Disable page navigation GC

third_party/WebKit/Source/platform/heap/ThreadState.cpp

 /*
  * Copyright (C) 2013 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 545 matching lines @@
     return judgeGCThreshold(1024 * 1024, 1.5);
 }
 
 bool ThreadState::shouldScheduleV8FollowupGC()
 {
     return judgeGCThreshold(32 * 1024 * 1024, 1.5);
 }
 
 bool ThreadState::shouldSchedulePageNavigationGC(float estimatedRemovalRatio)
 {
-    return judgeGCThreshold(1024 * 1024, 1.5 * (1 - estimatedRemovalRatio));
+    // If estimatedRemovalRatio is low we should let IdleGC handle this.
+    if (estimatedRemovalRatio == 0.01)

[haraken, 2016/02/14 23:23:04]

I'm confused with this branch.

- Are you intending 'estimatedRemovalRatio < 0.01'?

- I think estimatedRemovalRatio should be renamed to estimatedLiveNodesRatio. If
so, 'estimatedLiveNodesRatio < 0.01' means that "don't schedule a page
navigation GC if # of live nodes is small". This doesn't make sense.

- 'return false' won't schedule an idle GC.

[keishi, 2016/02/15 01:40:50]

Yes, sorry.
FrameLoader is calculating (# of nodes in detaching document) / (# of nodes) so
this isn't a live node ratio.

My thinking was that PageNavigationGC has penalties like impact on PLT and jank
so we should let normal IdleGC logic handle most of the time. If the
estimatedRemovalRatio is low this isn't really a PageNavigationGC, more like a
IdleGC with the extra penalties.

I'll fix the estimatedRemovalRatio and measure some more.

+        return false;
+    return judgeGCThreshold(32 * 1024 * 1024, 1.5 * (1 - estimatedRemovalRatio));
 }
 
 bool ThreadState::shouldForceConservativeGC()
 {
     // TODO(haraken): 400% is too large. Lower the heap growing factor.
     return judgeGCThreshold(32 * 1024 * 1024, 5.0);
 }
 
 // If we're consuming too much memory, trigger a conservative GC
 // aggressively. This is a safe guard to avoid OOM.
@@ skipping 76 matching lines @@
         dataLogF("Scheduled MemoryPressureGC\n");
 #endif
         Heap::collectGarbage(BlinkGC::HeapPointersOnStack, BlinkGC::GCWithoutSweep, BlinkGC::MemoryPressureGC);
         return;
     }
     if (shouldSchedulePageNavigationGC(estimatedRemovalRatio)) {
 #if PRINT_HEAP_STATS
         dataLogF("Scheduled PageNavigationGC\n");
 #endif
         schedulePageNavigationGC();
-        return;
     }
 }
 
 void ThreadState::schedulePageNavigationGC()
 {
     ASSERT(checkThread());
     ASSERT(!isSweepingInProgress());
     setGCState(PageNavigationGCScheduled);
 }
 
@@ skipping 824 matching lines @@
     threadDump->addScalar("dead_count", "objects", totalDeadCount);
     threadDump->addScalar("live_size", "bytes", totalLiveSize);
     threadDump->addScalar("dead_size", "bytes", totalDeadSize);
 
     WebMemoryAllocatorDump* heapsDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(heapsDumpName);
     WebMemoryAllocatorDump* classesDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(classesDumpName);
     BlinkGCMemoryDumpProvider::instance()->currentProcessMemoryDump()->addOwnershipEdge(classesDump->guid(), heapsDump->guid());
 }
 
 } // namespace blink