Re-land: cc: Use worker context for one-copy tile initialization.

cc/raster/one_copy_tile_task_worker_pool.cc

 // Copyright 2014 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/raster/one_copy_tile_task_worker_pool.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/strings/stringprintf.h"
+#include "base/sys_info.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/base/math_util.h"
 #include "cc/debug/traced_value.h"
 #include "cc/raster/raster_buffer.h"
 #include "cc/resources/platform_color.h"
-#include "cc/resources/resource_pool.h"
 #include "cc/resources/scoped_resource.h"
+#include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
-#include "ui/gfx/gpu_memory_buffer.h"
+#include "gpu/command_buffer/client/gpu_memory_buffer_manager.h"
 
 namespace cc {
 namespace {
 
 class RasterBufferImpl : public RasterBuffer {
  public:
   RasterBufferImpl(OneCopyTileTaskWorkerPool* worker_pool,
                    ResourceProvider* resource_provider,
-                   ResourcePool* resource_pool,
                    ResourceFormat resource_format,
-                   const Resource* output_resource,
+                   const Resource* resource,
                    uint64_t previous_content_id)
       : worker_pool_(worker_pool),
-        resource_provider_(resource_provider),
-        resource_pool_(resource_pool),
-        output_resource_(output_resource),
-        raster_content_id_(0),
-        sequence_(0) {
-    if (worker_pool->have_persistent_gpu_memory_buffers() &&
-        previous_content_id) {
-      raster_resource_ =
-          resource_pool->TryAcquireResourceWithContentId(previous_content_id);
-    }
-    if (raster_resource_) {
-      raster_content_id_ = previous_content_id;
-      DCHECK_EQ(resource_format, raster_resource_->format());
-      DCHECK_EQ(output_resource->size().ToString(),
-                raster_resource_->size().ToString());
-    } else {
-      raster_resource_ = resource_pool->AcquireResource(output_resource->size(),
-                                                        resource_format);
-    }
+        resource_(resource),
+        lock_(resource_provider, resource->id()),
+        previous_content_id_(previous_content_id) {}
 
-    lock_.reset(new ResourceProvider::ScopedWriteLockGpuMemoryBuffer(
-        resource_provider_, raster_resource_->id()));
-  }
-
-  ~RasterBufferImpl() override {
-    // Release write lock in case a copy was never scheduled.
-    lock_.reset();
-
-    // Make sure any scheduled copy operations are issued before we release the
-    // raster resource.
-    if (sequence_)
-      worker_pool_->AdvanceLastIssuedCopyTo(sequence_);
-
-    // Return resources to pool so they can be used by another RasterBuffer
-    // instance.
-    resource_pool_->ReleaseResource(raster_resource_.Pass(),
-                                    raster_content_id_);
-  }
+  ~RasterBufferImpl() override {}
 
   // Overridden from RasterBuffer:
   void Playback(const RasterSource* raster_source,
                 const gfx::Rect& raster_full_rect,
                 const gfx::Rect& raster_dirty_rect,
                 uint64_t new_content_id,
                 float scale) override {
-    // If there's a raster_content_id_, we are reusing a resource with that
-    // content id.
-    bool reusing_raster_resource = raster_content_id_ != 0;
-    sequence_ = worker_pool_->PlaybackAndScheduleCopyOnWorkerThread(
-        reusing_raster_resource, lock_.Pass(), raster_resource_.get(),
-        output_resource_, raster_source, raster_full_rect, raster_dirty_rect,
-        scale);
-    // Store the content id of the resource to return to the pool.
-    raster_content_id_ = new_content_id;
+    worker_pool_->PlaybackAndScheduleCopyOnWorkerThread(
+        resource_, &lock_, raster_source, raster_full_rect, raster_dirty_rect,
+        scale, previous_content_id_, new_content_id);
   }
 
  private:
   OneCopyTileTaskWorkerPool* worker_pool_;
-  ResourceProvider* resource_provider_;
-  ResourcePool* resource_pool_;
-  const Resource* output_resource_;
-  uint64_t raster_content_id_;
-  scoped_ptr<ScopedResource> raster_resource_;
-  scoped_ptr<ResourceProvider::ScopedWriteLockGpuMemoryBuffer> lock_;
-  CopySequenceNumber sequence_;
+  const Resource* resource_;
+  ResourceProvider::ScopedWriteLockGL lock_;
+  uint64_t previous_content_id_;
 
   DISALLOW_COPY_AND_ASSIGN(RasterBufferImpl);
 };
 
-// Number of in-flight copy operations to allow.
-const int kMaxCopyOperations = 32;
+// Default limit for number of staging buffers.
+const size_t kMaxDefaultStagingBuffers = 32;
 
-// Delay been checking for copy operations to complete.
-const int kCheckForCompletedCopyOperationsTickRateMs = 1;
+// Delay between checking for query result to be available.
+const int kCheckForQueryResultAvailableTickRateMs = 1;
 
-// Number of failed attempts to allow before we perform a check that will
-// wait for copy operations to complete if needed.
-const int kFailedAttemptsBeforeWaitIfNeeded = 256;
+// Number of attempts to allow before we perform a check that will wait for
+// query to complete.
+const int kMaxCheckForQueryResultAvailableAttempts = 256;
 
 // 4MiB is the size of 4 512x512 tiles, which has proven to be a good
 // default batch size for copy operations.
 const int kMaxBytesPerCopyOperation = 1024 * 1024 * 4;
 
+// Delay before a staging buffer might be released.
+const int kStagingBufferExpirationDelayMs = 1000;
+
+bool CheckForQueryResult(gpu::gles2::GLES2Interface* gl, unsigned query_id) {
+  GLuint complete = 1;
+  gl->GetQueryObjectuivEXT(query_id, GL_QUERY_RESULT_AVAILABLE_EXT, &complete);
+  return complete;
+}
+
+void WaitForQueryResult(gpu::gles2::GLES2Interface* gl, unsigned query_id) {

[vmpstr, 2015/07/22 23:38:52]

This should probably return a bool?

