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src/hotspot/share/runtime/objectMonitor.hpp
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rev 59376 : 8153224.v2.10.patch merged with 8153224.v2.11.patch.
rev 59377 : CR1 changes from dcubed, dholmes, eosterlund and rehn.
@@ -134,17 +134,25 @@
// The sync code expects the header field to be at offset zero (0).
// Enforced by the assert() in header_addr().
volatile markWord _header; // displaced object header word - mark
void* volatile _object; // backward object pointer - strong root
- private:
+ typedef enum {
+ Free = 0, // Free must be 0 for monitor to be free after memset(..,0,..).
+ New,
+ Old
+ } AllocationState;
+ AllocationState _allocation_state;
// Separate _header and _owner on different cache lines since both can
- // have busy multi-threaded access. _header and _object are set at
- // initial inflation and _object doesn't change until deflation so
- // _object is a good choice to share the cache line with _header.
- DEFINE_PAD_MINUS_SIZE(0, OM_CACHE_LINE_SIZE,
- sizeof(volatile markWord) + sizeof(void* volatile));
+ // have busy multi-threaded access. _header, _object and _allocation_state
+ // are set at initial inflation. _object and _allocation_state don't
+ // change until deflation so _object and _allocation_state are good
+ // choices to share the cache line with _header.
+ DEFINE_PAD_MINUS_SIZE(0, OM_CACHE_LINE_SIZE, sizeof(volatile markWord) +
+ sizeof(void* volatile) + sizeof(AllocationState));
+ // Used by async deflation as a marker in the _owner field:
+ #define DEFLATER_MARKER reinterpret_cast<void*>(-1)
void* volatile _owner; // pointer to owning thread OR BasicLock
volatile jlong _previous_owner_tid; // thread id of the previous owner of the monitor
// Separate _owner and _next_om on different cache lines since
// both can have busy multi-threaded access. _previous_owner_tid is only
// changed by ObjectMonitor::exit() so it is a good choice to share the
@@ -162,13 +170,14 @@
Thread* volatile _Responsible;
volatile int _Spinner; // for exit->spinner handoff optimization
volatile int _SpinDuration;
- volatile jint _contentions; // Number of active contentions in enter(). It is used by is_busy()
+ jint _contentions; // Number of active contentions in enter(). It is used by is_busy()
// along with other fields to determine if an ObjectMonitor can be
- // deflated. See ObjectSynchronizer::deflate_monitor().
+ // deflated. It is also used by the async deflation protocol. See
+ // ObjectSynchronizer::deflate_monitor() and deflate_monitor_using_JT().
protected:
ObjectWaiter* volatile _WaitSet; // LL of threads wait()ing on the monitor
volatile jint _waiters; // number of waiting threads
private:
volatile int _WaitSetLock; // protects Wait Queue - simple spinlock
@@ -231,21 +240,38 @@
volatile markWord* header_addr();
void set_header(markWord hdr);
intptr_t is_busy() const {
// TODO-FIXME: assert _owner == null implies _recursions = 0
- return _contentions|_waiters|intptr_t(_owner)|intptr_t(_cxq)|intptr_t(_EntryList);
+ intptr_t ret_code = _waiters | intptr_t(_cxq) | intptr_t(_EntryList);
+ if (!AsyncDeflateIdleMonitors) {
+ ret_code |= contentions() | intptr_t(_owner);
+ } else {
+ if (contentions() > 0) {
+ ret_code |= contentions();
+ }
+ if (_owner != DEFLATER_MARKER) {
+ ret_code |= intptr_t(_owner);
+ }
+ }
+ return ret_code;
}
const char* is_busy_to_string(stringStream* ss);
intptr_t is_entered(Thread* current) const;
- void* owner() const;
+ void* owner() const; // Returns NULL if DEFLATER_MARKER is observed.
+ // Returns true if owner field == DEFLATER_MARKER and false otherwise.
+ bool owner_is_DEFLATER_MARKER();
+ // Returns true if 'this' is being async deflated and false otherwise.
