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comparison src/os/linux/vm/os_linux.cpp @ 1117:95e9083cf4a7

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6822370: ReentrantReadWriteLock: threads hung when there are no threads holding onto the lock (Netra x4450) Summary: This day one bug is caused by missing memory barriers in various Parker::park() paths that can result in lost wakeups and hangs. Reviewed-by: dice, acorn
author dholmes
date Tue, 01 Dec 2009 22:29:02 -0500
parents 354d3184f6b2
children 167c2986d91b
comparison
equal deleted inserted replaced
1115:4b966d9946a3 1117:95e9083cf4a7
4681 void Parker::park(bool isAbsolute, jlong time) { 4681 void Parker::park(bool isAbsolute, jlong time) {
4682 // Optional fast-path check: 4682 // Optional fast-path check:
4683 // Return immediately if a permit is available. 4683 // Return immediately if a permit is available.
4684 if (_counter > 0) { 4684 if (_counter > 0) {
4685 _counter = 0 ; 4685 _counter = 0 ;
4686 OrderAccess::fence();
4686 return ; 4687 return ;
4687 } 4688 }
4688 4689
4689 Thread* thread = Thread::current(); 4690 Thread* thread = Thread::current();
4690 assert(thread->is_Java_thread(), "Must be JavaThread"); 4691 assert(thread->is_Java_thread(), "Must be JavaThread");
4723 int status ; 4724 int status ;
4724 if (_counter > 0) { // no wait needed 4725 if (_counter > 0) { // no wait needed
4725 _counter = 0; 4726 _counter = 0;
4726 status = pthread_mutex_unlock(_mutex); 4727 status = pthread_mutex_unlock(_mutex);
4727 assert (status == 0, "invariant") ; 4728 assert (status == 0, "invariant") ;
4729 OrderAccess::fence();
4728 return; 4730 return;
4729 } 4731 }
4730 4732
4731 #ifdef ASSERT 4733 #ifdef ASSERT
4732 // Don't catch signals while blocked; let the running threads have the signals. 4734 // Don't catch signals while blocked; let the running threads have the signals.
4763 // If externally suspended while waiting, re-suspend 4765 // If externally suspended while waiting, re-suspend
4764 if (jt->handle_special_suspend_equivalent_condition()) { 4766 if (jt->handle_special_suspend_equivalent_condition()) {
4765 jt->java_suspend_self(); 4767 jt->java_suspend_self();
4766 } 4768 }
4767 4769
4770 OrderAccess::fence();
4768 } 4771 }
4769 4772
4770 void Parker::unpark() { 4773 void Parker::unpark() {
4771 int s, status ; 4774 int s, status ;
4772 status = pthread_mutex_lock(_mutex); 4775 status = pthread_mutex_lock(_mutex);