[reveman, 2015/07/23 05:35:05]

Not sure what that would be for. This function can't fail.

+  TRACE_EVENT0("cc", "WaitForQueryResult");
+
+  int attempts_left = kMaxCheckForQueryResultAvailableAttempts;
+  while (attempts_left--) {
+    if (CheckForQueryResult(gl, query_id))
+      break;
+
+    base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(
+        kCheckForQueryResultAvailableTickRateMs));
+  }
+
+  unsigned result = 0;
+  gl->GetQueryObjectuivEXT(query_id, GL_QUERY_RESULT_EXT, &result);

[vmpstr, 2015/07/22 23:38:52]

Is this safe to call if we run out of attempts? If so, what's the behavior?

[reveman, 2015/07/23 05:35:05]

Yes, it's always safe to query the result but there's no guarantee that the
GLES2Implementation will do anything smarter than calling glFinish and we'd like
to avoid that if possible. If checking has failed too many times we just query
the result and let GLES2Implementation handle it as that allows us to detect
driver bugs.

The plan is to improve this code by using gl->SignalQuery and allow the GPU
service to notify the child process as soon as the query has passed. This will
also allow the GPU service to poll for query results less frequently as it will
know if a compositor is blocking on a query result.

+}
+
 }  // namespace
 
-OneCopyTileTaskWorkerPool::CopyOperation::CopyOperation(
-    scoped_ptr<ResourceProvider::ScopedWriteLockGpuMemoryBuffer> src_write_lock,
-    const Resource* src,
-    const Resource* dst,
-    const gfx::Rect& rect)
-    : src_write_lock(src_write_lock.Pass()), src(src), dst(dst), rect(rect) {
+OneCopyTileTaskWorkerPool::StagingBuffer::StagingBuffer(const gfx::Size& size)
+    : size(size), texture_id(0), image_id(0), query_id(0), content_id(0) {}
+
+OneCopyTileTaskWorkerPool::StagingBuffer::~StagingBuffer() {
+  DCHECK_EQ(texture_id, 0u);
+  DCHECK_EQ(image_id, 0u);
+  DCHECK_EQ(query_id, 0u);
 }
 
-OneCopyTileTaskWorkerPool::CopyOperation::~CopyOperation() {
+void OneCopyTileTaskWorkerPool::StagingBuffer::DestroyGLResources(
+    gpu::gles2::GLES2Interface* gl) {
+  if (query_id) {
+    gl->DeleteQueriesEXT(1, &query_id);
+    query_id = 0;
+  }
+  if (image_id) {
+    gl->DestroyImageCHROMIUM(image_id);
+    image_id = 0;
+  }
+  if (texture_id) {
+    gl->DeleteTextures(1, &texture_id);
+    texture_id = 0;
+  }
+}
+
+void OneCopyTileTaskWorkerPool::StagingBuffer::OnMemoryDump(
+    base::trace_event::ProcessMemoryDump* pmd,
+    ResourceFormat format) const {
+  if (!gpu_memory_buffer)
+    return;
+
+  gfx::GpuMemoryBufferId buffer_id = gpu_memory_buffer->GetId();
+  std::string buffer_dump_name =
+      base::StringPrintf("gpumemorybuffer/buffer_%d", buffer_id);
+  base::trace_event::MemoryAllocatorDump* buffer_dump =
+      pmd->CreateAllocatorDump(buffer_dump_name);
+
+  size_t buffer_size_in_bytes =
+      Resource::UncheckedMemorySizeBytes(size, format);
+  buffer_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
+                         base::trace_event::MemoryAllocatorDump::kUnitsBytes,
+                         static_cast<uint64_t>(buffer_size_in_bytes));
+
+  // Emit an ownership edge towards a global allocator dump node.
+  const uint64 tracing_process_id =
+      base::trace_event::MemoryDumpManager::GetInstance()->tracing_process_id();
+  base::trace_event::MemoryAllocatorDumpGuid shared_buffer_guid =
+      gfx::GetGpuMemoryBufferGUIDForTracing(tracing_process_id, buffer_id);
+  pmd->CreateSharedGlobalAllocatorDump(shared_buffer_guid);
+
+  // By creating an edge with a higher |importance| (w.r.t. browser-side dumps)
+  // the tracing UI will account the effective size of the buffer to the child.
+  const int kImportance = 2;
+  pmd->AddOwnershipEdge(buffer_dump->guid(), shared_buffer_guid, kImportance);
 }
 
 // static
 scoped_ptr<TileTaskWorkerPool> OneCopyTileTaskWorkerPool::Create(
     base::SequencedTaskRunner* task_runner,
     TaskGraphRunner* task_graph_runner,
     ContextProvider* context_provider,
     ResourceProvider* resource_provider,
-    ResourcePool* resource_pool,
     int max_copy_texture_chromium_size,
-    bool have_persistent_gpu_memory_buffers) {
+    bool use_persistent_gpu_memory_buffers,
+    unsigned image_target) {
   return make_scoped_ptr<TileTaskWorkerPool>(new OneCopyTileTaskWorkerPool(
-      task_runner, task_graph_runner, context_provider, resource_provider,
-      resource_pool, max_copy_texture_chromium_size,
-      have_persistent_gpu_memory_buffers));
+      task_runner, task_graph_runner, resource_provider,
+      max_copy_texture_chromium_size, use_persistent_gpu_memory_buffers,
+      image_target));
 }
 
