src/share/vm/code/nmethod.cpp

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@@ -1178,18 +1178,21 @@
   // Set the traversal mark to ensure that the sweeper does 2
   // cleaning passes before moving to zombie.
   set_stack_traversal_mark(NMethodSweeper::traversal_count());
 }
 
-// Tell if a non-entrant method can be converted to a zombie (i.e., there is no activations on the stack)
+// Tell if a non-entrant method can be converted to a zombie (i.e.,
+// there are no activations on the stack, not in use by the VM,
+// and not in use by the ServiceThread)
 bool nmethod::can_not_entrant_be_converted() {
   assert(is_not_entrant(), "must be a non-entrant method");
 
   // Since the nmethod sweeper only does partial sweep the sweeper's traversal
   // count can be greater than the stack traversal count before it hits the
   // nmethod for the second time.
-  return stack_traversal_mark()+1 < NMethodSweeper::traversal_count();
+  return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
+         !is_locked_by_vm();
 }
 
 void nmethod::inc_decompile_count() {
   if (!is_compiled_by_c2()) return;
   // Could be gated by ProfileTraps, but do not bother...

@@ -1292,22 +1295,18 @@
 }
 
 // Common functionality for both make_not_entrant and make_zombie
 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
+  assert(!is_zombie(), "should not already be a zombie");
 
   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.
   nmethodLocker nml(this);
   methodHandle the_method(method());
   No_Safepoint_Verifier nsv;
 
   {
-    // If the method is already zombie there is nothing to do
-    if (is_zombie()) {
-      return false;
-    }
-
     // invalidate osr nmethod before acquiring the patching lock since
     // they both acquire leaf locks and we don't want a deadlock.
     // This logic is equivalent to the logic below for patching the
     // verified entry point of regular methods.
     if (is_osr_method()) {

@@ -1373,17 +1372,16 @@
       // dependency logic could have become stale.
       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
       flush_dependencies(NULL);
     }
 
-    {
-      // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload event
-      // and it hasn't already been reported for this nmethod then report it now.
-      // (the event may have been reported earilier if the GC marked it for unloading).
-      Pause_No_Safepoint_Verifier pnsv(&nsv);
+    // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload
+    // event and it hasn't already been reported for this nmethod then
+    // report it now. The event may have been reported earilier if the GC
+    // marked it for unloading). JvmtiDeferredEventQueue support means
+    // we no longer go to a safepoint here.
       post_compiled_method_unload();
-    }
 
 #ifdef ASSERT
     // It's no longer safe to access the oops section since zombie
     // nmethods aren't scanned for GC.
     _oops_are_stale = true;

@@ -1564,11 +1562,11 @@
   // it's being unloaded there's no way to look it up since the weak
   // ref will have been cleared.
   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {
     assert(!unload_reported(), "already unloaded");
     JvmtiDeferredEvent event =
-      JvmtiDeferredEvent::compiled_method_unload_event(
+      JvmtiDeferredEvent::compiled_method_unload_event(this,
           _jmethod_id, insts_begin());
     if (SafepointSynchronize::is_at_safepoint()) {
       // Don't want to take the queueing lock. Add it as pending and
       // it will get enqueued later.
       JvmtiDeferredEventQueue::add_pending_event(event);

@@ -2169,14 +2167,16 @@
   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");
   _nm = (nmethod*)cb;
   lock_nmethod(_nm);
 }
 
-void nmethodLocker::lock_nmethod(nmethod* nm) {
+// Only JvmtiDeferredEvent::compiled_method_unload_event()
+// should pass zombie_ok == true.
+void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {
   if (nm == NULL)  return;
   Atomic::inc(&nm->_lock_count);
-  guarantee(!nm->is_zombie(), "cannot lock a zombie method");
+  guarantee(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");
 }
 
 void nmethodLocker::unlock_nmethod(nmethod* nm) {
   if (nm == NULL)  return;
   Atomic::dec(&nm->_lock_count);