commit 858f1c5fd5e528d0b16040ced74d4636046a42d8
author Mathieu Chartier <mathieuc@google.com> Wed Oct 17 17:45:55 2012 -0700
committer Android (Google) Code Review <android-gerrit@google.com> Tue Oct 23 10:38:45 2012 -0700
tree 3cfe50b75962353cdd62ec68112f3f148f026506
parent ef851d3058abfc56ed544f25d387dc7ff9c32e0b

Check point root marking.

Added thread list checkpoint function, this goes through every thread and runs
the checkpoint on each thread. Threads that are runnable run the checkpoint
callback themselves in the next suspend check, while suspended threads are
left suspended but have the callback called on them.

Added a checkpoint visitor member to each thread, this visitor called when the
checkpoint request flag is set during transitions to suspended from runnable.

Using the checkpoint to mark the roots reduces the first pause of partial /
full gc to around 1 ms.

Change-Id: I97239cc72ee0e4a3397e9138a62ee559268dce0a

src/gc/mark_sweep.h

diff --git a/src/gc/mark_sweep.h b/src/gc/mark_sweep.h
index ed74f99..d64439f 100644
--- a/src/gc/mark_sweep.h
+++ b/src/gc/mark_sweep.h
@@ -25,6 +25,7 @@
 
 namespace art {
 
+class Barrier;
 class CheckObjectVisitor;
 class Class;
 class Heap;
@@ -52,9 +53,15 @@
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
+  void MarkNonThreadRoots()
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
+
   void MarkConcurrentRoots();
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
 
+  void MarkRootsCheckpoint();
+       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
+
   // Verify that image roots point to only marked objects within the alloc space.
   void VerifyImageRoots() EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
 
@@ -183,6 +190,11 @@
     }
   }
 
+  static void MarkObjectVisitor(const Object* root, void* arg)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
+
+  Barrier& GetBarrier();
+
  private:
   // Returns true if the object has its bit set in the mark bitmap.
   bool IsMarked(const Object* object) const;
@@ -193,9 +205,6 @@
   static bool IsMarkedArrayCallback(const Object* object, void* arg)
       SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
 
-  static void MarkObjectVisitor(const Object* root, void* arg)
-      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
-
   static void ReMarkObjectVisitor(const Object* root, void* arg)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
 
@@ -417,6 +426,8 @@
   size_t array_count_;
   size_t other_count_;
 
+  UniquePtr<Barrier> gc_barrier_;
+
   friend class AddIfReachesAllocSpaceVisitor; // Used by mod-union table.
   friend class CheckBitmapVisitor;
   friend class CheckObjectVisitor;