 OneCopyTileTaskWorkerPool::OneCopyTileTaskWorkerPool(
     base::SequencedTaskRunner* task_runner,
     TaskGraphRunner* task_graph_runner,
-    ContextProvider* context_provider,
     ResourceProvider* resource_provider,
-    ResourcePool* resource_pool,
     int max_copy_texture_chromium_size,
-    bool have_persistent_gpu_memory_buffers)
+    bool use_persistent_gpu_memory_buffers,
+    unsigned image_target)
     : task_runner_(task_runner),
       task_graph_runner_(task_graph_runner),
       namespace_token_(task_graph_runner->GetNamespaceToken()),
-      context_provider_(context_provider),
       resource_provider_(resource_provider),
-      resource_pool_(resource_pool),
       max_bytes_per_copy_operation_(
           max_copy_texture_chromium_size
               ? std::min(kMaxBytesPerCopyOperation,
                          max_copy_texture_chromium_size)
               : kMaxBytesPerCopyOperation),
-      have_persistent_gpu_memory_buffers_(have_persistent_gpu_memory_buffers),
-      last_issued_copy_operation_(0),
-      last_flushed_copy_operation_(0),
-      lock_(),
-      copy_operation_count_cv_(&lock_),
+      use_persistent_gpu_memory_buffers_(use_persistent_gpu_memory_buffers),
+      image_target_(image_target),
       bytes_scheduled_since_last_flush_(0),
-      issued_copy_operation_count_(0),
-      next_copy_operation_sequence_(1),
-      check_for_completed_copy_operations_pending_(false),
-      shutdown_(false),
+      max_staging_buffers_(
+          base::SysInfo::IsLowEndDevice()
+              ?
+              // Use 1/4th of staging buffers on low-end devices.
+              kMaxDefaultStagingBuffers / 4
+              : kMaxDefaultStagingBuffers),

[reveman, 2015/07/22 22:39:15]

Note: this reduction in staging buffer usage is supposed to match the logic in
render_widget.cc where we set the mapped_memory_reclaim_limit. I'm a bit less
aggressive here as we're much better at releasing staging buffers when they are
no longer in use. Some logic for low-end devices is still needed to not increase
spikes in memory usage when switching from async uploads.

[vmpstr, 2015/07/22 23:38:52]

This should probably be a setting in layer_tree_settings that we can pass to
OneCopyTileTaskWorkerPool at construction time and set to an appropriate value
for low end devices in render_widget_compositor. Wdyt?

I'd like to avoid IsLowEndDevice checks in cc

[reveman, 2015/07/23 05:35:05]

Done.

+      staging_buffer_expiration_delay_(
+          base::TimeDelta::FromMilliseconds(kStagingBufferExpirationDelayMs)),
+      reduce_memory_usage_pending_(false),
       weak_ptr_factory_(this),
       task_set_finished_weak_ptr_factory_(this) {
-  DCHECK(context_provider_);
+  base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
+      this, base::ThreadTaskRunnerHandle::Get());
+  reduce_memory_usage_callback_ =
+      base::Bind(&OneCopyTileTaskWorkerPool::ReduceMemoryUsage,
+                 weak_ptr_factory_.GetWeakPtr());
 }
 
 OneCopyTileTaskWorkerPool::~OneCopyTileTaskWorkerPool() {
-  DCHECK_EQ(pending_copy_operations_.size(), 0u);
+  base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
+      this);
 }
 
 TileTaskRunner* OneCopyTileTaskWorkerPool::AsTileTaskRunner() {
   return this;
 }
 
 void OneCopyTileTaskWorkerPool::SetClient(TileTaskRunnerClient* client) {
   client_ = client;
 }
 
 void OneCopyTileTaskWorkerPool::Shutdown() {
   TRACE_EVENT0("cc", "OneCopyTileTaskWorkerPool::Shutdown");
 
-  {
-    base::AutoLock lock(lock_);
-
-    shutdown_ = true;
-    copy_operation_count_cv_.Signal();
-  }
-
   TaskGraph empty;
   task_graph_runner_->ScheduleTasks(namespace_token_, &empty);
   task_graph_runner_->WaitForTasksToFinishRunning(namespace_token_);
+
+  base::AutoLock lock(lock_);
+
+  if (buffers_.empty())
+    return;
+
+  ReleaseBuffersNotUsedSince(base::TimeTicks() + base::TimeDelta::Max());
 }
 
 void OneCopyTileTaskWorkerPool::ScheduleTasks(TileTaskQueue* queue) {
   TRACE_EVENT0("cc", "OneCopyTileTaskWorkerPool::ScheduleTasks");
 
-#if DCHECK_IS_ON()
-  {
-    base::AutoLock lock(lock_);
-    DCHECK(!shutdown_);
-  }
-#endif
-
   if (tasks_pending_.none())
     TRACE_EVENT_ASYNC_BEGIN0("cc", "ScheduledTasks", this);
 
   // Mark all task sets as pending.
   tasks_pending_.set();
 
   size_t priority = kTileTaskPriorityBase;
 
   graph_.Reset();
 
   // Cancel existing OnTaskSetFinished callbacks.
   task_set_finished_weak_ptr_factory_.InvalidateWeakPtrs();
 
   scoped_refptr<TileTask> new_task_set_finished_tasks[kNumberOfTaskSets];
 
   size_t task_count[kNumberOfTaskSets] = {0};
 
   for (TaskSet task_set = 0; task_set < kNumberOfTaskSets; ++task_set) {
     new_task_set_finished_tasks[task_set] = CreateTaskSetFinishedTask(
         task_runner_.get(),
         base::Bind(&OneCopyTileTaskWorkerPool::OnTaskSetFinished,
                    task_set_finished_weak_ptr_factory_.GetWeakPtr(), task_set));
   }
 
-  resource_pool_->CheckBusyResources(false);
-
   for (TileTaskQueue::Item::Vector::const_iterator it = queue->items.begin();
        it != queue->items.end(); ++it) {
     const TileTaskQueue::Item& item = *it;
     RasterTask* task = item.task;
     DCHECK(!task->HasCompleted());
 
     for (TaskSet task_set = 0; task_set < kNumberOfTaskSets; ++task_set) {
       if (!item.task_sets[task_set])
         continue;
 
