1.1 --- a/src/share/vm/code/nmethod.hpp Tue Mar 15 06:35:10 2011 -0700
1.2 +++ b/src/share/vm/code/nmethod.hpp Tue Mar 15 06:37:31 2011 -0700
1.3 @@ -194,7 +194,10 @@
1.4
1.5 NOT_PRODUCT(bool _has_debug_info; )
1.6
1.7 - // Nmethod Flushing lock (if non-zero, then the nmethod is not removed)
1.8 + // Nmethod Flushing lock. If non-zero, then the nmethod is not removed
1.9 + // and is not made into a zombie. However, once the nmethod is made into
1.10 + // a zombie, it will be locked one final time if CompiledMethodUnload
1.11 + // event processing needs to be done.
1.12 jint _lock_count;
1.13
1.14 // not_entrant method removal. Each mark_sweep pass will update
1.15 @@ -522,8 +525,9 @@
1.16 void flush();
1.17
1.18 public:
1.19 - // If returning true, it is unsafe to remove this nmethod even though it is a zombie
1.20 - // nmethod, since the VM might have a reference to it. Should only be called from a safepoint.
1.21 + // When true is returned, it is unsafe to remove this nmethod even if
1.22 + // it is a zombie, since the VM or the ServiceThread might still be
1.23 + // using it.
1.24 bool is_locked_by_vm() const { return _lock_count >0; }
1.25
1.26 // See comment at definition of _last_seen_on_stack
1.27 @@ -689,13 +693,20 @@
1.28
1.29 };
1.30
1.31 -// Locks an nmethod so its code will not get removed, even if it is a zombie/not_entrant method
1.32 +// Locks an nmethod so its code will not get removed and it will not
1.33 +// be made into a zombie, even if it is a not_entrant method. After the
1.34 +// nmethod becomes a zombie, if CompiledMethodUnload event processing
1.35 +// needs to be done, then lock_nmethod() is used directly to keep the
1.36 +// generated code from being reused too early.
1.37 class nmethodLocker : public StackObj {
1.38 nmethod* _nm;
1.39
1.40 public:
1.41
1.42 - static void lock_nmethod(nmethod* nm); // note: nm can be NULL
1.43 + // note: nm can be NULL
1.44 + // Only JvmtiDeferredEvent::compiled_method_unload_event()
1.45 + // should pass zombie_ok == true.
1.46 + static void lock_nmethod(nmethod* nm, bool zombie_ok = false);
1.47 static void unlock_nmethod(nmethod* nm); // (ditto)
1.48
1.49 nmethodLocker(address pc); // derive nm from pc
