Do V8 GC ASAP if system memory is pressured

content/renderer/render_thread_impl.cc

 // 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.
 
 #include "content/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
@@ skipping 142 matching lines @@
 #include "third_party/WebKit/public/web/WebMemoryPressureListener.h"
 #include "third_party/WebKit/public/web/WebNetworkStateNotifier.h"
 #include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "third_party/WebKit/public/web/WebScriptController.h"
 #include "third_party/WebKit/public/web/WebSecurityPolicy.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "third_party/icu/source/i18n/unicode/timezone.h"
 #include "third_party/skia/include/core/SkGraphics.h"
 #include "ui/base/layout.h"
 #include "ui/base/ui_base_switches.h"
-#include "v8/include/v8.h"
 
 #if defined(OS_ANDROID)
 #include <cpu-features.h>
 #include "content/renderer/android/synchronous_compositor_external_begin_frame_source.h"
 #include "content/renderer/android/synchronous_compositor_factory.h"
 #include "content/renderer/android/synchronous_compositor_filter.h"
 #include "content/renderer/media/android/renderer_demuxer_android.h"
 #include "content/renderer/media/android/stream_texture_factory_impl.h"
 #include "media/base/android/media_codec_util.h"
 #endif
@@ skipping 167 matching lines @@
     blink::enableLogChannel(t.token().c_str());
 }
 
 void NotifyTimezoneChangeOnThisThread() {
   v8::Isolate* isolate = v8::Isolate::GetCurrent();
   if (!isolate)
     return;
   v8::Date::DateTimeConfigurationChangeNotification(isolate);
 }
 
-void LowMemoryNotificationOnThisThread() {
-  v8::Isolate* isolate = v8::Isolate::GetCurrent();
-  if (!isolate)
-    return;
-  isolate->LowMemoryNotification();
-}
-
 class RenderFrameSetupImpl : public mojom::RenderFrameSetup {
  public:
   explicit RenderFrameSetupImpl(
       mojo::InterfaceRequest<mojom::RenderFrameSetup> request)
       : routing_id_highmark_(-1), binding_(this, std::move(request)) {}
 
   void ExchangeInterfaceProviders(
       int32_t frame_routing_id,
       shell::mojom::InterfaceProviderRequest services,
       shell::mojom::InterfaceProviderPtr exposed_services) override {
@@ skipping 427 matching lines @@
   media::InitializeMediaLibrary();
 
 #if defined(OS_ANDROID)
   if (!command_line.HasSwitch(switches::kDisableAcceleratedVideoDecode) &&
       media::MediaCodecUtil::IsMediaCodecAvailable()) {
     media::EnablePlatformDecoderSupport();
   }
 #endif
 
   memory_pressure_listener_.reset(new base::MemoryPressureListener(
-      base::Bind(&RenderThreadImpl::OnMemoryPressure, base::Unretained(this))));
+      base::Bind(&RenderThreadImpl::OnMemoryPressure, base::Unretained(this)),
+      base::Bind(&RenderThreadImpl::OnSyncMemoryPressure,
+                 base::Unretained(this))));
 
   int num_raster_threads = 0;
   std::string string_value =
       command_line.GetSwitchValueASCII(switches::kNumRasterThreads);
   bool parsed_num_raster_threads =
       base::StringToInt(string_value, &num_raster_threads);
   DCHECK(parsed_num_raster_threads) << string_value;
   DCHECK_GT(num_raster_threads, 0);
 
 #if defined(OS_ANDROID)
@@ skipping 1155 matching lines @@
     const WorkerProcessMsg_CreateWorker_Params& params) {
   // EmbeddedSharedWorkerStub will self-destruct.
   new EmbeddedSharedWorkerStub(
       params.url, params.name, params.content_security_policy,
       params.security_policy_type, params.creation_address_space,
       params.pause_on_start, params.route_id);
 }
 
 void RenderThreadImpl::OnMemoryPressure(
     base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  TRACE_EVENT0("memory","RenderThreadImpl::OnMemoryPressure");
   ReleaseFreeMemory();
 
   // Do not call into blink if it is not initialized.
   if (blink_platform_impl_) {
     blink::WebMemoryPressureListener::onMemoryPressure(
         static_cast<blink::WebMemoryPressureLevel>(memory_pressure_level));
 
-    if (blink::mainThreadIsolate()) {
-      // Trigger full v8 garbage collection on memory pressure notifications.
-      // This will potentially hang the renderer for a long time, however, when
-      // we receive a memory pressure notification, we might be about to be
-      // killed. Because of the janky hang don't do this to foreground
-      // renderers.
-      if (RendererIsHidden()) {
-        blink::mainThreadIsolate()->LowMemoryNotification();
-        RenderThread::Get()->PostTaskToAllWebWorkers(
-            base::Bind(&LowMemoryNotificationOnThisThread));
-      }
-    }
-
     if (memory_pressure_level ==
         base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) {
       // Purge Skia font cache, by setting it to 0 and then again to the
       // previous limit.
       size_t font_cache_limit = SkGraphics::SetFontCacheLimit(0);
       SkGraphics::SetFontCacheLimit(font_cache_limit);
     }
   }
 }
 
@@ skipping 134 matching lines @@
 RenderThreadImpl::PendingRenderFrameConnect::~PendingRenderFrameConnect() {
 }
 
 void RenderThreadImpl::PendingRenderFrameConnect::OnConnectionError() {
   size_t erased =
       RenderThreadImpl::current()->pending_render_frame_connects_.erase(
           routing_id_);
   DCHECK_EQ(1u, erased);
 }
 
+void RenderThreadImpl::OnSyncMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  if (blink::mainThreadIsolate()) {

[esprehn, 2016/04/18 21:57:59]

early return instead of indenting the entire function

[hong.zheng, 2016/04/19 06:27:43]

Done.

+    static_assert(
+        static_cast<v8::MemoryPressureLevel>(
+            base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE) ==

[esprehn, 2016/04/18 21:57:59]

these static_asserts should just be in a block at the top of the file, they
don't need to be inside the function

[hong.zheng, 2016/04/19 06:27:43]

Done.

+                v8::MemoryPressureLevel::kNone, "none level not align");
+    static_assert(
+        static_cast<v8::MemoryPressureLevel>(
+            base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE) ==
+                v8::MemoryPressureLevel::kModerate, "moderate level not align");
+    static_assert(
+        static_cast<v8::MemoryPressureLevel>(
+            base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) ==
+                v8::MemoryPressureLevel::kCritical, "critical level not align");
+
+    v8::MemoryPressureLevel v8_memory_pressure_level =
+        static_cast<v8::MemoryPressureLevel>(memory_pressure_level);
+
+    if (!RendererIsHidden()) {
+      if (v8_memory_pressure_level == v8::MemoryPressureLevel::kCritical)

[esprehn, 2016/04/18 21:57:58]

combine the if statements, doing:

if (x) {
  if (y)
    // comment
    thing();
}

is very hard to read.

// comment
if (x && y)
  thing();

[hong.zheng, 2016/04/19 06:27:43]

Done.

+        // In order to reduce performance impact, translate critical level to
+        // moderate level for foregroud renderer.
+        v8_memory_pressure_level = v8::MemoryPressureLevel::kModerate;
+    }
+
+    blink::mainThreadIsolate()->MemoryPressureNotification(
+        v8_memory_pressure_level);
+    blink::MemoryPressureNotificationToWorkerThreadIsolates(
+        v8_memory_pressure_level);
+  }
+}
+
 }  // namespace content