBufferStub* share_group = stubs_.Lookup(init_params.share_group_id);
 773
 774   scoped_ptr<GpuCommandBufferStub> stub(new GpuCommandBufferStub(
 775       this,
 776       share_group,
 777       gfx::GLSurfaceHandle(),
 778       mailbox_manager_.get(),
 779       image_manager_.get(),
 780       size,
 781       disallowed_features_,
 782       init_params.attribs,
 783       init_params.gpu_preference,
 784       false,
 785       route_id,
 786       0,
 787       watchdog_,
 788       software_,
 789       init_params.active_url));
 790   if (preempted_flag_.get())
 791     stub->SetPreemptByFlag(preempted_flag_);
 792   if (!router_.AddRoute(route_id, stub.get())) {
 793     DLOG(ERROR) << "GpuChannel::OnCreateOffscreenCommandBuffer(): "
 794                    "failed to add route";
 795     *succeeded = false;
 796     return;
 797   }
 798   stubs_.AddWithID(stub.release(), route_id);
 799   TRACE_EVENT1("gpu", "GpuChannel::OnCreateOffscreenCommandBuffer",
 800                "route_id", route_id);
 801   *succeeded = true;
 802 }
 803
 804 void GpuChannel::OnDestroyCommandBuffer(int32 route_id) {
 805   TRACE_EVENT1("gpu", "GpuChannel::OnDestroyCommandBuffer",
 806                "route_id", route_id);
 807
 808   GpuCommandBufferStub* stub = stubs_.Lookup(route_id);
 809   if (!stub)
 810     return;
 811   bool need_reschedule = (stub && !stub->IsScheduled());
 812   router_.RemoveRoute(route_id);
 813   stubs_.Remove(route_id);
 814   // In case the renderer is currently blocked waiting for a sync reply from the
 815   // stub, we need to make sure to reschedule the GpuChannel here.
 816   if (need_reschedule) {
 817     // This stub won't get a chance to reschedule, so update the count now.
 818     StubSchedulingChanged(true);
 819   }
 820 }
 821
 822 void GpuChannel::OnDevToolsStartEventsRecording(int32 route_id,
 823                                                 bool* succeeded) {
 824   *succeeded = devtools_gpu_agent_->StartEventsRecording(route_id);
 825 }
 826
 827 void GpuChannel::OnDevToolsStopEventsRecording() {
 828   devtools_gpu_agent_->StopEventsRecording();
 829 }
 830
 831 void GpuChannel::MessageProcessed() {
 832   messages_processed_++;
 833   if (preempting_flag_.get()) {
 834     io_message_loop_->PostTask(
 835         FROM_HERE,
 836         base::Bind(&GpuChannelMessageFilter::MessageProcessed,
 837                    filter_,
 838                    messages_processed_));
 839   }
 840 }
 841
 842 void GpuChannel::CacheShader(const std::string& key,
 843                              const std::string& shader) {
 844   gpu_channel_manager_->Send(
 845       new GpuHostMsg_CacheShader(client_id_, key, shader));
 846 }
 847
 848 void GpuChannel::AddFilter(IPC::MessageFilter* filter) {
 849   channel_->AddFilter(filter);
 850 }
 851
 852 void GpuChannel::RemoveFilter(IPC::MessageFilter* filter) {
 853   channel_->RemoveFilter(filter);
 854 }
 855
 856 uint64 GpuChannel::GetMemoryUsage() {
 857   uint64 size = 0;
 858   for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
 859        !it.IsAtEnd(); it.Advance()) {
 860     size += it.GetCurrentValue()->GetMemoryUsage();
 861   }
 862   return size;
 863 }
 864
 865 }  // namespace content