Trigger Blink GC on v8::kGCCallbackFlagCollectAllExternalMemory

third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 369 matching lines @@
         // low memory notifications.
         if (flags & v8::kGCCallbackFlagCollectAllAvailableGarbage) {
             // This single GC is not enough. See the above comment.
             ThreadHeap::collectGarbage(BlinkGC::HeapPointersOnStack, BlinkGC::GCWithSweep, BlinkGC::ForcedGC);
 
             // The conservative GC might have left floating garbage. Schedule
             // precise GC to ensure that we collect all available garbage.
             if (ThreadState::current())
                 ThreadState::current()->schedulePreciseGC();
         }
+
+        if (flags & v8::kGCCallbackFlagCollectAllExternalMemory)

[haraken, 2016/08/12 07:08:48]

Do you think it's worth distinguishing kGCCallbackFlagCollectAllExternalMemory
from kGCCallbackFlagCollectAllAvailableGarbage?

[keishi, 2016/08/15 10:30:44]

I'm not sure. I was thinking of maybe calling MemoryCache::purgeAll
kGCCallbackFlagCollectAllExternalMemory in the future and
v8::Heap::CollectAllAvailableGarbage seems to be called from many places.

+            ThreadHeap::collectGarbage(BlinkGC::HeapPointersOnStack, BlinkGC::GCWithSweep, BlinkGC::ForcedGC);
     }
 
     TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "UpdateCounters", TRACE_EVENT_SCOPE_THREAD, "data", InspectorUpdateCountersEvent::data());
 }
 
 void V8GCController::collectGarbage(v8::Isolate* isolate)
 {
     v8::HandleScope handleScope(isolate);
     RefPtr<ScriptState> scriptState = ScriptState::create(v8::Context::New(isolate), DOMWrapperWorld::create(isolate));
     ScriptState::Scope scope(scriptState.get());
@@ skipping 91 matching lines @@
     DEFINE_THREAD_SAFE_STATIC_LOCAL(CustomCountHistogram, scanPendingActivityHistogram, new CustomCountHistogram("Blink.ScanPendingActivityDuration", 1, 1000, 50));
     double startTime = WTF::currentTimeMS();
     v8::HandleScope scope(isolate);
     PendingActivityVisitor visitor(isolate, executionContext);
     toIsolate(executionContext)->VisitHandlesWithClassIds(&visitor);
     scanPendingActivityHistogram.count(static_cast<int>(WTF::currentTimeMS() - startTime));
     return visitor.pendingActivityFound();
 }
 
 } // namespace blink