commit 78f7b4c04ab6e8b5581921bc95b67a9beee1c246
author Mathieu Chartier <mathieuc@google.com> Tue May 06 10:57:27 2014 -0700
committer Mathieu Chartier <mathieuc@google.com> Wed May 07 15:28:35 2014 -0700
tree 78b93c72007478b5bfc3b88ab413fa3d772da723
parent 052a647973b590c9d5007a2e16f313f4e32a70bd

Add concurrent reference processing.

Concurrent reference processing currently works by going into native
code from java.lang.ref.Reference.get(). From there, we have a fast
path if the references aren't being processed which returns the
referent without needing to access any locks. In the slow path we
block until reference processing is complete. It may be possible to
improve the slow path if the referent is blackened.

TODO: Investigate doing the fast path in java code by using racy reads
of a static volatile boolean. This will work as long as there are no
suspend points inbetween the boolean read and referent read.

Bug: 14381653

Change-Id: I1546b55be4691fe4ff4aa6d857b234cce7187d87

runtime/gc/collector/mark_sweep.h

diff --git a/runtime/gc/collector/mark_sweep.h b/runtime/gc/collector/mark_sweep.h
index bfc70d1..3ebc0af 100644
--- a/runtime/gc/collector/mark_sweep.h
+++ b/runtime/gc/collector/mark_sweep.h
@@ -123,10 +123,6 @@
   void ProcessReferences(Thread* self)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-  void PreProcessReferences()
-      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
-      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-
   // Update and mark references from immune spaces.
   void UpdateAndMarkModUnion()
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -191,8 +187,9 @@
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
 
-  static void ProcessMarkStackPausedCallback(void* arg)
-      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_);
+  static void ProcessMarkStackCallback(void* arg)
+      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   static void MarkRootParallelCallback(mirror::Object** root, void* arg, uint32_t thread_id,
                                        RootType root_type)