Experiment with more aggressive MSE GC on memory pressure

media/blink/webmediaplayer_impl.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 "media/blink/webmediaplayer_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
 #include "base/debug/crash_logging.h"
 #include "base/location.h"
+#include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/task_runner_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "cc/blink/web_layer_impl.h"
 #include "cc/layers/video_layer.h"
 #include "media/audio/null_audio_sink.h"
@@ skipping 207 matching lines @@
       surface_manager_(params.surface_manager()),
       overlay_surface_id_(SurfaceManager::kNoSurfaceID),
       suppress_destruction_errors_(false),
       can_suspend_state_(CanSuspendState::UNKNOWN),
       use_fallback_path_(false),
       is_encrypted_(false),
       underflow_count_(0),
       preroll_attempt_pending_(false),
       observer_(params.media_observer()),
       max_keyframe_distance_to_disable_background_video_(
-          params.max_keyframe_distance_to_disable_background_video()) {
+          params.max_keyframe_distance_to_disable_background_video()),
+      enable_instant_source_buffer_gc_(
+          params.enable_instant_source_buffer_gc()) {
   DCHECK(!adjust_allocated_memory_cb_.is_null());
   DCHECK(renderer_factory_);
   DCHECK(client_);
   DCHECK(delegate_);
 
   tick_clock_.reset(new base::DefaultTickClock());
 
   force_video_overlays_ = base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kForceVideoOverlays);
 
@@ skipping 902 matching lines @@
 
   UpdateBackgroundVideoOptimizationState();
 }
 
 void WebMediaPlayerImpl::OnDemuxerOpened() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   client_->mediaSourceOpened(
       new WebMediaSourceImpl(chunk_demuxer_, media_log_));
 }
 
+void WebMediaPlayerImpl::OnMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  DVLOG(2) << __func__ << " memory_pressure_level=" << memory_pressure_level;
+  DCHECK(main_task_runner_->BelongsToCurrentThread());
+  DCHECK(base::FeatureList::IsEnabled(kMemoryPressureBasedSourceBufferGC));
+  DCHECK(chunk_demuxer_);
+
+  // The new value of |memory_pressure_level| will take effect on the next
+  // garbage collection. Typically this means the next SourceBuffer append()
+  // operation, since per MSE spec, the garbage collection must only occur
+  // during SourceBuffer append(). But if memory pressure is critical it might
+  // be better to perform GC immediately rather than wait for the next append
+  // and potentially get killed due to out-of-memory.
+  // So if this experiment is enabled and pressure level is critical, we'll pass
+  // down force_gc==true, which will force immediate GC on SourceBufferStreams.
+  bool force_gc =
+      (enable_instant_source_buffer_gc_ &&
+       memory_pressure_level ==
+           base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL);
+
+  // base::Unretained is safe, since chunk_demuxer_ is actually owned by
+  // |this| via this->demuxer_.
+  media_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&ChunkDemuxer::OnMemoryPressure,
+                            base::Unretained(chunk_demuxer_),
+                            base::TimeDelta::FromSecondsD(currentTime()),
+                            memory_pressure_level, force_gc));
+}
+
 void WebMediaPlayerImpl::OnError(PipelineStatus status) {
   DVLOG(1) << __func__;
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   DCHECK_NE(status, PIPELINE_OK);
 
   if (suppress_destruction_errors_)
     return;
 
   ReportPipelineError(load_type_, frame_->getSecurityOrigin(), status);
   media_log_->AddEvent(media_log_->CreatePipelineErrorEvent(status));
@@ skipping 529 matching lines @@
     return;
 #endif
   } else {
     DCHECK(!chunk_demuxer_);
     DCHECK(!data_source_);
 
     chunk_demuxer_ = new ChunkDemuxer(
         BIND_TO_RENDER_LOOP(&WebMediaPlayerImpl::OnDemuxerOpened),
         encrypted_media_init_data_cb, media_log_);
     demuxer_.reset(chunk_demuxer_);
+
+    if (base::FeatureList::IsEnabled(kMemoryPressureBasedSourceBufferGC)) {
+      // base::Unretained is safe because |this| owns memory_pressure_listener_.
+      memory_pressure_listener_ =
+          base::MakeUnique<base::MemoryPressureListener>(base::Bind(
+              &WebMediaPlayerImpl::OnMemoryPressure, base::Unretained(this)));
+    }
   }
 
   // TODO(sandersd): FileSystem objects may also be non-static, but due to our
   // caching layer such situations are broken already. http://crbug.com/593159
   bool is_static = !chunk_demuxer_;
   bool is_streaming = IsStreaming();
   UMA_HISTOGRAM_BOOLEAN("Media.IsStreaming", is_streaming);
 
   // ... and we're ready to go!
   // TODO(sandersd): On Android, defer Start() if the tab is not visible.
@@ skipping 527 matching lines @@
     UMA_HISTOGRAM_TIMES(
         "Media.Video.TimeFromForegroundToFirstFrame.DisableTrack",
         time_to_first_frame);
   } else {
     UMA_HISTOGRAM_TIMES("Media.Video.TimeFromForegroundToFirstFrame.Paused",
                         time_to_first_frame);
   }
 }
 
 }  // namespace media