- Add and enable concurrent sweeper.

runtime/vm/gc_sweeper.h

Index: runtime/vm/gc_sweeper.h
===================================================================
--- runtime/vm/gc_sweeper.h	(revision 39568)
+++ runtime/vm/gc_sweeper.h	(working copy)
@@ -13,6 +13,8 @@
 class FreeList;
 class Heap;
 class HeapPage;
+class Isolate;
+class PageSpace;
 
 // The class GCSweeper is used to visit the heap after marking to reclaim unused
 // memory.
@@ -30,6 +32,12 @@
   // last marked object.
   intptr_t SweepLargePage(HeapPage* page);
 
+  static void SweepConcurrent(Isolate* isolate,

[koda, 2014/08/26 23:34:48]

Comment on:
* whether 'last' is exclusive
* locking state of 'freelist'
* can 'isolate' be anything else than the owner of 'old_space'?

[Ivan Posva, 2014/08/27 01:00:21]

Done.

+                              PageSpace* old_space,
+                              HeapPage* first,
+                              HeapPage* last,
+                              FreeList* freelist);
+
  private:
   Heap* heap_;