cc: Add new RasterWorkerPool interface.

cc/resources/pixel_buffer_raster_worker_pool.cc

+// Copyright 2013 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 "cc/resources/pixel_buffer_raster_worker_pool.h"
+
+#include "cc/resources/resource.h"
+
+namespace cc {
+
+namespace {
+
+class PixelBufferWorkerPoolTaskImpl : public internal::WorkerPoolTask {
+ public:
+  // First callback parameter is true when task was canceled. Second is
+  // true when upload is needed.
+  typedef base::Callback<void(bool, bool)> Reply;
+
+  PixelBufferWorkerPoolTaskImpl(internal::RasterWorkerPoolTask* task,
+                                TaskVector* dependencies,
+                                uint8_t* buffer,
+                                const Reply& reply)
+      : internal::WorkerPoolTask(dependencies),
+        task_(task),
+        buffer_(buffer),
+        reply_(reply),
+        needs_upload_(false) {
+  }
+
+  // Overridden from internal::WorkerPoolTask:
+  virtual void RunOnThread(unsigned thread_index) OVERRIDE {
+    needs_upload_ = task_->RunOnThread(buffer_, thread_index);
+  }
+  virtual void DispatchCompletionCallback() OVERRIDE {
+    DCHECK(HasFinishedRunning() || !needs_upload_);
+    reply_.Run(!HasFinishedRunning(), needs_upload_);
+  }
+
+ private:
+  virtual ~PixelBufferWorkerPoolTaskImpl() {}
+
+  scoped_refptr<internal::RasterWorkerPoolTask> task_;
+  uint8_t* buffer_;
+  const Reply reply_;
+  bool needs_upload_;
+};
+
+// If we raster too fast we become upload bound, and pending
+// uploads consume memory. For maximum upload throughput, we would
+// want to allow for upload_throughput * pipeline_time of pending
+// uploads, after which we are just wasting memory. Since we don't
+// know our upload throughput yet, this just caps our memory usage.
+#if defined(OS_ANDROID)
+// For reference, the Nexus10 can upload 1MB in about 2.5ms.
+// Assuming a three frame deep pipeline this implies ~20MB.
+const size_t kMaxPendingUploadBytes = 20 * 1024 * 1024;
+// TODO(epenner): We should remove this upload limit (crbug.com/176197)
+const size_t kMaxPendingUploads = 72;
+#else
+const size_t kMaxPendingUploadBytes = 100 * 1024 * 1024;
+const size_t kMaxPendingUploads = 1000;
+#endif
+
+}  // namespace
+
+PixelBufferRasterWorkerPool::PixelBufferRasterWorkerPool(
+    ResourceProvider* resource_provider,
+    size_t num_threads) : RasterWorkerPool(resource_provider, num_threads),
+                          bytes_pending_upload_(0),
+                          has_performed_uploads_since_last_flush_(false) {
+  // TODO(reveman): Remove WorkerPool client interface.
+  WorkerPool::SetClient(this);
+}
+
+PixelBufferRasterWorkerPool::~PixelBufferRasterWorkerPool() {
+  DCHECK_EQ(0u, pixel_buffer_tasks_.size());
+  DCHECK_EQ(0u, tasks_with_pending_upload_.size());
+}
+
+void PixelBufferRasterWorkerPool::Shutdown() {
+  RasterWorkerPool::Shutdown();
+  AbortPendingUploads();
+  for (TaskMap::iterator it = pixel_buffer_tasks_.begin();
+       it != pixel_buffer_tasks_.end(); ++it) {
+    internal::RasterWorkerPoolTask* task = it->first;
+    DCHECK(!it->second);
+
+    // Everything else has been canceled.
+    DidFinishRasterTask(task);
+  }
+  pixel_buffer_tasks_.clear();
+}
+
+void PixelBufferRasterWorkerPool::ScheduleTasks(RasterTask::Queue* queue) {
+  RasterWorkerPool::SetRasterTasks(queue);
+
+  // Build new pixel buffer task set.
