Parallel and concurrent sweeping.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 401f4f7948adc09cb845390ef7f37036fa179aee..45db7dd065b5231df81003bff572a4530366340a 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -1273,7 +1273,14 @@ void Heap::Scavenge() {
 
   incremental_marking()->PrepareForScavenge();
 
-  AdvanceSweepers(static_cast<int>(new_space_.Size()));
+  MarkCompactCollector* mark_compact = mark_compact_collector();
+
+  if (!mark_compact->AreSweeperThreadsActivated()) {
+     AdvanceSweepers(static_cast<int>(new_space_.Size()));
+  } else if (FLAG_concurrent_sweeping) {
+    mark_compact->StealMemoryFromSweeperThreads(paged_space(OLD_DATA_SPACE));
+    mark_compact->StealMemoryFromSweeperThreads(paged_space(OLD_POINTER_SPACE));
+  }

[Michael Starzinger, 2013/01/28 16:30:18]

What we actually wanna ensure here is that we made enough progress in sweeping
so that the Scavanger can in the worst case promote all objects from new-space.
So I think the right thing here is to call PagedSpace::EnsureSweeperProgress on
the old-data-space and old-pointer-space, no matter which mode we are in.

[Hannes Payer (out of office), 2013/01/30 10:11:27]

Right, but this changes the current non-parallel non-concurrent behavior.

On 2013/01/28 16:30:18, Michael Starzinger wrote:

 
   // Flip the semispaces.  After flipping, to space is empty, from space has
   // live objects.
@@ -5374,7 +5381,8 @@ bool Heap::IdleNotification(int hint) {
 
 

[Michael Starzinger, 2013/01/28 16:30:18]

I know it's not your change, but drop one of the two empty newlines.

[Hannes Payer (out of office), 2013/01/30 10:11:27]

Done.

   if (incremental_marking()->IsStopped()) {
-    if (!IsSweepingComplete() &&
+    if (!mark_compact_collector()->AreSweeperThreadsActivated() &&
+        !IsSweepingComplete() &&
         !AdvanceSweepers(static_cast<int>(step_size))) {
       return false;
     }