       ++task_count[task_set];
 
       graph_.edges.push_back(
           TaskGraph::Edge(task, new_task_set_finished_tasks[task_set].get()));
     }
 
     InsertNodesForRasterTask(&graph_, task, task->dependencies(), priority++);
   }
 
   for (TaskSet task_set = 0; task_set < kNumberOfTaskSets; ++task_set) {
     InsertNodeForTask(&graph_, new_task_set_finished_tasks[task_set].get(),
                       kTaskSetFinishedTaskPriorityBase + task_set,
                       task_count[task_set]);
   }
 
   ScheduleTasksOnOriginThread(this, &graph_);
+
+  // Barrier to sync any new resources to the worker context.
+  resource_provider_->output_surface()
+      ->context_provider()
+      ->ContextGL()
+      ->OrderingBarrierCHROMIUM();
+
   task_graph_runner_->ScheduleTasks(namespace_token_, &graph_);
 
   std::copy(new_task_set_finished_tasks,
             new_task_set_finished_tasks + kNumberOfTaskSets,
             task_set_finished_tasks_);
 
-  resource_pool_->ReduceResourceUsage();
-
   TRACE_EVENT_ASYNC_STEP_INTO1("cc", "ScheduledTasks", this, "running", "state",
                                StateAsValue());
 }
 
 void OneCopyTileTaskWorkerPool::CheckForCompletedTasks() {
   TRACE_EVENT0("cc", "OneCopyTileTaskWorkerPool::CheckForCompletedTasks");
 
   task_graph_runner_->CollectCompletedTasks(namespace_token_,
                                             &completed_tasks_);
 
   for (Task::Vector::const_iterator it = completed_tasks_.begin();
        it != completed_tasks_.end(); ++it) {
     TileTask* task = static_cast<TileTask*>(it->get());
 
     task->WillComplete();
     task->CompleteOnOriginThread(this);
     task->DidComplete();
 
     task->RunReplyOnOriginThread();
   }
   completed_tasks_.clear();
 }
 
 ResourceFormat OneCopyTileTaskWorkerPool::GetResourceFormat() const {
-  return resource_provider_->best_texture_format();
+  return resource_provider_->memory_efficient_texture_format();

[vmpstr, 2015/07/22 23:38:52]

Why the change here?

[reveman, 2015/07/23 05:35:05]

This was preventing us from using RGBA_4444 on some low-end devices, which is
the main reason for why we had a memory regression when switching to one-copy on
some Android devices. I can move this change to a separate patch if you like? I
ended up including it here as I've been running tests to verify all memory usage
improvements this patch provides and this is an important part of that.

 }
 
 bool OneCopyTileTaskWorkerPool::GetResourceRequiresSwizzle() const {
   return !PlatformColor::SameComponentOrder(GetResourceFormat());
 }
 
 scoped_ptr<RasterBuffer> OneCopyTileTaskWorkerPool::AcquireBufferForRaster(
     const Resource* resource,
     uint64_t resource_content_id,
     uint64_t previous_content_id) {
   // TODO(danakj): If resource_content_id != 0, we only need to copy/upload
   // the dirty rect.
-  DCHECK_EQ(resource->format(), resource_provider_->best_texture_format());
-  return make_scoped_ptr<RasterBuffer>(
-      new RasterBufferImpl(this, resource_provider_, resource_pool_,
-                           resource_provider_->best_texture_format(), resource,
-                           previous_content_id));
+  DCHECK_EQ(resource->format(),
+            resource_provider_->memory_efficient_texture_format());
+  return make_scoped_ptr<RasterBuffer>(new RasterBufferImpl(
+      this, resource_provider_,
+      resource_provider_->memory_efficient_texture_format(), resource,
+      previous_content_id));
 }
 
 void OneCopyTileTaskWorkerPool::ReleaseBufferForRaster(
     scoped_ptr<RasterBuffer> buffer) {
   // Nothing to do here. RasterBufferImpl destructor cleans up after itself.
 }
 
-CopySequenceNumber
-OneCopyTileTaskWorkerPool::PlaybackAndScheduleCopyOnWorkerThread(
-    bool reusing_raster_resource,
-    scoped_ptr<ResourceProvider::ScopedWriteLockGpuMemoryBuffer>
-        raster_resource_write_lock,
-    const Resource* raster_resource,
-    const Resource* output_resource,
+void OneCopyTileTaskWorkerPool::PlaybackAndScheduleCopyOnWorkerThread(
+    const Resource* resource,
+    const ResourceProvider::ScopedWriteLockGL* resource_lock,
     const RasterSource* raster_source,
     const gfx::Rect& raster_full_rect,
     const gfx::Rect& raster_dirty_rect,
-    float scale) {
-  gfx::GpuMemoryBuffer* gpu_memory_buffer =
-      raster_resource_write_lock->GetGpuMemoryBuffer();
-  if (gpu_memory_buffer) {
-    void* data = NULL;
-    bool rv = gpu_memory_buffer->Map(&data);
-    DCHECK(rv);
-    int stride;
-    gpu_memory_buffer->GetStride(&stride);
-    // TileTaskWorkerPool::PlaybackToMemory only supports unsigned strides.
-    DCHECK_GE(stride, 0);
+    float scale,
+    uint64_t previous_content_id,
+    uint64_t new_content_id) {
+  base::AutoLock lock(lock_);
+
+  scoped_ptr<StagingBuffer> staging_buffer;
+
+  ContextProvider* context_provider =
+      resource_provider_->output_surface()->worker_context_provider();
+  DCHECK(context_provider);
+
+  {

[vmpstr, 2015/07/22 23:38:52]

I think each of these { } can easily be a separate function :P

+    ContextProvider::ScopedContextGL scoped_context(context_provider);
+
+    gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
+    DCHECK(gl);
+
+    // Check if any busy buffers have become available.
+    if (resource_provider_->use_sync_query()) {
+      while (!busy_buffers_.empty()) {
+        if (!CheckForQueryResult(gl, busy_buffers_.front()->query_id))
+          break;
+
+        free_buffers_.push_back(busy_buffers_.take_front());
+      }
+    }
+
+    // Wait for number of non-free buffers to become less than the limit.

