From 6306dce8314bc82d7bf3cb7a3b3a53ff7440ed2f Mon Sep 17 00:00:00 2001
From: Stefan Johansson <sjohanss@openjdk.org>
Date: Thu, 30 Oct 2014 10:51:06 +0100
Subject: [PATCH] 8061234: ResourceContext.requestAccurateUpdate() is
 unreliable

Changing copy_allocation_context_stats to return if there are more stats available after the copy.

Reviewed-by: rriggs, jcoomes
---
 .../src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp  | 2 +-
 .../share/vm/gc_implementation/g1/g1CollectedHeap_ext.cpp  | 3 ++-
 hotspot/src/share/vm/gc_interface/collectedHeap.hpp        | 7 +++++--
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
index f1aaceaacb4..e7ff5d4b016 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
@@ -1248,7 +1248,7 @@ public:
   // The same as above but assume that the caller holds the Heap_lock.
   void collect_locked(GCCause::Cause cause);
 
-  virtual void copy_allocation_context_stats(const jint* contexts,
+  virtual bool copy_allocation_context_stats(const jint* contexts,
                                              jlong* totals,
                                              jbyte* accuracy,
                                              jint len);
diff --git a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap_ext.cpp b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap_ext.cpp
index 401b28b6fee..7f71451b6ca 100644
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap_ext.cpp
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap_ext.cpp
@@ -25,8 +25,9 @@
 #include "precompiled.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.hpp"
 
-void G1CollectedHeap::copy_allocation_context_stats(const jint* contexts,
+bool G1CollectedHeap::copy_allocation_context_stats(const jint* contexts,
                                                     jlong* totals,
                                                     jbyte* accuracy,
                                                     jint len) {
+  return false;
 }
diff --git a/hotspot/src/share/vm/gc_interface/collectedHeap.hpp b/hotspot/src/share/vm/gc_interface/collectedHeap.hpp
index ea2dcc9a54b..bbd778c3463 100644
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.hpp
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.hpp
@@ -644,10 +644,13 @@ class CollectedHeap : public CHeapObj<mtInternal> {
   // For each context in contexts, set the corresponding entries in the totals
   // and accuracy arrays to the current values held by the statistics.  Each
   // array should be of length len.
-  virtual void copy_allocation_context_stats(const jint* contexts,
+  // Returns true if there are more stats available.
+  virtual bool copy_allocation_context_stats(const jint* contexts,
                                              jlong* totals,
                                              jbyte* accuracy,
-                                             jint len) { }
+                                             jint len) {
+    return false;
+  }
 
   /////////////// Unit tests ///////////////