void Parker::park(bool isAbsolute, jlong time) {
// Optional fast-path check:
// Return immediately if a permit is available.
if (_counter > 0) {
_counter = 0 ;
OrderAccess::fence();
return ;
}
Thread* thread = Thread::current();
assert(thread->is_Java_thread(), "Must be JavaThread");
JavaThread *jt = (JavaThread *)thread;
// Optional optimization -- avoid state transitions if there"s an interrupt pending.
// Check interrupt before trying to wait
if (Thread::is_interrupted(thread, false)) {
return;
}
// Next, demultiplex/decode time arguments
timespec absTime;
if (time < 0 || (isAbsolute && time == 0) ) { // don"t wait at all
return;
}
if (time > 0) {
unpackTime(&absTime, isAbsolute, time);
}
// Enter safepoint region
// Beware of deadlocks such as 6317397.
// The per-thread Parker:: mutex is a classic leaf-lock.
// In particular a thread must never block on the Threads_lock while
// holding the Parker:: mutex. If safepoints are pending both the
// the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
ThreadBlockInVM tbivm(jt);
// Don"t wait if cannot get lock since interference arises from
// unblocking. Also. check interrupt before trying wait
if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
return;
}
int status ;
if (_counter > 0) { // no wait needed
_counter = 0;
status = pthread_mutex_unlock(_mutex);
assert (status == 0, "invariant") ;
OrderAccess::fence();
return;
}
-sharpifdef ASSERT
// Don"t catch signals while blocked; let the running threads have the signals.
// (This allows a debugger to break into the running thread.)
sigset_t oldsigs;
sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
-sharpendif
OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
jt->set_suspend_equivalent();
// cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
if (time == 0) {
status = pthread_cond_wait (_cond, _mutex) ;
} else {
status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
if (status != 0 && WorkAroundNPTLTimedWaitHang) {
pthread_cond_destroy (_cond) ;
pthread_cond_init (_cond, NULL);
}
}
assert_status(status == 0 || status == EINTR ||
status == ETIME || status == ETIMEDOUT,
status, "cond_timedwait");
-sharpifdef ASSERT
pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
-sharpendif
_counter = 0 ;
status = pthread_mutex_unlock(_mutex) ;
assert_status(status == 0, status, "invariant") ;
// If externally suspended while waiting, re-suspend
if (jt->handle_special_suspend_equivalent_condition()) {
jt->java_suspend_self();
}
OrderAccess::fence();
} the above code is jvm to implement the function of LockSupport.park (),
status = os::Linux::safe_cond_timedwait (_ cond, _ mutex, & absTime);
here::, I don"t quite understand. First of all, I don"t see where the class definition of os is, and secondly, I don"t see the definition of linux in os. Can you let me know if you have seen this source code? -sharp-sharp-sharp problem description
the environmental background of the problems and what methods you have tried
related codes
/ / Please paste the code text below (do not replace the code with pictures)