[vmpstr, 2015/07/22 23:38:52]

what's the relationship between busy_buffers_ buffers_ and free_buffers_? Like
non-free buffer is a busy_buffer? or not necessarily?

[reveman, 2015/07/23 05:35:05]

A buffer can be in one of three states. 1) free, 2) used for raster, 3) busy.
|buffers_| contains all buffers independent of state. Ownership of the buffer is
either in |free_buffers_|, in |busy_buffers_| or the local variable in this
function.

+    while ((buffers_.size() - free_buffers_.size()) >= max_staging_buffers_) {
+      // Stop when there are no more busy buffers to wait for.
+      if (busy_buffers_.empty())
+        break;
+
+      if (resource_provider_->use_sync_query()) {
+        WaitForQueryResult(gl, busy_buffers_.front()->query_id);

[vmpstr, 2015/07/22 23:38:52]

If we ran out of attempts, can we still consider this a free buffer?

[reveman, 2015/07/23 05:35:05]

The attempts are just an internal detail to avoid a call to glFinish.
WaitForQueryResult does what the name describes, it waits for the query result
and will not return until it's available.

+        free_buffers_.push_back(busy_buffers_.take_front());
+      } else {
+        // Fall-back to glFinish if CHROMIUM_sync_query is not available.
+        gl->Finish();
+        while (!busy_buffers_.empty())
+          free_buffers_.push_back(busy_buffers_.take_front());
+      }
+    }
+
+    // Find a staging buffer that allows us to perform partial raster when
+    // using persistent GpuMemoryBuffers.
+    if (use_persistent_gpu_memory_buffers_ && previous_content_id) {
+      StagingBufferDeque::iterator it =
+          std::find_if(free_buffers_.begin(), free_buffers_.end(),
+                       [previous_content_id](const StagingBuffer* buffer) {
+                         return buffer->content_id == previous_content_id;
+                       });
+      if (it != free_buffers_.end())
+        staging_buffer = free_buffers_.take(it);
+    }
+
+    // Find staging buffer of correct size.
+    if (!staging_buffer) {
+      StagingBufferDeque::iterator it =
+          std::find_if(free_buffers_.begin(), free_buffers_.end(),
+                       [resource](const StagingBuffer* buffer) {
+                         return buffer->size == resource->size();
+                       });
+      if (it != free_buffers_.end())
+        staging_buffer = free_buffers_.take(it);
+    }
+
+    // Create new staging buffer if necessary.
+    if (!staging_buffer) {
+      staging_buffer = make_scoped_ptr(new StagingBuffer(resource->size()));
+      buffers_.insert(staging_buffer.get());
+    }
+
+    // Release enough free buffers to stay within the limit.
+    while (buffers_.size() > max_staging_buffers_) {
+      if (free_buffers_.empty())
+        break;
+
+      free_buffers_.front()->DestroyGLResources(gl);
+      buffers_.erase(free_buffers_.front());
+      free_buffers_.take_front();
+    }
+  }
+
+  {
+    base::AutoUnlock unlock(lock_);
+
+    // Allocate GpuMemoryBuffer if necessary.
+    DCHECK(staging_buffer);
+    if (!staging_buffer->gpu_memory_buffer) {
+      staging_buffer->gpu_memory_buffer =
+          resource_provider_->gpu_memory_buffer_manager()
+              ->AllocateGpuMemoryBuffer(
+                  staging_buffer->size,
+                  ToGpuMemoryBufferFormat(
+                      resource_provider_->memory_efficient_texture_format()),
+                  use_persistent_gpu_memory_buffers_
+                      ? gfx::GpuMemoryBuffer::PERSISTENT_MAP
+                      : gfx::GpuMemoryBuffer::MAP);
+    }
 
     gfx::Rect playback_rect = raster_full_rect;
-    if (reusing_raster_resource) {
-      playback_rect.Intersect(raster_dirty_rect);
-    }
-    DCHECK(!playback_rect.IsEmpty())
-        << "Why are we rastering a tile that's not dirty?";
-    TileTaskWorkerPool::PlaybackToMemory(
-        data, raster_resource->format(), raster_resource->size(),
-        static_cast<size_t>(stride), raster_source, raster_full_rect,
-        playback_rect, scale);
-    gpu_memory_buffer->Unmap();
-  }
-
+    if (use_persistent_gpu_memory_buffers_ && previous_content_id) {
+      // Reduce playback rect to dirty region if the content id of the staging
+      // buffer matches the prevous content id.
+      if (previous_content_id == staging_buffer->content_id)
+        playback_rect.Intersect(raster_dirty_rect);
+    }
+
+    if (staging_buffer->gpu_memory_buffer) {
+      void* data = NULL;

[vmpstr, 2015/07/22 23:38:52]

nullptr

[reveman, 2015/07/23 05:35:05]

Done.