+  TaskMap new_pixel_buffer_tasks;
+  for (RasterTask::Queue::TaskVector::iterator it = raster_tasks_.begin();
+       it != raster_tasks_.end(); ++it) {
+    internal::RasterWorkerPoolTask* task = *it;
+    DCHECK(new_pixel_buffer_tasks.find(task) == new_pixel_buffer_tasks.end());
+    DCHECK(!task->HasCompleted());
+
+    // Use existing pixel buffer task if available.
+    TaskMap::iterator pixel_buffer_it = pixel_buffer_tasks_.find(task);
+    if (pixel_buffer_it == pixel_buffer_tasks_.end()) {
+      new_pixel_buffer_tasks[task] = NULL;
+      continue;
+    }
+
+    new_pixel_buffer_tasks[task] = pixel_buffer_it->second;
+    pixel_buffer_tasks_.erase(task);
+  }
+
+  // Transfer active pixel buffer tasks to |new_pixel_buffer_tasks|
+  // and cancel any remaining tasks.
+  for (TaskMap::iterator it = pixel_buffer_tasks_.begin();
+       it != pixel_buffer_tasks_.end(); ++it) {
+    internal::RasterWorkerPoolTask* task = it->first;
+
+    // Move task to |new_pixel_buffer_tasks|
+    if (it->second) {
+      new_pixel_buffer_tasks[task] = it->second;
+      continue;
+    }
+
+    // Everything else can be canceled.
+    DidFinishRasterTask(task);
+  }
+
+  pixel_buffer_tasks_.swap(new_pixel_buffer_tasks);
+
+  ScheduleMoreTasks();
+}
+
+void PixelBufferRasterWorkerPool::CheckForCompletedTasks() {
+  while (!tasks_with_pending_upload_.empty()) {
+    internal::RasterWorkerPoolTask* task = tasks_with_pending_upload_.front();
+
+    // Uploads complete in the order they are issued.
+    if (!resource_provider_->DidSetPixelsComplete(task->resource()->id()))
+      break;
+
+    // It's now safe to release the pixel buffer and the shared memory.
+    resource_provider_->ReleasePixelBuffer(task->resource()->id());
+
+    task->DidRun();
+    DidFinishRasterTask(task);
+    pixel_buffer_tasks_.erase(task);
+
+    bytes_pending_upload_ -= task->resource()->bytes();
+    tasks_with_pending_upload_.pop_front();
+  }
+
+  ScheduleMoreTasks();
+}
+
+bool PixelBufferRasterWorkerPool::ForceUploadToComplete(
+    const RasterTask& raster_task) {
+  for (TaskDeque::iterator it = tasks_with_pending_upload_.begin();
+       it != tasks_with_pending_upload_.end(); ++it) {
+    internal::RasterWorkerPoolTask* task = *it;
+    if (task == raster_task.internal_) {
+      resource_provider_->ForceSetPixelsToComplete(task->resource()->id());
+      return true;
+    }
+  }
+
+  return false;
+}
+
+void PixelBufferRasterWorkerPool::
+    DidFinishDispatchingWorkerPoolCompletionCallbacks() {
+  // If a flush is needed, do it now before starting to dispatch more tasks.
