[heap] Concurrent slot filtering in sweeper threads.

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index 7e5ef96fc9889cbcf3d7ea9dbfb3a7202383373b..7c12f04b6bd24b1d8ecbfb49eeb802cfc96c498c 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -302,24 +302,6 @@ bool MarkCompactCollector::StartCompaction(CompactionMode mode) {
   return compacting_;
 }
 
-void MarkCompactCollector::ClearInvalidRememberedSetSlots() {
-  {
-    TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_CLEAR_STORE_BUFFER);
-    RememberedSet<OLD_TO_NEW>::ClearInvalidSlots(heap());
-  }
-// There is not need to filter the old to old set because
-// it is completely cleared after the mark-compact GC.
-// The slots that become invalid due to runtime transitions are
-// cleared eagerly immediately after the transition.
-
-#ifdef VERIFY_HEAP
-  if (FLAG_verify_heap) {
-    RememberedSet<OLD_TO_NEW>::VerifyValidSlots(heap());
-    RememberedSet<OLD_TO_OLD>::VerifyValidSlots(heap());
-  }
-#endif
-}
-
 void MarkCompactCollector::CollectGarbage() {
   // Make sure that Prepare() has been called. The individual steps below will
   // update the state as they proceed.
@@ -2410,8 +2392,6 @@ void MarkCompactCollector::ClearNonLiveReferences() {
   MarkDependentCodeForDeoptimization(dependent_code_list);
 
   ClearWeakCollections();
-
-  ClearInvalidRememberedSetSlots();
 }
 
 
@@ -3825,10 +3805,13 @@ int MarkCompactCollector::Sweeper::ParallelSweepPage(Page* page,
     if (identity == NEW_SPACE) {
       RawSweep(page, IGNORE_FREE_LIST, free_space_mode);
     } else if (identity == OLD_SPACE) {
+      RememberedSet<OLD_TO_NEW>::ClearInvalidSlots(heap_, page);

[Michael Lippautz, 2016/10/06 13:02:19]

Not change in this CL, but you could simplify the branching here :)

[Hannes Payer (out of office), 2016/10/06 13:22:40]

Done.

       max_freed = RawSweep(page, REBUILD_FREE_LIST, free_space_mode);
     } else if (identity == CODE_SPACE) {
+      RememberedSet<OLD_TO_NEW>::ClearInvalidTypedSlots(heap_, page);
       max_freed = RawSweep(page, REBUILD_FREE_LIST, free_space_mode);
     } else {
+      RememberedSet<OLD_TO_NEW>::ClearInvalidSlots(heap_, page);
       max_freed = RawSweep(page, REBUILD_FREE_LIST, free_space_mode);
     }