+      bool rv = staging_buffer->gpu_memory_buffer->Map(&data);
+      DCHECK(rv);
+      int stride;
+      staging_buffer->gpu_memory_buffer->GetStride(&stride);
+      // TileTaskWorkerPool::PlaybackToMemory only supports unsigned strides.
+      DCHECK_GE(stride, 0);
+
+      DCHECK(!playback_rect.IsEmpty())
+          << "Why are we rastering a tile that's not dirty?";
+      TileTaskWorkerPool::PlaybackToMemory(
+          data, resource_provider_->memory_efficient_texture_format(),
+          staging_buffer->size, static_cast<size_t>(stride), raster_source,
+          raster_full_rect, playback_rect, scale);
+      staging_buffer->gpu_memory_buffer->Unmap();
+      staging_buffer->content_id = new_content_id;
+    }
+  }
+
+  {
+    ContextProvider::ScopedContextGL scoped_context(context_provider);
+
+    gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
+    DCHECK(gl);
+
+    if (!staging_buffer->texture_id) {
+      gl->GenTextures(1, &staging_buffer->texture_id);
+      gl->BindTexture(image_target_, staging_buffer->texture_id);
+      gl->TexParameteri(image_target_, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+      gl->TexParameteri(image_target_, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+      gl->TexParameteri(image_target_, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+      gl->TexParameteri(image_target_, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+      if (staging_buffer->gpu_memory_buffer) {
+        DCHECK(!staging_buffer->image_id);
+        staging_buffer->image_id = gl->CreateImageCHROMIUM(
+            staging_buffer->gpu_memory_buffer->AsClientBuffer(),
+            staging_buffer->size.width(), staging_buffer->size.height(),
+            GLInternalFormat(
+                resource_provider_->memory_efficient_texture_format()));
+        gl->BindTexImage2DCHROMIUM(image_target_, staging_buffer->image_id);
+      } else {
+        gl->BindTexture(image_target_, staging_buffer->texture_id);
+        gl->ReleaseTexImage2DCHROMIUM(image_target_, staging_buffer->image_id);
+        gl->BindTexImage2DCHROMIUM(image_target_, staging_buffer->image_id);
+      }
+    }
+
+    if (resource_provider_->use_sync_query()) {
+      if (!staging_buffer->query_id)
+        gl->GenQueriesEXT(1, &staging_buffer->query_id);
+
+#if defined(OS_CHROMEOS)
+      // TODO(reveman): This avoids a performance problem on some ChromeOS
+      // devices. This needs to be removed to support native GpuMemoryBuffer
+      // implementations. crbug.com/436314
+      gl->BeginQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM, staging_buffer->query_id);
+#else
+      gl->BeginQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM,
+                        staging_buffer->query_id);
+#endif
+    }
+
+    int bytes_per_row =
+        (BitsPerPixel(resource_provider_->memory_efficient_texture_format()) *
+         resource->size().width()) /
+        8;
+    int chunk_size_in_rows =
+        std::max(1, max_bytes_per_copy_operation_ / bytes_per_row);
+    // Align chunk size to 4. Required to support compressed texture formats.
+    chunk_size_in_rows = MathUtil::RoundUp(chunk_size_in_rows, 4);
+    int y = 0;
+    int height = resource->size().height();
+    while (y < height) {
+      // Copy at most |chunk_size_in_rows|.
+      int rows_to_copy = std::min(chunk_size_in_rows, height - y);
+      DCHECK_GT(rows_to_copy, 0);
+
+      gl->CopySubTextureCHROMIUM(GL_TEXTURE_2D, staging_buffer->texture_id,
+                                 resource_lock->texture_id(), 0, y, 0, y,
+                                 resource->size().width(), rows_to_copy, false,
+                                 false, false);
+      y += rows_to_copy;
+
+      // Increment |bytes_scheduled_since_last_flush_| by the amount of memory
+      // used for this copy operation.
+      bytes_scheduled_since_last_flush_ += rows_to_copy * bytes_per_row;
+
+      if (bytes_scheduled_since_last_flush_ >= max_bytes_per_copy_operation_) {
+        gl->ShallowFlushCHROMIUM();
+        bytes_scheduled_since_last_flush_ = 0;
+      }
+    }
+
+    if (resource_provider_->use_sync_query()) {
+#if defined(OS_CHROMEOS)
+      gl->EndQueryEXT(GL_COMMANDS_ISSUED_CHROMIUM);
+#else
+      gl->EndQueryEXT(GL_COMMANDS_COMPLETED_CHROMIUM);
+#endif
+    }
+
+    // Barrier to sync worker context output to cc context.
+    gl->OrderingBarrierCHROMIUM();
+  }
+
+  staging_buffer->last_usage = base::TimeTicks::Now();
+  busy_buffers_.push_back(staging_buffer.Pass());
+
+  ScheduleReduceMemoryUsage();
+}
+
+bool OneCopyTileTaskWorkerPool::OnMemoryDump(
+    base::trace_event::ProcessMemoryDump* pmd) {
   base::AutoLock lock(lock_);
 
