Oilpan: Schedule a conservative GC when page navigations are happening frequently

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 81 matching lines @@
     , m_startOfStack(reinterpret_cast<intptr_t*>(StackFrameDepth::getStackStart()))
     , m_endOfStack(reinterpret_cast<intptr_t*>(StackFrameDepth::getStackStart()))
     , m_safePointScopeMarker(nullptr)
     , m_atSafePoint(false)
     , m_interruptors()
     , m_sweepForbidden(false)
     , m_noAllocationCount(0)
     , m_gcForbiddenCount(0)
     , m_persistentAllocated(0)
     , m_persistentFreed(0)
+    , m_pageNavigationCount(0)
     , m_vectorBackingHeapIndex(Vector1HeapIndex)
     , m_currentHeapAges(0)
     , m_isTerminating(false)
     , m_gcMixinMarker(nullptr)
     , m_shouldFlushHeapDoesNotContainCache(false)
     , m_gcState(NoGCScheduled)
     , m_traceDOMWrappers(nullptr)
 #if defined(ADDRESS_SANITIZER)
     , m_asanFakeStack(__asan_get_current_fake_stack())
 #endif
@@ skipping 584 matching lines @@
     if (isGCForbidden())
         return;
 
     // Finish on-going lazy sweeping.
     // TODO(haraken): It might not make sense to force completeSweep() for all
     // page navigations.
     completeSweep();
     ASSERT(!isSweepingInProgress());
     ASSERT(!sweepForbidden());
 
+    ++m_pageNavigationCount;
+    if (m_pageNavigationCount >= 5) {
+        // A frame retains a lot of memory in the V8 side. V8's GC cannot
+        // collect the memory until Oilpan's GC collects the frame. So we
+        // force a conservative GC if no Oilpan's GC has been observed in
+        // the past 5 frame navigations.
+        Heap::collectGarbage(HeapPointersOnStack, GCWithoutSweep, Heap::ConservativeGC);
+        return;
+    }
+
     if (shouldSchedulePageNavigationGC(estimatedRemovalRatio))
         schedulePageNavigationGC();
 }
 
 void ThreadState::schedulePageNavigationGC()
 {
     ASSERT(checkThread());
     ASSERT(!isSweepingInProgress());
     setGCState(PageNavigationGCScheduled);
 }
@@ skipping 674 matching lines @@
 
     if (isMainThread())
         ScriptForbiddenScope::exit();
 }
 
 void ThreadState::clearHeapAges()
 {
     memset(m_heapAges, 0, sizeof(size_t) * NumberOfHeaps);
     memset(m_likelyToBePromptlyFreed.get(), 0, sizeof(int) * likelyToBePromptlyFreedArraySize);
     m_currentHeapAges = 0;
+    m_pageNavigationCount = 0;

[keishi, 2015/09/19 06:12:15]

nit: I'm not sure if this belongs here because it isn't related to heapAges.

[haraken, 2015/09/19 08:17:14]

Moved this to preGC.

 }
 
 int ThreadState::heapIndexOfVectorHeapLeastRecentlyExpanded(int beginHeapIndex, int endHeapIndex)
 {
     size_t minHeapAge = m_heapAges[beginHeapIndex];
     int heapIndexWithMinHeapAge = beginHeapIndex;
     for (int heapIndex = beginHeapIndex + 1; heapIndex <= endHeapIndex; heapIndex++) {
         if (m_heapAges[heapIndex] < minHeapAge) {
             minHeapAge = m_heapAges[heapIndex];
             heapIndexWithMinHeapAge = heapIndex;
@@ skipping 199 matching lines @@
         json->beginArray(it->key.ascii().data());
         for (size_t age = 0; age <= maxHeapObjectAge; ++age)
             json->pushInteger(it->value.ages[age]);
         json->endArray();
     }
     TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(TRACE_DISABLED_BY_DEFAULT("blink_gc"), statsName, this, json.release());
 }
 #endif
 
 } // namespace blink