# HG changeset patch
# User brutisso
# Date 1454935137 -3600
#      Mon Feb 08 13:38:57 2016 +0100
# Node ID 1156d47e39377a477e0b2179faab2f1b62878e3e
# Parent  3472ec7733c2763ac323386aa697f0653d66bf3a
[mq]: hang

diff --git a/src/share/vm/gc/g1/concurrentMarkThread.cpp b/src/share/vm/gc/g1/concurrentMarkThread.cpp
--- a/src/share/vm/gc/g1/concurrentMarkThread.cpp
+++ b/src/share/vm/gc/g1/concurrentMarkThread.cpp
@@ -123,6 +123,7 @@
     // wait until started is set.
     sleepBeforeNextCycle();
     if (_should_terminate) {
+      _cm->root_regions()->cancel_scan();
       break;
     }
 
@@ -140,10 +141,9 @@
       // without the root regions have been scanned which would be a
       // correctness issue.
 
-      if (!cm()->has_aborted()) {
-        GCConcPhaseTimer(_cm, "Concurrent Root Region Scanning");
-        _cm->scanRootRegions();
-      }
+      assert(!cm()->has_aborted(), "Aborting before root region scanning is finished not supported.");
+      GCConcPhaseTimer(_cm, "Concurrent Root Region Scanning");
+      _cm->scanRootRegions();
 
       // It would be nice to use the GCTraceConcTime class here but
       // the "end" logging is inside the loop and not at the end of
diff --git a/src/share/vm/gc/g1/g1CollectedHeap.cpp b/src/share/vm/gc/g1/g1CollectedHeap.cpp
--- a/src/share/vm/gc/g1/g1CollectedHeap.cpp
+++ b/src/share/vm/gc/g1/g1CollectedHeap.cpp
@@ -1290,8 +1290,7 @@
       ref_processor_cm()->verify_no_references_recorded();
 
       // Abandon current iterations of concurrent marking and concurrent
-      // refinement, if any are in progress. We have to do this before
-      // wait_until_scan_finished() below.
+      // refinement, if any are in progress.
       concurrent_mark()->abort();
 
       // Make sure we'll choose a new allocation region afterwards.
diff --git a/src/share/vm/gc/g1/g1ConcurrentMark.cpp b/src/share/vm/gc/g1/g1ConcurrentMark.cpp
--- a/src/share/vm/gc/g1/g1ConcurrentMark.cpp
+++ b/src/share/vm/gc/g1/g1ConcurrentMark.cpp
@@ -372,6 +372,12 @@
   return res;
 }
 
+void G1CMRootRegions::cancel_scan() {
+  MutexLockerEx x(RootRegionScan_lock, Mutex::_no_safepoint_check_flag);
+  _scan_in_progress = false;
+  RootRegionScan_lock->notify_all();
+}
+
 void G1CMRootRegions::scan_finished() {
   assert(scan_in_progress(), "pre-condition");
 
diff --git a/src/share/vm/gc/g1/g1ConcurrentMark.hpp b/src/share/vm/gc/g1/g1ConcurrentMark.hpp
--- a/src/share/vm/gc/g1/g1ConcurrentMark.hpp
+++ b/src/share/vm/gc/g1/g1ConcurrentMark.hpp
@@ -248,6 +248,8 @@
   // all have been claimed.
   HeapRegion* claim_next();
 
+  void cancel_scan();
+
   // Flag that we're done with root region scanning and notify anyone
   // who's waiting on it. If aborted is false, assume that all regions
   // have been claimed.
# HG changeset patch
# User brutisso
# Date 1454940301 -3600
#      Mon Feb 08 15:05:01 2016 +0100
# Node ID 0888bb4acd9cadfa245845cc043343736b130634
# Parent  1156d47e39377a477e0b2179faab2f1b62878e3e
[mq]: if-assert

diff --git a/src/share/vm/gc/g1/concurrentMarkThread.cpp b/src/share/vm/gc/g1/concurrentMarkThread.cpp
--- a/src/share/vm/gc/g1/concurrentMarkThread.cpp
+++ b/src/share/vm/gc/g1/concurrentMarkThread.cpp
@@ -141,9 +141,11 @@
       // without the root regions have been scanned which would be a
       // correctness issue.
 
-      assert(!cm()->has_aborted(), "Aborting before root region scanning is finished not supported.");
-      GCConcPhaseTimer(_cm, "Concurrent Root Region Scanning");
-      _cm->scanRootRegions();
+      if (_cm->root_regions()->scan_in_progress()) {
+        assert(!cm()->has_aborted(), "Aborting before root region scanning is finished not supported.");
+        GCConcPhaseTimer(_cm, "Concurrent Root Region Scanning");
+        _cm->scanRootRegions();
+      }
 
       // It would be nice to use the GCTraceConcTime class here but
       // the "end" logging is inside the loop and not at the end of
diff --git a/src/share/vm/gc/g1/g1ConcurrentMark.cpp b/src/share/vm/gc/g1/g1ConcurrentMark.cpp
--- a/src/share/vm/gc/g1/g1ConcurrentMark.cpp
+++ b/src/share/vm/gc/g1/g1ConcurrentMark.cpp
@@ -372,12 +372,16 @@
   return res;
 }
 
-void G1CMRootRegions::cancel_scan() {
+void G1CMRootRegions::notify_scan_done() {
   MutexLockerEx x(RootRegionScan_lock, Mutex::_no_safepoint_check_flag);
   _scan_in_progress = false;
   RootRegionScan_lock->notify_all();
 }
 
+void G1CMRootRegions::cancel_scan() {
+  notify_scan_done();
+}
+
 void G1CMRootRegions::scan_finished() {
   assert(scan_in_progress(), "pre-condition");
 
@@ -387,11 +391,7 @@
   }
   _next_survivor = NULL;
 
-  {
-    MutexLockerEx x(RootRegionScan_lock, Mutex::_no_safepoint_check_flag);
-    _scan_in_progress = false;
-    RootRegionScan_lock->notify_all();
-  }
+  notify_scan_done();
 }
 
 bool G1CMRootRegions::wait_until_scan_finished() {
diff --git a/src/share/vm/gc/g1/g1ConcurrentMark.hpp b/src/share/vm/gc/g1/g1ConcurrentMark.hpp
--- a/src/share/vm/gc/g1/g1ConcurrentMark.hpp
+++ b/src/share/vm/gc/g1/g1ConcurrentMark.hpp
@@ -229,6 +229,8 @@
   volatile bool        _should_abort;
   HeapRegion* volatile _next_survivor;
 
+  void notify_scan_done();
+
 public:
   G1CMRootRegions();
   // We actually do most of the initialization in this method.