-  CopySequenceNumber sequence = 0;
-  int bytes_per_row = (BitsPerPixel(raster_resource->format()) *
-                       raster_resource->size().width()) /
-                      8;
-  int chunk_size_in_rows =
-      std::max(1, max_bytes_per_copy_operation_ / bytes_per_row);
-  // Align chunk size to 4. Required to support compressed texture formats.
-  chunk_size_in_rows = MathUtil::RoundUp(chunk_size_in_rows, 4);
-  int y = 0;
-  int height = raster_resource->size().height();
-  while (y < height) {
-    int failed_attempts = 0;
-    while ((pending_copy_operations_.size() + issued_copy_operation_count_) >=
-           kMaxCopyOperations) {
-      // Ignore limit when shutdown is set.
-      if (shutdown_)
-        break;
-
-      ++failed_attempts;
-
-      // Schedule a check that will also wait for operations to complete
-      // after too many failed attempts.
-      bool wait_if_needed = failed_attempts > kFailedAttemptsBeforeWaitIfNeeded;
-
-      // Schedule a check for completed copy operations if too many operations
-      // are currently in-flight.
-      ScheduleCheckForCompletedCopyOperationsWithLockAcquired(wait_if_needed);
-
-      {
-        TRACE_EVENT0("cc", "WaitingForCopyOperationsToComplete");
-
-        // Wait for in-flight copy operations to drop below limit.
-        copy_operation_count_cv_.Wait();
-      }
-    }
-
-    // There may be more work available, so wake up another worker thread.
-    copy_operation_count_cv_.Signal();
-
-    // Copy at most |chunk_size_in_rows|.
-    int rows_to_copy = std::min(chunk_size_in_rows, height - y);
-    DCHECK_GT(rows_to_copy, 0);
-
-    // |raster_resource_write_lock| is passed to the first copy operation as it
-    // needs to be released before we can issue a copy.
-    pending_copy_operations_.push_back(make_scoped_ptr(new CopyOperation(
-        raster_resource_write_lock.Pass(), raster_resource, output_resource,
-        gfx::Rect(0, y, raster_resource->size().width(), rows_to_copy))));
-    y += rows_to_copy;
-
-    // Acquire a sequence number for this copy operation.
-    sequence = next_copy_operation_sequence_++;
-
-    // Increment |bytes_scheduled_since_last_flush_| by the amount of memory
-    // used for this copy operation.
-    bytes_scheduled_since_last_flush_ += rows_to_copy * bytes_per_row;
-
-    // Post task that will advance last flushed copy operation to |sequence|
-    // when |bytes_scheduled_since_last_flush_| has reached
-    // |max_bytes_per_copy_operation_|.
-    if (bytes_scheduled_since_last_flush_ >= max_bytes_per_copy_operation_) {
-      task_runner_->PostTask(
-          FROM_HERE,
-          base::Bind(&OneCopyTileTaskWorkerPool::AdvanceLastFlushedCopyTo,
-                     weak_ptr_factory_.GetWeakPtr(), sequence));
-      bytes_scheduled_since_last_flush_ = 0;
-    }
-  }
-
-  return sequence;
-}
-
-void OneCopyTileTaskWorkerPool::AdvanceLastIssuedCopyTo(
-    CopySequenceNumber sequence) {
-  if (last_issued_copy_operation_ >= sequence)
+  ResourceFormat format = resource_provider_->memory_efficient_texture_format();
+  std::for_each(buffers_.begin(), buffers_.end(),
+                [pmd, format](const StagingBuffer* buffer) {
+                  buffer->OnMemoryDump(pmd, format);
+                });
+
+  return true;
+}
+
+base::TimeTicks OneCopyTileTaskWorkerPool::GetUsageTimeForLRUBuffer() {
+  lock_.AssertAcquired();
+
+  if (!free_buffers_.empty())
+    return free_buffers_.front()->last_usage;
+
+  if (!busy_buffers_.empty())
+    return busy_buffers_.front()->last_usage;
+
+  return base::TimeTicks();
+}
+
+void OneCopyTileTaskWorkerPool::ScheduleReduceMemoryUsage() {
+  lock_.AssertAcquired();
+
+  if (reduce_memory_usage_pending_)
     return;
 
-  IssueCopyOperations(sequence - last_issued_copy_operation_);
-  last_issued_copy_operation_ = sequence;
-}
-
-void OneCopyTileTaskWorkerPool::AdvanceLastFlushedCopyTo(
-    CopySequenceNumber sequence) {
-  if (last_flushed_copy_operation_ >= sequence)
+  reduce_memory_usage_pending_ = true;
+
+  base::TimeTicks reduce_memory_usage_time =
+      GetUsageTimeForLRUBuffer() + staging_buffer_expiration_delay_;
+  task_runner_->PostDelayedTask(
+      FROM_HERE, reduce_memory_usage_callback_,
+      reduce_memory_usage_time - base::TimeTicks::Now());
+}
+
+void OneCopyTileTaskWorkerPool::ReduceMemoryUsage() {
+  base::AutoLock lock(lock_);
+
+  reduce_memory_usage_pending_ = false;
+
+  if (free_buffers_.empty() && busy_buffers_.empty())
     return;
 
-  AdvanceLastIssuedCopyTo(sequence);
-
-  // Flush all issued copy operations.
-  context_provider_->ContextGL()->ShallowFlushCHROMIUM();
-  last_flushed_copy_operation_ = last_issued_copy_operation_;
+  base::TimeTicks current_time = base::TimeTicks::Now();
+  ReleaseBuffersNotUsedSince(current_time - staging_buffer_expiration_delay_);
+
+  if (free_buffers_.empty() && busy_buffers_.empty())
+    return;
+
+  reduce_memory_usage_pending_ = true;
+
+  base::TimeTicks reduce_memory_usage_time =
+      GetUsageTimeForLRUBuffer() + staging_buffer_expiration_delay_;

[vmpstr, 2015/07/22 23:38:52]

Can you make a comment to what this time is...

UsageTime + staging_buffer_expiration - current_time... I guess that's when the
next buffer is going to expire (time ticks from now)?

[reveman, 2015/07/23 05:35:05]

Yes, lru buffer usage time + expiration delay is next time it makes sense to try
and reduce memory usage. We schedule a call to ReduceMemoryUsage at this time.
Comment added.

+  task_runner_->PostDelayedTask(FROM_HERE, reduce_memory_usage_callback_,
+                                reduce_memory_usage_time - current_time);
+}
+
+void OneCopyTileTaskWorkerPool::ReleaseBuffersNotUsedSince(
+    base::TimeTicks time) {
+  lock_.AssertAcquired();
+
+  ContextProvider* context_provider =
+      resource_provider_->output_surface()->worker_context_provider();
+  DCHECK(context_provider);
+
+  {
+    ContextProvider::ScopedContextGL scoped_context(context_provider);
+
+    gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
+    DCHECK(gl);
+
+    // Note: Front buffer is guaranteed to be LRU so we can stop releasing
+    // buffers as soon as we find a buffer that has been used since |time|.
+    while (!free_buffers_.empty()) {
+      if (free_buffers_.front()->last_usage > time)
+        return;
+
+      free_buffers_.front()->DestroyGLResources(gl);
+      buffers_.erase(free_buffers_.front());
+      free_buffers_.take_front();
+    }
+
+    while (!busy_buffers_.empty()) {
+      if (busy_buffers_.front()->last_usage > time)
+        return;
+
+      busy_buffers_.front()->DestroyGLResources(gl);
+      buffers_.erase(busy_buffers_.front());
+      busy_buffers_.take_front();
+    }
+  }
 }
 
 void OneCopyTileTaskWorkerPool::OnTaskSetFinished(TaskSet task_set) {
   TRACE_EVENT1("cc", "OneCopyTileTaskWorkerPool::OnTaskSetFinished", "task_set",
                task_set);
 