+  if (has_performed_uploads_since_last_flush_) {
+    resource_provider_->ShallowFlushIfSupported();
+    has_performed_uploads_since_last_flush_ = false;
+  }
+
+  ScheduleMoreTasks();
+}
+
+bool PixelBufferRasterWorkerPool::CanScheduleRasterTask(
+    internal::RasterWorkerPoolTask* task) {
+  if (tasks_with_pending_upload_.size() >= kMaxPendingUploads)
+    return false;
+  size_t new_bytes_pending = bytes_pending_upload_;
+  new_bytes_pending += task->resource()->bytes();
+  return new_bytes_pending <= kMaxPendingUploadBytes;
+}
+
+void PixelBufferRasterWorkerPool::ScheduleMoreTasks() {
+  internal::WorkerPoolTask::TaskVector raster_tasks;
+
+  for (RasterTask::Queue::TaskVector::iterator it = raster_tasks_.begin();
+       it != raster_tasks_.end(); ++it) {
+    internal::RasterWorkerPoolTask* task = *it;
+
+    TaskMap::iterator pixel_buffer_it = pixel_buffer_tasks_.find(task);
+    if (pixel_buffer_it == pixel_buffer_tasks_.end())
+      continue;
+
+    scoped_refptr<internal::WorkerPoolTask> pixel_buffer_task(
+        pixel_buffer_it->second);
+    if (pixel_buffer_task) {
+      if (!pixel_buffer_task->HasCompleted())
+        raster_tasks.push_back(pixel_buffer_task);
+      continue;
+    }
+
+    if (!CanScheduleRasterTask(task))
+      break;
+
+    // Request a pixel buffer. This will reserve shared memory.
+    resource_provider_->AcquirePixelBuffer(task->resource()->id());
+
+    // MapPixelBuffer() returns NULL if context was lost at the time
+    // AcquirePixelBuffer() was called. For simplicity we still post
+    // a raster task that is essentially a noop in these situations.
+    uint8* buffer = resource_provider_->MapPixelBuffer(task->resource()->id());
+
+    // TODO(reveman): Avoid having to make a copy of dependencies.
+    internal::WorkerPoolTask::TaskVector dependencies = task->dependencies();
+    pixel_buffer_task = make_scoped_refptr(
+        new PixelBufferWorkerPoolTaskImpl(
+            task,
+            &dependencies,
+            buffer,
+            base::Bind(&PixelBufferRasterWorkerPool::OnRasterTaskCompleted,
+                       base::Unretained(this),
+                       make_scoped_refptr(task))));
+
+    pixel_buffer_tasks_[task] = pixel_buffer_task;
+    raster_tasks.push_back(pixel_buffer_task);
+  }
+
+  ScheduleRasterTasks(&raster_tasks);
+}
+
+void PixelBufferRasterWorkerPool::OnRasterTaskCompleted(
+    scoped_refptr<internal::RasterWorkerPoolTask> task,
+    bool was_canceled,
+    bool needs_upload) {
+  DCHECK(pixel_buffer_tasks_.find(task) != pixel_buffer_tasks_.end());
+
+  // Balanced with MapPixelBuffer() call in ScheduleMoreTasks().
+  resource_provider_->UnmapPixelBuffer(task->resource()->id());
+
+  if (!needs_upload) {
+    resource_provider_->ReleasePixelBuffer(task->resource()->id());
+    // No upload needed. Dispatch completion callback.
+    if (!was_canceled)
+      task->DidRun();
+
+    DidFinishRasterTask(task);
+    pixel_buffer_tasks_.erase(task);
+    return;
+  }
+
+  resource_provider_->BeginSetPixels(task->resource()->id());
+  has_performed_uploads_since_last_flush_ = true;
+
+  bytes_pending_upload_ += task->resource()->bytes();
+  tasks_with_pending_upload_.push_back(task);
+}
+
+void PixelBufferRasterWorkerPool::AbortPendingUploads() {
+  while (!tasks_with_pending_upload_.empty()) {
+    internal::RasterWorkerPoolTask* task = tasks_with_pending_upload_.front();
+
+    resource_provider_->AbortSetPixels(task->resource()->id());
+    resource_provider_->ReleasePixelBuffer(task->resource()->id());
+
+    // Need to run the reply callback even though task was aborted.
+    DidFinishRasterTask(task);
+    pixel_buffer_tasks_.erase(task);
+
+    bytes_pending_upload_ -= task->resource()->bytes();
+    tasks_with_pending_upload_.pop_front();
+  }
+}
+
+void PixelBufferRasterWorkerPool::DidFinishRasterTask(
+    internal::RasterWorkerPoolTask* task) {
+  task->DidComplete();
+  task->DispatchCompletionCallback();
+}
+
+}  // namespace cc