[v8-dev] When scanning for grey objects, fill the deque until it flows over (issue 997093002 by [email protected])

Wed, 11 Mar 2015 03:49:31 -0700 

Reviewers: Hannes Payer,

Description:
When scanning for grey objects, fill the deque until it flows over

If we just fill it until it is full, and EmptyMarkingDeque() manages it
to process without overflowing it, then ProcessMarkingDeque() will not
scan for additional grey objects.

BUG=none
[email protected]
LOG=n

Please review this at https://codereview.chromium.org/997093002/

Base URL: https://chromium.googlesource.com/v8/v8.git@master

Affected files (+14, -14 lines):
  M 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 44262e42b162b58974cf7b2092ea141047856d2a..83c2cd28714e59852f0dd70ae13f07d464fd36c5 100644 
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -1764,7 +1764,7 @@ static void DiscoverGreyObjectsWithIterator(Heap* heap, 
                                             T* it) {
   // The caller should ensure that the marking stack is initially not full,
   // so that we don't waste effort pointlessly scanning for objects.
-  DCHECK(!marking_deque->IsFull());
+  DCHECK(!marking_deque->overflowed());

   Map* filler_map = heap->one_pointer_filler_map();
for (HeapObject* object = it->Next(); object != NULL; object = it->Next()) { @@ -1773,7 +1773,7 @@ static void DiscoverGreyObjectsWithIterator(Heap* heap, 
       Marking::GreyToBlack(markbit);
MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size()); 
       marking_deque->PushBlack(object);
-      if (marking_deque->IsFull()) return;
+      if (marking_deque->overflowed()) return;
     }
   }
 }
@@ -1784,7 +1784,7 @@ static inline int MarkWordToObjectStarts(uint32_t mark_bits, int* starts); 

 static void DiscoverGreyObjectsOnPage(MarkingDeque* marking_deque,
                                       MemoryChunk* p) {
-  DCHECK(!marking_deque->IsFull());
+  DCHECK(!marking_deque->overflowed());
   DCHECK(strcmp(Marking::kWhiteBitPattern, "00") == 0);
   DCHECK(strcmp(Marking::kBlackBitPattern, "10") == 0);
   DCHECK(strcmp(Marking::kGreyBitPattern, "11") == 0);
@@ -1818,7 +1818,7 @@ static void DiscoverGreyObjectsOnPage(MarkingDeque* marking_deque, 
       HeapObject* object = HeapObject::FromAddress(addr);
MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size()); 
       marking_deque->PushBlack(object);
-      if (marking_deque->IsFull()) return;
+      if (marking_deque->overflowed()) return;
       offset += 2;
       grey_objects >>= 2;
     }
@@ -1896,7 +1896,7 @@ static void DiscoverGreyObjectsInSpace(Heap* heap, MarkingDeque* marking_deque, 
   while (it.has_next()) {
     Page* p = it.next();
     DiscoverGreyObjectsOnPage(marking_deque, p);
-    if (marking_deque->IsFull()) return;
+    if (marking_deque->overflowed()) return;
   }
 }

@@ -1908,7 +1908,7 @@ static void DiscoverGreyObjectsInNewSpace(Heap* heap,
   while (it.has_next()) {
     NewSpacePage* page = it.next();
     DiscoverGreyObjectsOnPage(marking_deque, page);
-    if (marking_deque->IsFull()) return;
+    if (marking_deque->overflowed()) return;
   }
 }

@@ -2034,31 +2034,31 @@ void MarkCompactCollector::RefillMarkingDeque() {
   DCHECK(marking_deque_.overflowed());

   DiscoverGreyObjectsInNewSpace(heap(), &marking_deque_);
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;

   DiscoverGreyObjectsInSpace(heap(), &marking_deque_,
                              heap()->old_pointer_space());
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;
DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->old_data_space()); 
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;
DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->code_space()); 
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;

   DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->map_space());
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;
DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->cell_space()); 
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;

   DiscoverGreyObjectsInSpace(heap(), &marking_deque_,
                              heap()->property_cell_space());
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;

   LargeObjectIterator lo_it(heap()->lo_space());
   DiscoverGreyObjectsWithIterator(heap(), &marking_deque_, &lo_it);
-  if (marking_deque_.IsFull()) return;
+  if (marking_deque_.overflowed()) return;

   marking_deque_.ClearOverflowed();
 }


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