   DCHECK(tasks_pending_[task_set]);
   tasks_pending_[task_set] = false;
   if (tasks_pending_.any()) {
     TRACE_EVENT_ASYNC_STEP_INTO1("cc", "ScheduledTasks", this, "running",
                                  "state", StateAsValue());
   } else {
     TRACE_EVENT_ASYNC_END0("cc", "ScheduledTasks", this);
   }
   client_->DidFinishRunningTileTasks(task_set);
 }
 
-void OneCopyTileTaskWorkerPool::IssueCopyOperations(int64 count) {
-  TRACE_EVENT1("cc", "OneCopyTileTaskWorkerPool::IssueCopyOperations", "count",
-               count);
-
-  CopyOperation::Deque copy_operations;
-
-  {
-    base::AutoLock lock(lock_);
-
-    for (int64 i = 0; i < count; ++i) {
-      DCHECK(!pending_copy_operations_.empty());
-      copy_operations.push_back(pending_copy_operations_.take_front());
-    }
-
-    // Increment |issued_copy_operation_count_| to reflect the transition of
-    // copy operations from "pending" to "issued" state.
-    issued_copy_operation_count_ += copy_operations.size();
-  }
-
-  while (!copy_operations.empty()) {
-    scoped_ptr<CopyOperation> copy_operation = copy_operations.take_front();
-
-    // Remove the write lock.
-    copy_operation->src_write_lock.reset();
-
-    // Copy contents of source resource to destination resource.
-    resource_provider_->CopyResource(copy_operation->src->id(),
-                                     copy_operation->dst->id(),
-                                     copy_operation->rect);
-  }
-}
-
-void OneCopyTileTaskWorkerPool::
-    ScheduleCheckForCompletedCopyOperationsWithLockAcquired(
-        bool wait_if_needed) {
-  lock_.AssertAcquired();
-
-  if (check_for_completed_copy_operations_pending_)
-    return;
-
-  base::TimeTicks now = base::TimeTicks::Now();
-
-  // Schedule a check for completed copy operations as soon as possible but
-  // don't allow two consecutive checks to be scheduled to run less than the
-  // tick rate apart.
-  base::TimeTicks next_check_for_completed_copy_operations_time =
-      std::max(last_check_for_completed_copy_operations_time_ +
-                   base::TimeDelta::FromMilliseconds(
-                       kCheckForCompletedCopyOperationsTickRateMs),
-               now);
-
-  task_runner_->PostDelayedTask(
-      FROM_HERE,
-      base::Bind(&OneCopyTileTaskWorkerPool::CheckForCompletedCopyOperations,
-                 weak_ptr_factory_.GetWeakPtr(), wait_if_needed),
-      next_check_for_completed_copy_operations_time - now);
-
-  last_check_for_completed_copy_operations_time_ =
-      next_check_for_completed_copy_operations_time;
-  check_for_completed_copy_operations_pending_ = true;
-}
-
-void OneCopyTileTaskWorkerPool::CheckForCompletedCopyOperations(
-    bool wait_if_needed) {
-  TRACE_EVENT1("cc",
-               "OneCopyTileTaskWorkerPool::CheckForCompletedCopyOperations",
-               "wait_if_needed", wait_if_needed);
-
-  resource_pool_->CheckBusyResources(wait_if_needed);
-
-  {
-    base::AutoLock lock(lock_);
-
-    DCHECK(check_for_completed_copy_operations_pending_);
-    check_for_completed_copy_operations_pending_ = false;
-
-    // The number of busy resources in the pool reflects the number of issued
-    // copy operations that have not yet completed.
-    issued_copy_operation_count_ = resource_pool_->busy_resource_count();
-
-    // There may be work blocked on too many in-flight copy operations, so wake
-    // up a worker thread.
-    copy_operation_count_cv_.Signal();
-  }
-}
-
 scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 OneCopyTileTaskWorkerPool::StateAsValue() const {
   scoped_refptr<base::trace_event::TracedValue> state =
       new base::trace_event::TracedValue();
 
   state->BeginArray("tasks_pending");
   for (TaskSet task_set = 0; task_set < kNumberOfTaskSets; ++task_set)
     state->AppendBoolean(tasks_pending_[task_set]);
   state->EndArray();
   state->BeginDictionary("staging_state");
   StagingStateAsValueInto(state.get());
   state->EndDictionary();
 
   return state;
 }
 
 void OneCopyTileTaskWorkerPool::StagingStateAsValueInto(
     base::trace_event::TracedValue* staging_state) const {
-  staging_state->SetInteger(
-      "staging_resource_count",
-      static_cast<int>(resource_pool_->total_resource_count()));
-  staging_state->SetInteger(
-      "bytes_used_for_staging_resources",
-      static_cast<int>(resource_pool_->total_memory_usage_bytes()));
-  staging_state->SetInteger(
-      "pending_copy_count",
-      static_cast<int>(resource_pool_->total_resource_count() -
-                       resource_pool_->acquired_resource_count()));
-  staging_state->SetInteger(
-      "bytes_pending_copy",
-      static_cast<int>(resource_pool_->total_memory_usage_bytes() -
-                       resource_pool_->acquired_memory_usage_bytes()));
+  base::AutoLock lock(lock_);
+
+  staging_state->SetInteger("staging_buffer_count",
+                            static_cast<int>(buffers_.size()));
+  staging_state->SetInteger("busy_count",
+                            static_cast<int>(busy_buffers_.size()));
+  staging_state->SetInteger("free_count",
+                            static_cast<int>(free_buffers_.size()));
 }
 
 }  // namespace cc