commit bb87e0f1a52de656bc77cb01cb887e51a0e5198b
author Mathieu Chartier <mathieuc@google.com> Fri Apr 03 11:21:55 2015 -0700
committer Mathieu Chartier <mathieuc@google.com> Mon Apr 06 10:44:37 2015 -0700
tree 113f014c6e20fab3e936a3ac05f9f738639541f6
parent e57fc0f0260fcb1d08cbb720ec95c04c0f394b91

Refactor and improve GC root handling

Changed GcRoot to use compressed references. Changed root visiting to
use virtual functions instead of function pointers. Changed root visting
interface to be an array of roots instead of a single root at a time.
Added buffered root marking helper to avoid dispatch overhead.

Root marking seems a bit faster on EvaluateAndApplyChanges due to batch
marking. Pause times unaffected.

Mips64 is untested but might work, maybe.

Before:
MarkConcurrentRoots: Sum: 67.678ms 99% C.I. 2us-664.999us Avg: 161.138us Max: 671us

After:
MarkConcurrentRoots: Sum: 54.806ms 99% C.I. 2us-499.986us Avg: 136.333us Max: 602us

Bug: 19264997

Change-Id: I0a71ebb5928f205b9b3f7945b25db6489d5657ca

runtime/transaction.h

diff --git a/runtime/transaction.h b/runtime/transaction.h
index 1419a38..4d85662 100644
--- a/runtime/transaction.h
+++ b/runtime/transaction.h
@@ -100,7 +100,7 @@
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(log_lock_);
 
-  void VisitRoots(RootCallback* callback, void* arg)
+  void VisitRoots(RootVisitor* visitor)
       LOCKS_EXCLUDED(log_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
@@ -116,7 +116,7 @@
     void LogReferenceValue(MemberOffset offset, mirror::Object* obj, bool is_volatile);
 
     void Undo(mirror::Object* obj) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-    void VisitRoots(RootCallback* callback, void* arg);
+    void VisitRoots(RootVisitor* visitor) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
     size_t Size() const {
       return field_values_.size();
@@ -184,7 +184,7 @@
     void Undo(InternTable* intern_table)
         SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
         EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_);
-    void VisitRoots(RootCallback* callback, void* arg);
+    void VisitRoots(RootVisitor* visitor) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
    private:
     mirror::String* str_;
@@ -207,13 +207,13 @@
       EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-  void VisitObjectLogs(RootCallback* callback, void* arg)
+  void VisitObjectLogs(RootVisitor* visitor)
       EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  void VisitArrayLogs(RootCallback* callback, void* arg)
+  void VisitArrayLogs(RootVisitor* visitor)
       EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
-  void VisitStringLogs(RootCallback* callback, void* arg)
+  void VisitStringLogs(RootVisitor* visitor)
       EXCLUSIVE_LOCKS_REQUIRED(log_lock_)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);