src/share/vm/gc_implementation/g1/vm_operations_g1.cpp

rev 2755 : 7099824: G1: we should take the pending list lock before doing the remark pause
Summary: Acquire the pending list lock in the prologue method of G1's
concurrent VM_Operation and release the lock in the epilogue() method.
The locking/unlocking order of the pending list lock and the Heap_lock
should match that in the prologue and epilogue methods of VM_GC_Operation.
Reviewed-by:

@@ -21,10 +21,11 @@
  * questions.
  *
  */
 
 #include "precompiled.hpp"
+#include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
 #include "gc_implementation/g1/vm_operations_g1.hpp"
 #include "gc_implementation/shared/isGCActiveMark.hpp"
 #include "gc_implementation/g1/vm_operations_g1.hpp"

@@ -163,10 +164,24 @@
       }
     }
   }
 }
 
+void VM_CGC_Operation::acquire_pending_list_lock() {
+  // The caller may block while communicating
+  // with the SLT thread in order to acquire/release the PLL.
+  ConcurrentMarkThread::slt()->
+    manipulatePLL(SurrogateLockerThread::acquirePLL);
+}
+
+void VM_CGC_Operation::release_and_notify_pending_list_lock() {
+  // The caller may block while communicating
+  // with the SLT thread in order to acquire/release the PLL.
+  ConcurrentMarkThread::slt()->
+    manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
+}
+
 void VM_CGC_Operation::doit() {
   gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
   TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
   TraceTime t(_printGCMessage, PrintGC, true, gclog_or_tty);
   SharedHeap* sh = SharedHeap::heap();

@@ -178,14 +193,21 @@
     _cl->do_void();
   }
 }
 
 bool VM_CGC_Operation::doit_prologue() {
+  // Note the relative order of the locks must match that in
+  // VM_GC_Operation::doit_prologue() or deadlocks can occur
+  acquire_pending_list_lock();
+
   Heap_lock->lock();
   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
   return true;
 }
 
 void VM_CGC_Operation::doit_epilogue() {
+  // Note the relative order of the unlocks must match that in
+  // VM_GC_Operation::doit_epilogue()
   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
   Heap_lock->unlock();
+  release_and_notify_pending_list_lock();
 }