Use the card table to speed up the GSS collector.

Scan only dirty cards, as opposed to the whole space, to find
references from the non-moving spaces to the bump pointer spaces at
bump pointer space only collections.

With this change, the Ritz MemAllocTest speeds up by 8-10% on host and
2-3% on N4. The Ritz EvaluateFibonacci speeds up by 8% and its average
pause time is reduced by 43% on N4.

Bug: 11650816
Change-Id: I1eefe75776bc37e24673b301ffa65a25f9bd4cde

1 files changed, 9 insertions, 1 deletions

diff --git a/runtime/gc/heap.h b/runtime/gc/heap.h
index 1e0a596..de20a4e 100644
--- a/runtime/gc/heap.h
+++ b/runtime/gc/heap.h
@@ -56,6 +56,7 @@ namespace accounting {
   class HeapBitmap;
   class ModUnionTable;
   class ObjectSet;
+  class RememberedSet;
 }  // namespace accounting
 
 namespace collector {
@@ -541,6 +542,10 @@ class Heap {
   accounting::ModUnionTable* FindModUnionTableFromSpace(space::Space* space);
   void AddModUnionTable(accounting::ModUnionTable* mod_union_table);
 
+  accounting::RememberedSet* FindRememberedSetFromSpace(space::Space* space);
+  void AddRememberedSet(accounting::RememberedSet* remembered_set);
+  void RemoveRememberedSet(space::Space* space);
+
   bool IsCompilingBoot() const;
   bool HasImageSpace() const;
 
@@ -660,7 +665,7 @@ class Heap {
   void SwapStacks(Thread* self);
 
   // Clear cards and update the mod union table.
-  void ProcessCards(TimingLogger& timings);
+  void ProcessCards(TimingLogger& timings, bool use_rem_sets);
 
   // Signal the heap trim daemon that there is something to do, either a heap transition or heap
   // trim.
@@ -701,6 +706,9 @@ class Heap {
   // A mod-union table remembers all of the references from the it's space to other spaces.
   SafeMap<space::Space*, accounting::ModUnionTable*> mod_union_tables_;
 
+  // A remembered set remembers all of the references from the it's space to the target space.
+  SafeMap<space::Space*, accounting::RememberedSet*> remembered_sets_;
+
   // Keep the free list allocator mem map lying around when we transition to background so that we
   // don't have to worry about virtual address space fragmentation.
   UniquePtr<MemMap> allocator_mem_map_;