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// have busy multi-threaded access. _header and _object are set at initial
// inflation. The _object does not change, so it is a good choice to share
// its cache line with _header.
DEFINE_PAD_MINUS_SIZE(0, OM_CACHE_LINE_SIZE, sizeof(volatile markWord) +
sizeof(WeakHandle));
- // Used by async deflation as a marker in the _owner field:
- #define DEFLATER_MARKER reinterpret_cast<void*>(-1)
+ // Used by async deflation as a marker in the _owner field.
+ // Note that the choice of the two markers is peculiar:
+ // - They need to represent values that cannot be pointers. In particular,
+ // we achieve this by using the lowest two bits
+ // - ANONYMOUS_OWNER should be a small value, it is used in generated code
+ // and small values encode much better
+ // - We test for anonymous owner by testing for the lowest bit, therefore
+ // DEFLATER_MARKER must *not* have that bit set.
+ #define DEFLATER_MARKER reinterpret_cast<void*>(2)
+ #define ANONYMOUS_OWNER reinterpret_cast<void*>(1)
void* volatile _owner; // pointer to owning thread OR BasicLock
volatile uint64_t _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
static int Knob_SpinLimit;
// TODO-FIXME: the "offset" routines should return a type of off_t instead of int ...
// ByteSize would also be an appropriate type.
+ static int header_offset_in_bytes() { return offset_of(ObjectMonitor, _header); }
static int owner_offset_in_bytes() { return offset_of(ObjectMonitor, _owner); }
static int recursions_offset_in_bytes() { return offset_of(ObjectMonitor, _recursions); }
static int cxq_offset_in_bytes() { return offset_of(ObjectMonitor, _cxq); }
static int succ_offset_in_bytes() { return offset_of(ObjectMonitor, _succ); }
static int EntryList_offset_in_bytes() { return offset_of(ObjectMonitor, _EntryList); }
// 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.
void* try_set_owner_from(void* old_value, void* new_value);
+ void set_owner_anonymous() {
+ set_owner_from(NULL, ANONYMOUS_OWNER);
+ }
+
+ bool is_owner_anonymous() const {
+ return owner_raw() == ANONYMOUS_OWNER;
+ }
+
+ void set_owner_from_anonymous(Thread* owner) {
+ set_owner_from(ANONYMOUS_OWNER, owner);
+ }
+
// Simply get _next_om field.
ObjectMonitor* next_om() const;
// Simply set _next_om field to new_value.
void set_next_om(ObjectMonitor* new_value);
// Use the following at your own risk
intx complete_exit(JavaThread* current);
bool reenter(intx recursions, JavaThread* current);
+ static void maybe_deflate_dead(oop* p);
+
private:
void AddWaiter(ObjectWaiter* waiter);
void INotify(JavaThread* current);
ObjectWaiter* DequeueWaiter();
void DequeueSpecificWaiter(ObjectWaiter* waiter);
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