2729 }
2730
2731 // Handler function invoked when a thread's execution is suspended or
2732 // resumed. We have to be careful that only async-safe functions are
2733 // called here (Note: most pthread functions are not async safe and
2734 // should be avoided.)
2735 //
2736 // Note: sigwait() is a more natural fit than sigsuspend() from an
2737 // interface point of view, but sigwait() prevents the signal hander
2738 // from being run. libpthread would get very confused by not having
2739 // its signal handlers run and prevents sigwait()'s use with the
2740 // mutex granting granting signal.
2741 //
2742 // Currently only ever called on the VMThread or JavaThread
2743 //
2744 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2745 // Save and restore errno to avoid confusing native code with EINTR
2746 // after sigsuspend.
2747 int old_errno = errno;
2748
2749 Thread* thread = Thread::current();
2750 OSThread* osthread = thread->osthread();
2751 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2752
2753 os::SuspendResume::State current = osthread->sr.state();
2754 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2755 suspend_save_context(osthread, siginfo, context);
2756
2757 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2758 os::SuspendResume::State state = osthread->sr.suspended();
2759 if (state == os::SuspendResume::SR_SUSPENDED) {
2760 sigset_t suspend_set; // signals for sigsuspend()
2761
2762 // get current set of blocked signals and unblock resume signal
2763 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2764 sigdelset(&suspend_set, SR_signum);
2765
2766 sr_semaphore.signal();
2767 // wait here until we are resumed
2768 while (1) {
2769 sigsuspend(&suspend_set);
2770
2771 os::SuspendResume::State result = osthread->sr.running();
|
2729 }
2730
2731 // Handler function invoked when a thread's execution is suspended or
2732 // resumed. We have to be careful that only async-safe functions are
2733 // called here (Note: most pthread functions are not async safe and
2734 // should be avoided.)
2735 //
2736 // Note: sigwait() is a more natural fit than sigsuspend() from an
2737 // interface point of view, but sigwait() prevents the signal hander
2738 // from being run. libpthread would get very confused by not having
2739 // its signal handlers run and prevents sigwait()'s use with the
2740 // mutex granting granting signal.
2741 //
2742 // Currently only ever called on the VMThread or JavaThread
2743 //
2744 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
2745 // Save and restore errno to avoid confusing native code with EINTR
2746 // after sigsuspend.
2747 int old_errno = errno;
2748
2749 Thread* thread = Thread::current_or_null_safe();
2750 assert(thread != NULL, "Missing current thread in SR_handler");
2751
2752 // On some systems we have seen signal delivery get "stuck" until the signal
2753 // mask is changed as part of thread termination. Check the current thread
2754 // has not already terminated (via SR_lock()) - else the following assertion
2755 // will fail because the thread is no longer a JavaThread as the ~JavaThread
2756 // destructor has completed.
2757
2758 if (thread->SR_lock() == NULL)
2759 return;
2760
2761 assert(thread->is_VM_thread() || thread->is_Java_thread(), "Must be VMThread or JavaThread");
2762
2763 OSThread* osthread = thread->osthread();
2764
2765 os::SuspendResume::State current = osthread->sr.state();
2766 if (current == os::SuspendResume::SR_SUSPEND_REQUEST) {
2767 suspend_save_context(osthread, siginfo, context);
2768
2769 // attempt to switch the state, we assume we had a SUSPEND_REQUEST
2770 os::SuspendResume::State state = osthread->sr.suspended();
2771 if (state == os::SuspendResume::SR_SUSPENDED) {
2772 sigset_t suspend_set; // signals for sigsuspend()
2773
2774 // get current set of blocked signals and unblock resume signal
2775 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
2776 sigdelset(&suspend_set, SR_signum);
2777
2778 sr_semaphore.signal();
2779 // wait here until we are resumed
2780 while (1) {
2781 sigsuspend(&suspend_set);
2782
2783 os::SuspendResume::State result = osthread->sr.running();
|