# HG changeset patch
# User rkennke
# Date 1494496867 -7200
#      Thu May 11 12:01:07 2017 +0200
# Node ID 4038129566dbee7c893d1040eff3564d6d2f2f30
# Parent  74fad78c5957ba3fe3c8b4a5ac434a9e93872e9f
8180175: ObjectSynchronizer only needs to iterate in-use monitors

diff --git a/src/share/vm/runtime/synchronizer.cpp b/src/share/vm/runtime/synchronizer.cpp
--- a/src/share/vm/runtime/synchronizer.cpp
+++ b/src/share/vm/runtime/synchronizer.cpp
@@ -964,6 +964,14 @@
 
 
 void ObjectSynchronizer::oops_do(OopClosure* f) {
+  if (MonitorInUseLists) {
+    global_used_oops_do(f);
+  } else {
+    global_oops_do(f);
+  }
+}
+
+void ObjectSynchronizer::global_oops_do(OopClosure* f) {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
   PaddedEnd<ObjectMonitor> * block =
     (PaddedEnd<ObjectMonitor> *)OrderAccess::load_ptr_acquire(&gBlockList);
@@ -978,6 +986,26 @@
   }
 }
 
+void ObjectSynchronizer::global_used_oops_do(OopClosure* f) {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+  list_oops_do(gOmInUseList, f);
+}
+
+void ObjectSynchronizer::thread_local_used_oops_do(Thread* thread, OopClosure* f) {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+  list_oops_do(thread->omInUseList, f);
+}
+
+void ObjectSynchronizer::list_oops_do(ObjectMonitor* list, OopClosure* f) {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+  ObjectMonitor* mid;
+  for (mid = list; mid != NULL; mid = mid->FreeNext) {
+    if (mid->object() != NULL) {
+      f->do_oop((oop*)mid->object_addr());
+    }
+  }
+}
+
 
 // -----------------------------------------------------------------------------
 // ObjectMonitor Lifecycle
diff --git a/src/share/vm/runtime/synchronizer.hpp b/src/share/vm/runtime/synchronizer.hpp
--- a/src/share/vm/runtime/synchronizer.hpp
+++ b/src/share/vm/runtime/synchronizer.hpp
@@ -136,6 +136,7 @@
                               ObjectMonitor** freeHeadp,
                               ObjectMonitor** freeTailp);
   static void oops_do(OopClosure* f);
+  static void thread_local_used_oops_do(Thread* thread, OopClosure* f);
 
   // debugging
   static void sanity_checks(const bool verbose,
@@ -156,6 +157,11 @@
   static ObjectMonitor * volatile gOmInUseList;
   // count of entries in gOmInUseList
   static int gOmInUseCount;
+
+  static void global_oops_do(OopClosure* f);
+  static void global_used_oops_do(OopClosure* f);
+  static void list_oops_do(ObjectMonitor* list, OopClosure* f);
+
 };
 
 // ObjectLocker enforced balanced locking and can never thrown an
diff --git a/src/share/vm/runtime/thread.cpp b/src/share/vm/runtime/thread.cpp
--- a/src/share/vm/runtime/thread.cpp
+++ b/src/share/vm/runtime/thread.cpp
@@ -792,6 +792,10 @@
   // Do oop for ThreadShadow
   f->do_oop((oop*)&_pending_exception);
   handle_area()->oops_do(f);
+
+  if (MonitorInUseLists) {
+    ObjectSynchronizer::thread_local_used_oops_do(this, f);
+  }
 }
 
 void Thread::metadata_handles_do(void f(Metadata*)) {