+ bool is_being_async_deflated();
// Clear _owner field; current value must match old_value.
void release_clear_owner(void* old_value);
// Simply set _owner field to new_value; current value must match old_value.
void set_owner_from(void* old_value, void* new_value);
+ // Simply set _owner field to new_value; current value must match old_value1 or old_value2.
+ void set_owner_from(void* old_value1, void* old_value2, void* new_value);
// Simply set _owner field to self; current value must match basic_lock_p.
void set_owner_from_BasicLock(void* basic_lock_p, Thread* self);
// Try to set _owner field to new_value if the current value matches
// old_value, using Atomic::cmpxchg(). Otherwise, does not change the
// _owner field. Returns the prior value of the _owner field.
@@ -260,10 +286,11 @@
ObjectMonitor* try_set_next_om(ObjectMonitor* old_value, ObjectMonitor* new_value);
jint waiters() const;
jint contentions() const;
+ void add_to_contentions(jint value);
intx recursions() const { return _recursions; }
// JVM/TI GetObjectMonitorUsage() needs this:
ObjectWaiter* first_waiter() { return _WaitSet; }
ObjectWaiter* next_waiter(ObjectWaiter* o) { return o->_next; }
@@ -284,11 +311,13 @@
void Recycle() {
// TODO: add stronger asserts ...
// _cxq == 0 _succ == NULL _owner == NULL _waiters == 0
// _contentions == 0 EntryList == NULL
// _recursions == 0 _WaitSet == NULL
- DEBUG_ONLY(stringStream ss;)
+#ifdef ASSERT
+ stringStream ss;
+#endif
assert((is_busy() | _recursions) == 0, "freeing in-use monitor: %s, "
"recursions=" INTX_FORMAT, is_busy_to_string(&ss), _recursions);
_succ = NULL;
_EntryList = NULL;
_cxq = NULL;
@@ -299,17 +328,23 @@
public:
void* object() const;
void* object_addr();
void set_object(void* obj);
+ void set_allocation_state(AllocationState s);
+ AllocationState allocation_state() const;
+ bool is_free() const;
+ bool is_old() const;
+ bool is_new() const;
// Returns true if the specified thread owns the ObjectMonitor. Otherwise
// returns false and throws IllegalMonitorStateException (IMSE).
bool check_owner(Thread* THREAD);
void clear();
+ void clear_common();
- void enter(TRAPS);
+ bool enter(TRAPS);
void exit(bool not_suspended, TRAPS);
void wait(jlong millis, bool interruptable, TRAPS);
void notify(TRAPS);
void notifyAll(TRAPS);
@@ -319,23 +354,35 @@
#endif
void print_on(outputStream* st) const;
// Use the following at your own risk
intx complete_exit(TRAPS);
- void reenter(intx recursions, TRAPS);
+ bool reenter(intx recursions, TRAPS);
private:
void AddWaiter(ObjectWaiter* waiter);
void INotify(Thread* self);
ObjectWaiter* DequeueWaiter();
void DequeueSpecificWaiter(ObjectWaiter* waiter);
void EnterI(TRAPS);
void ReenterI(Thread* self, ObjectWaiter* self_node);
void UnlinkAfterAcquire(Thread* self, ObjectWaiter* self_node);
int TryLock(Thread* self);
- int NotRunnable(Thread* self, Thread * Owner);
+ int NotRunnable(Thread* self, Thread* Owner);
int TrySpin(Thread* self);
void ExitEpilog(Thread* self, ObjectWaiter* Wakee);
bool ExitSuspendEquivalent(JavaThread* self);
+ void install_displaced_markword_in_object(const oop obj);
};
+// Macro to use guarantee() for more strict AsyncDeflateIdleMonitors
+// checks and assert() otherwise.
+#define ADIM_guarantee(p, ...) \
+ do { \
+ if (AsyncDeflateIdleMonitors) { \
+ guarantee(p, __VA_ARGS__); \
+ } else { \
+ assert(p, __VA_ARGS__); \
+ } \
+ } while (0)
+
#endif // SHARE_RUNTIME_OBJECTMONITOR_HPP
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