From 5ffa0780a2738eed1f86efb967ea99badcbd5d9c Mon Sep 17 00:00:00 2001
From: Mathieu Chartier <mathieuc@google.com>
Date: Wed, 27 Jul 2016 10:45:47 -0700
Subject: Reduce unnecessary read barriers in GC

Removed read barrier from IsUnprocessed, DequeuePendingReference,
EnqueueReference, and a few other places.

Hard to tell if GC time goes down.

EAAC:
Before GC slow path count: 254857
After GC slow path count: 1005

Bug: 30162165
Bug: 12687968

Test: test-art-host, volantis boot with CC

Change-Id: Ic2add3a9b1e1d7561b0b167f2218b10f8dbff76c
---
 runtime/mirror/reference.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'runtime/mirror/reference.h')

diff --git a/runtime/mirror/reference.h b/runtime/mirror/reference.h
index 3baa12e40b..e8ad5fa1c8 100644
--- a/runtime/mirror/reference.h
+++ b/runtime/mirror/reference.h
@@ -76,8 +76,9 @@ class MANAGED Reference : public Object {
     SetFieldObjectVolatile<kTransactionActive>(ReferentOffset(), nullptr);
   }
 
+  template <ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
   Reference* GetPendingNext() SHARED_REQUIRES(Locks::mutator_lock_) {
-    return GetFieldObject<Reference>(PendingNextOffset());
+    return GetFieldObject<Reference, kDefaultVerifyFlags, kReadBarrierOption>(PendingNextOffset());
   }
 
   void SetPendingNext(Reference* pending_next)
@@ -102,7 +103,7 @@ class MANAGED Reference : public Object {
   // removed from the list after having determined the reference is not ready
   // to be enqueued on a java ReferenceQueue.
   bool IsUnprocessed() SHARED_REQUIRES(Locks::mutator_lock_) {
-    return GetPendingNext() == nullptr;
+    return GetPendingNext<kWithoutReadBarrier>() == nullptr;
   }
 
   template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
-- 
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