--- old/src/share/vm/gc/g1/concurrentMarkThread.cpp	2015-06-23 11:13:44.275875979 +0200
+++ new/src/share/vm/gc/g1/concurrentMarkThread.cpp	2015-06-23 11:13:44.155875984 +0200
@@ -79,11 +79,11 @@
 };
 
 // We want to avoid that the logging from the concurrent thread is mixed
-// with the logging from a STW GC. Join the STS to ensure that the logging
-// is done either before or after the STW logging.
-void ConcurrentMarkThread::cm_log(bool doit, const char* fmt, ...) {
+// with the logging from a STW GC. So, if necessary join the STS to ensure
+// that the logging is done either before or after the STW logging.
+void ConcurrentMarkThread::cm_log(bool doit, bool join_sts, const char* fmt, ...) {
   if (doit) {
-    SuspendibleThreadSetJoiner sts_joiner;
+    SuspendibleThreadSetJoiner sts_joiner(join_sts);
     va_list args;
     va_start(args, fmt);
     gclog_or_tty->gclog_stamp(cm()->concurrent_gc_id());
@@ -121,28 +121,18 @@
       // subsequent GC could block us from joining the STS and proceed
       // without the root regions have been scanned which would be a
       // correctness issue.
-      // This means that we can not use the cm_log() method for the logging
-      // regarding the root region scanning below.
 
       double scan_start = os::elapsedTime();
       if (!cm()->has_aborted()) {
-        if (G1Log::fine()) {
-          gclog_or_tty->gclog_stamp(cm()->concurrent_gc_id());
-          gclog_or_tty->print_cr("[GC concurrent-root-region-scan-start]");
-        }
+        cm_log(G1Log::fine(), false, "[GC concurrent-root-region-scan-start]");
 
         _cm->scanRootRegions();
 
-        double scan_end = os::elapsedTime();
-        if (G1Log::fine()) {
-          gclog_or_tty->gclog_stamp(cm()->concurrent_gc_id());
-          gclog_or_tty->print_cr("[GC concurrent-root-region-scan-end, %1.7lf secs]",
-                                 scan_end - scan_start);
-        }
+        cm_log(G1Log::fine(), false, "[GC concurrent-root-region-scan-end, %1.7lf secs]", os::elapsedTime() - scan_start);
       }
 
       double mark_start_sec = os::elapsedTime();
-      cm_log(G1Log::fine(), "[GC concurrent-mark-start]");
+      cm_log(G1Log::fine(), true, "[GC concurrent-mark-start]");
 
       int iter = 0;
       do {
@@ -162,15 +152,15 @@
             os::sleep(current_thread, sleep_time_ms, false);
           }
 
-          cm_log(G1Log::fine(), "[GC concurrent-mark-end, %1.7lf secs]", mark_end_sec - mark_start_sec);
+          cm_log(G1Log::fine(), true, "[GC concurrent-mark-end, %1.7lf secs]", mark_end_sec - mark_start_sec);
 
           CMCheckpointRootsFinalClosure final_cl(_cm);
           VM_CGC_Operation op(&final_cl, "GC remark", true /* needs_pll */);
           VMThread::execute(&op);
         }
         if (cm()->restart_for_overflow()) {
-          cm_log(G1TraceMarkStackOverflow, "Restarting conc marking because of MS overflow in remark (restart #%d).", iter);
-          cm_log(G1Log::fine(), "[GC concurrent-mark-restart-for-overflow]");
+          cm_log(G1TraceMarkStackOverflow, true, "Restarting conc marking because of MS overflow in remark (restart #%d).", iter);
+          cm_log(G1Log::fine(), true, "[GC concurrent-mark-restart-for-overflow]");
         }
       } while (cm()->restart_for_overflow());
 
@@ -210,7 +200,7 @@
         // reclaimed by cleanup.
 
         double cleanup_start_sec = os::elapsedTime();
-        cm_log(G1Log::fine(), "[GC concurrent-cleanup-start]");
+        cm_log(G1Log::fine(), true, "[GC concurrent-cleanup-start]");
 
         // Now do the concurrent cleanup operation.
         _cm->completeCleanup();
@@ -227,7 +217,7 @@
         g1h->reset_free_regions_coming();
 
         double cleanup_end_sec = os::elapsedTime();
-        cm_log(G1Log::fine(), "[GC concurrent-cleanup-end, %1.7lf secs]", cleanup_end_sec - cleanup_start_sec);
+        cm_log(G1Log::fine(), true, "[GC concurrent-cleanup-end, %1.7lf secs]", cleanup_end_sec - cleanup_start_sec);
       }
       guarantee(cm()->cleanup_list_is_empty(),
                 "at this point there should be no regions on the cleanup list");
@@ -261,10 +251,7 @@
         if (!cm()->has_aborted()) {
           g1_policy->record_concurrent_mark_cleanup_completed();
         } else {
-          if (G1Log::fine()) {
-            gclog_or_tty->gclog_stamp(cm()->concurrent_gc_id());
-            gclog_or_tty->print_cr("[GC concurrent-mark-abort]");
-          }
+          cm_log(G1Log::fine(), false, "[GC concurrent-mark-abort]");
         }
       }