Oilpan: Reduce the reserved size of CallbackStacks

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

Index: third_party/WebKit/Source/platform/heap/Heap.cpp
diff --git a/third_party/WebKit/Source/platform/heap/Heap.cpp b/third_party/WebKit/Source/platform/heap/Heap.cpp
index 8a414e3ec0378d68a144275f1cf59b6561e47c60..9296517eb4a1431929802989b4ce27d19d487a20 100644
--- a/third_party/WebKit/Source/platform/heap/Heap.cpp
+++ b/third_party/WebKit/Source/platform/heap/Heap.cpp
@@ -158,10 +158,10 @@ void Heap::flushHeapDoesNotContainCache()
 void Heap::init()
 {
     ThreadState::init();
-    s_markingStack = new CallbackStack();
-    s_postMarkingCallbackStack = new CallbackStack();
-    s_globalWeakCallbackStack = new CallbackStack();
-    s_ephemeronStack = new CallbackStack();
+    s_markingStack = new CallbackStack(4096);

[sof, 2016/02/14 21:47:03]

These are fairly arbitrary numbers, are they based on experiments showing that
these are reasonable averages / N-percentile of what's commonly seen?

+    s_postMarkingCallbackStack = new CallbackStack(128);
+    s_globalWeakCallbackStack = new CallbackStack(2048);
+    s_ephemeronStack = new CallbackStack(128);
     s_heapDoesNotContainCache = new HeapDoesNotContainCache();
     s_freePagePool = new FreePagePool();
     s_orphanedPagePool = new OrphanedPagePool();
@@ -367,6 +367,11 @@ void Heap::postGC(BlinkGC::GCType gcType)
     ASSERT(ThreadState::current()->isInGC());
     for (ThreadState* state : ThreadState::attachedThreads())
         state->postGC(gcType);
+
+    ASSERT(s_markingStack->isEmpty());
+    ASSERT(s_postMarkingCallbackStack->isEmpty());
+    ASSERT(s_globalWeakCallbackStack->isEmpty());
+    ASSERT(s_ephemeronStack->isEmpty());
 }
 
 const char* Heap::gcReasonString(BlinkGC::GCReason reason)