< prev index next >
src/hotspot/share/runtime/objectMonitor.hpp
Print this page
rev 58110 : v2.09a with 8235795, 8235931 and 8236035 extracted; rebased to jdk-14+28; merge with 8236035.patch.cr1; merge with 8235795.patch.cr1; merge with 8236035.patch.cr2; merge with 8235795.patch.cr2; merge with 8235795.patch.cr3.
rev 58111 : See CR9-to-CR10-changes; merge with jdk-15+11.
*** 125,158 ****
// the current build platform.
#define OM_CACHE_LINE_SIZE DEFAULT_CACHE_LINE_SIZE
#endif
class ObjectMonitor {
friend class ObjectSynchronizer;
friend class ObjectWaiter;
friend class VMStructs;
JVMCI_ONLY(friend class JVMCIVMStructs;)
// 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:
// 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));
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
// cache line with _owner.
DEFINE_PAD_MINUS_SIZE(1, OM_CACHE_LINE_SIZE, sizeof(void* volatile) +
sizeof(volatile jlong));
ObjectMonitor* _next_om; // Next ObjectMonitor* linkage
volatile intx _recursions; // recursion count, 0 for first entry
ObjectWaiter* volatile _EntryList; // Threads blocked on entry or reentry.
// The list is actually composed of WaitNodes,
// acting as proxies for Threads.
--- 125,172 ----
// the current build platform.
#define OM_CACHE_LINE_SIZE DEFAULT_CACHE_LINE_SIZE
#endif
class ObjectMonitor {
+ friend class ObjectMonitorHandle;
friend class ObjectSynchronizer;
friend class ObjectWaiter;
friend class VMStructs;
JVMCI_ONLY(friend class JVMCIVMStructs;)
// 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
! 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, _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 _ref_count 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
// cache line with _owner.
DEFINE_PAD_MINUS_SIZE(1, OM_CACHE_LINE_SIZE, sizeof(void* volatile) +
sizeof(volatile jlong));
+ jint _ref_count; // ref count for ObjectMonitor* and used by the async deflation
+ // protocol. See ObjectSynchronizer::deflate_monitor_using_JT().
+ // Separate _ref_count and _next_om on different cache lines since
+ // both can have busy multi-threaded access.
+ DEFINE_PAD_MINUS_SIZE(2, OM_CACHE_LINE_SIZE, sizeof(volatile jint));
ObjectMonitor* _next_om; // Next ObjectMonitor* linkage
volatile intx _recursions; // recursion count, 0 for first entry
ObjectWaiter* volatile _EntryList; // Threads blocked on entry or reentry.
// The list is actually composed of WaitNodes,
// acting as proxies for Threads.
*** 164,174 ****
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()
// along with other fields to determine if an ObjectMonitor can be
! // deflated. See ObjectSynchronizer::deflate_monitor().
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
--- 178,189 ----
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()
// along with other fields to determine if an ObjectMonitor can be
! // deflated. See ObjectSynchronizer::deflate_monitor() and
! // ObjectSynchronizer::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
*** 231,251 ****
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);
}
const char* is_busy_to_string(stringStream* ss);
intptr_t is_entered(Thread* current) const;
! void* owner() const;
// 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 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.
--- 246,282 ----
volatile markWord* header_addr();
void set_header(markWord hdr);
intptr_t is_busy() const {
// TODO-FIXME: assert _owner == null implies _recursions = 0
! // We do not include _ref_count in the is_busy() check because
! // _ref_count is for indicating that the ObjectMonitor* is in
! // use which is orthogonal to whether the ObjectMonitor itself
! // is in use for a locking operation.
! intptr_t ret_code = _contentions | _waiters | intptr_t(_cxq) | intptr_t(_EntryList);
! if (!AsyncDeflateIdleMonitors) {
! ret_code |= intptr_t(_owner);
! } else {
! 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; // Returns NULL if DEFLATER_MARKER is observed.
! // Returns true if owner field == DEFLATER_MARKER and false otherwise.
! bool owner_is_DEFLATER_MARKER();
// 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.
*** 284,294 ****
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;)
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;
--- 315,327 ----
void Recycle() {
// TODO: add stronger asserts ...
// _cxq == 0 _succ == NULL _owner == NULL _waiters == 0
// _contentions == 0 EntryList == NULL
// _recursions == 0 _WaitSet == NULL
! #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;
*** 299,313 ****
--- 332,355 ----
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;
+ void dec_ref_count();
+ void inc_ref_count();
+ jint ref_count() 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_using_JT();
void enter(TRAPS);
void exit(bool not_suspended, TRAPS);
void wait(jlong millis, bool interruptable, TRAPS);
void notify(TRAPS);
*** 330,341 ****
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 TrySpin(Thread* self);
void ExitEpilog(Thread* self, ObjectWaiter* Wakee);
bool ExitSuspendEquivalent(JavaThread* self);
};
#endif // SHARE_RUNTIME_OBJECTMONITOR_HPP
--- 372,417 ----
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 TrySpin(Thread* self);
void ExitEpilog(Thread* self, ObjectWaiter* Wakee);
bool ExitSuspendEquivalent(JavaThread* self);
+ void install_displaced_markword_in_object(const oop obj);
};
+ // A helper object for managing an ObjectMonitor*'s ref_count. There
+ // are special safety considerations when async deflation is used.
+ class ObjectMonitorHandle : public StackObj {
+ private:
+ ObjectMonitor* _om_ptr;
+ public:
+ ObjectMonitorHandle() { _om_ptr = NULL; }
+ ~ObjectMonitorHandle();
+
+ ObjectMonitor* om_ptr() const { return _om_ptr; }
+ // Save the ObjectMonitor* associated with the specified markWord and
+ // increment the ref_count.
+ bool save_om_ptr(oop object, markWord mark);
+ // Save the specified ObjectMonitor* if safe and increment the ref_count.
+ bool save_om_ptr_if_safe(ObjectMonitor* om_ptr);
+ // Unset the _om_ptr field and decrement the ref_count.
+ void unset_om_ptr();
+
+ // For internal use by ObjectSynchronizer::inflate().
+ void set_om_ptr(ObjectMonitor* om_ptr);
+ };
+
+ // 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
< prev index next >