# HG changeset patch
# User Yasumasa Suenaga  <yasuenag@gmail.com>
# Date 1413552547 -32400
# Node ID f2220f6e86b7449de94a73baa2e7a8ef6f32cb3a
# Parent  496fc55ddc329d04954ee0952b73da3f3c56cdbf
Bug 2017: JVM may crash with taking interval SnapShot when concurrent GC is occurred.
reviewed-by: ykubota

diff -r 496fc55ddc32 -r f2220f6e86b7 agent/ChangeLog
--- a/agent/ChangeLog	Fri Aug 22 10:18:27 2014 +0900
+++ b/agent/ChangeLog	Fri Oct 17 22:29:07 2014 +0900
@@ -1,3 +1,7 @@
+2014-10-17  KUBOTA Yuji  <yasuenag@gmail.com>
+
+	* Bug 2017: JVM may crash with taking interval SnapShot when concurrent GC is occurred.
+
 2014-08-22  KUBOTA Yuji  <kubota.yuji@lab.ntt.co.jp>
 
 	* Bump to 1.0.3
diff -r 496fc55ddc32 -r f2220f6e86b7 agent/src/oopUtil.cpp
--- a/agent/src/oopUtil.cpp	Fri Aug 22 10:18:27 2014 +0900
+++ b/agent/src/oopUtil.cpp	Fri Oct 17 22:29:07 2014 +0900
@@ -2349,12 +2349,24 @@
   }
   
   if(useG1){
+
     if(unlikely(!jvmInfo->isAfterCR7046558())){
       /* Heapstats agent is unsupported G1GC on JDK6. */
       PRINT_CRIT_MSG("Sorry, G1GC isn't supported in this HotSpot version.");
       PRINT_CRIT_MSG("You should use >= 22.0-b03");
       return false;
     }
+
+    if(arg.TimerInterval > 0){
+      PRINT_WARN_MSG("Interval SnapShot is not supported with G1GC. Turn off.");
+      arg.TimerInterval = 0;
+    }
+
+    if(arg.triggerOnDump){
+      PRINT_WARN_MSG("SnapShot trigger on dump request is not supported with G1GC. Turn off.");
+      arg.triggerOnDump = false;
+    }
+
   }
 
   return true;
diff -r 496fc55ddc32 -r f2220f6e86b7 agent/src/oopUtil.hpp
--- a/agent/src/oopUtil.hpp	Fri Aug 22 10:18:27 2014 +0900
+++ b/agent/src/oopUtil.hpp	Fri Oct 17 22:29:07 2014 +0900
@@ -190,6 +190,15 @@
 extern "C" bool useG1;
 
 /*!
+ * \brief CMS collector state pointer.
+ * \sa concurrentMarkSweepGeneration.hpp<br>
+ *     at hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/<br>
+ *     enum CollectorState
+ */
+extern int *CMS_collectorState;
+
+
+/*!
  * \brief JVM safepoint state pointer.
  */
 extern "C" int *safePointState;
diff -r 496fc55ddc32 -r f2220f6e86b7 agent/src/snapShotMain.cpp
--- a/agent/src/snapShotMain.cpp	Fri Aug 22 10:18:27 2014 +0900
+++ b/agent/src/snapShotMain.cpp	Fri Oct 17 22:29:07 2014 +0900
@@ -449,6 +449,12 @@
  *                   e.g. GC, DumpRequest or Interval.
  */
 void TakeSnapShot(jvmtiEnv *jvmti, JNIEnv *env, TInvokeCause cause) {
+
+  if(useCMS && (*CMS_collectorState > CMS_IDLING)){
+    PRINT_WARN_MSG("CMS GC is working. Skip to take a SnapShot.");
+    return;
+  }
+
   /* Count working time. */
   static const char *label = "Take SnapShot";
   TElapsedTimer elapsedTime(label);