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 358 matching lines @@
             // GCController.collectAll() forces multiple V8's GC.
             ThreadHeap::collectGarbage(BlinkGC::HeapPointersOnStack, BlinkGC::GCWithSweep, BlinkGC::ForcedGC);
 
             // Forces a precise GC at the end of the current event loop.
             RELEASE_ASSERT(!ThreadState::current()->isInGC());
             ThreadState::current()->setGCState(ThreadState::FullGCScheduled);
         }
 
         // v8::kGCCallbackFlagCollectAllAvailableGarbage is used when V8 handles
         // low memory notifications.
-        if (flags & v8::kGCCallbackFlagCollectAllAvailableGarbage) {
+        if (flags & v8::kGCCallbackFlagCollectAllAvailableGarbage
+            && flags & v8::kGCCallbackFlagCollectAllExternalMemory) {

[haraken, 2016/08/25 05:22:29]

Add () to make the condition clearer.

Shouldn't it be ||, not &&?

[keishi, 2016/08/25 05:25:05]

oops. Done

             // 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();
         }
     }
 
@@ skipping 100 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