[oilpan]: Don't sweep while in safepoint.

Source/platform/heap/ThreadState.cpp

Index: Source/platform/heap/ThreadState.cpp
diff --git a/Source/platform/heap/ThreadState.cpp b/Source/platform/heap/ThreadState.cpp
index af776ba616d92b59d2873b8aa605cf9062bb9aea..40de3661665d8ca1f1155228c56ea75b6adf3cfc 100644
--- a/Source/platform/heap/ThreadState.cpp
+++ b/Source/platform/heap/ThreadState.cpp
@@ -198,7 +198,7 @@ public:
             if (locker)
                 locker->reset();
             pushAllRegisters(this, state, parkAfterPushRegisters);
-            state->performPendingSweep();
+            state->setSweepRequested();

[haraken, 2014/06/26 13:52:11]

Do we need to call this?

I guess setSweepRequested is alerady called for all attached threads by the
GCing thread (see Heap::prepareForGC()).

[Mads Ager (chromium), 2014/06/26 13:52:40]

I don't think we need to actually set sweep requested here that should have been
already done otherwise the performPendingSweep call would do nothing here.

So it seem you can just remove performPendingSweep from here and call it after
checkAndPark.

[wibling-chromium, 2014/06/27 10:07:48]

No, that is actually wrong. We risk sweeping when no marking has been done. Will
remove.

[wibling-chromium, 2014/06/27 10:07:48]

Done.

         }
     }
 
@@ -758,6 +758,7 @@ void ThreadState::safePoint(StackState stackState)
     s_safePointBarrier->checkAndPark(this);
     m_atSafePoint = false;
     m_stackState = HeapPointersOnStack;
+    performPendingSweep();
 }
 
 #ifdef ADDRESS_SANITIZER