# HG changeset patch
# User coleenp
# Date 1292001183 18000
# Node ID 7cf1a74771e8c92c7f44ac1634685d6808898cca
# Parent  a5610f0862fe5c66a89db4e3f843599d50a229a4
6988439: Parallel Class Loading test deadlock involving MethodData_lock and Pending List Lock
Summary: Don't acquire methodData_lock while holding pending list lock
Reviewed-by: kvn, never, ysr

diff -r a5610f0862fe -r 7cf1a74771e8 src/share/vm/oops/instanceRefKlass.cpp
--- a/src/share/vm/oops/instanceRefKlass.cpp	Thu Dec 09 20:12:06 2010 -0500
+++ b/src/share/vm/oops/instanceRefKlass.cpp	Fri Dec 10 12:13:03 2010 -0500
@@ -457,6 +457,11 @@
   }
 }
 
+bool instanceRefKlass::owns_pending_list_lock(JavaThread* thread) {
+  Handle h_lock(thread, java_lang_ref_Reference::pending_list_lock());
+  return ObjectSynchronizer::current_thread_holds_lock(thread, h_lock);
+}
+
 void instanceRefKlass::acquire_pending_list_lock(BasicLock *pending_list_basic_lock) {
   // we may enter this with pending exception set
   PRESERVE_EXCEPTION_MARK;  // exceptions are never thrown, needed for TRAPS argument
diff -r a5610f0862fe -r 7cf1a74771e8 src/share/vm/oops/instanceRefKlass.hpp
--- a/src/share/vm/oops/instanceRefKlass.hpp	Thu Dec 09 20:12:06 2010 -0500
+++ b/src/share/vm/oops/instanceRefKlass.hpp	Fri Dec 10 12:13:03 2010 -0500
@@ -89,6 +89,7 @@
 
   static void release_and_notify_pending_list_lock(BasicLock *pending_list_basic_lock);
   static void acquire_pending_list_lock(BasicLock *pending_list_basic_lock);
+  static bool owns_pending_list_lock(JavaThread* thread);
 
   // Update non-static oop maps so 'referent', 'nextPending' and
   // 'discovered' will look like non-oops
diff -r a5610f0862fe -r 7cf1a74771e8 src/share/vm/oops/methodOop.cpp
--- a/src/share/vm/oops/methodOop.cpp	Thu Dec 09 20:12:06 2010 -0500
+++ b/src/share/vm/oops/methodOop.cpp	Fri Dec 10 12:13:03 2010 -0500
@@ -309,6 +309,12 @@
 // Build a methodDataOop object to hold information about this method
 // collected in the interpreter.
 void methodOopDesc::build_interpreter_method_data(methodHandle method, TRAPS) {
+  // Do not profile method if current thread holds the pending list lock,
+  // which avoids deadlock for acquiring the MethodData_lock.
+  if (instanceRefKlass::owns_pending_list_lock((JavaThread*)THREAD)) {
+    return;
+  }
+
   // Grab a lock here to prevent multiple
   // methodDataOops from being created.
   MutexLocker ml(MethodData_lock, THREAD);