On store buffer overflow we mark individidual pages for...

src/mark-compact.cc

Index: src/mark-compact.cc
===================================================================
--- src/mark-compact.cc	(revision 7374)
+++ src/mark-compact.cc	(working copy)
@@ -1726,6 +1726,7 @@
     if (Heap::new_space()->Contains(obj)) {
       ASSERT(Heap::InFromSpace(*p));
       *p = HeapObject::FromAddress(Memory::Address_at(old_addr));
+      StoreBuffer::EnterDirectlyIntoStoreBuffer(reinterpret_cast<Address>(p));

[Vyacheslav Egorov (Chromium), 2011/03/28 15:13:19]

This visitor is used to visit new space objects.

Their slots should not be entered into store-buffer.

[Erik Corry, 2011/03/28 15:56:07]

Good catch!

     }
   }
 };
@@ -1846,7 +1847,9 @@
   int survivors_size = 0;
 
   // First pass: traverse all objects in inactive semispace, remove marks,
-  // migrate live objects and write forwarding addresses.
+  // migrate live objects and write forwarding addresses.  This stage puts
+  // new entries in the store buffer and may cause some pages to be marked
+  // scan-on-scavenge.
   for (Address current = from_bottom; current < from_top; current += size) {
     HeapObject* object = HeapObject::FromAddress(current);
 
@@ -1899,7 +1902,7 @@
   LiveObjectList::IterateElements(&updating_visitor);
 
   {
-    StoreBufferRebuildScope scope;
+    StoreBufferRebuildScope scope(&Heap::ScavengeStoreBufferCallback);
     StoreBuffer::IteratePointersToNewSpace(&UpdatePointerToNewGen);
   }
 
@@ -2403,10 +2406,6 @@
                                       SweeperType sweeper) {
   space->set_was_swept_conservatively(sweeper == CONSERVATIVE);
 
-  // We don't have a linear allocation area while sweeping.  It will be restored
-  // on the first allocation after the sweep.
-  space->SetTop(NULL, NULL);
-
   space->ClearStats();
 
   PageIterator it(space);