src/os/aix/vm/os_aix.cpp
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webrev Cdiff src/os/aix/vm/os_aix.cpp
src/os/aix/vm/os_aix.cpp
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*** 2655,2669 ****
void os::hint_no_preempt() {}
////////////////////////////////////////////////////////////////////////////////
// suspend/resume support
! // the low-level signal-based suspend/resume support is a remnant from the
// old VM-suspension that used to be for java-suspension, safepoints etc,
! // within hotspot. Now there is a single use-case for this:
! // - calling get_thread_pc() on the VMThread by the flat-profiler task
! // that runs in the watcher thread.
// The remaining code is greatly simplified from the more general suspension
// code that used to be used.
//
// The protocol is quite simple:
// - suspend:
--- 2655,2668 ----
void os::hint_no_preempt() {}
////////////////////////////////////////////////////////////////////////////////
// suspend/resume support
! // The low-level signal-based suspend/resume support is a remnant from the
// old VM-suspension that used to be for java-suspension, safepoints etc,
! // within hotspot. Currently used by JFR's OSThreadSampler
! //
// The remaining code is greatly simplified from the more general suspension
// code that used to be used.
//
// The protocol is quite simple:
// - suspend:
*** 2675,2685 ****
--- 2674,2690 ----
// - sets target osthread state to continue
// - sends signal to end the sigsuspend loop in the SR_handler
//
// Note that the SR_lock plays no role in this suspend/resume protocol,
// but is checked for NULL in SR_handler as a thread termination indicator.
+ // The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
//
+ // Note that resume_clear_context() and suspend_save_context() are needed
+ // by SR_handler(), so that fetch_frame_from_ucontext() works,
+ // which in part is used by:
+ // - Forte Analyzer: AsyncGetCallTrace()
+ // - StackBanging: get_frame_at_stack_banging_point()
static void resume_clear_context(OSThread *osthread) {
osthread->set_ucontext(NULL);
osthread->set_siginfo(NULL);
}
*** 3682,3729 ****
do_task(context);
do_resume(_thread->osthread());
}
}
- class PcFetcher : public os::SuspendedThreadTask {
- public:
- PcFetcher(Thread* thread) : os::SuspendedThreadTask(thread) {}
- ExtendedPC result();
- protected:
- void do_task(const os::SuspendedThreadTaskContext& context);
- private:
- ExtendedPC _epc;
- };
-
- ExtendedPC PcFetcher::result() {
- guarantee(is_done(), "task is not done yet.");
- return _epc;
- }
-
- void PcFetcher::do_task(const os::SuspendedThreadTaskContext& context) {
- Thread* thread = context.thread();
- OSThread* osthread = thread->osthread();
- if (osthread->ucontext() != NULL) {
- _epc = os::Aix::ucontext_get_pc((const ucontext_t *) context.ucontext());
- } else {
- // NULL context is unexpected, double-check this is the VMThread.
- guarantee(thread->is_VM_thread(), "can only be called for VMThread");
- }
- }
-
- // Suspends the target using the signal mechanism and then grabs the PC before
- // resuming the target. Used by the flat-profiler only
- ExtendedPC os::get_thread_pc(Thread* thread) {
- // Make sure that it is called by the watcher for the VMThread.
- assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
- assert(thread->is_VM_thread(), "Can only be called for VMThread");
-
- PcFetcher fetcher(thread);
- fetcher.run();
- return fetcher.result();
- }
-
////////////////////////////////////////////////////////////////////////////////
// debug support
bool os::find(address addr, outputStream* st) {
--- 3687,3696 ----
src/os/aix/vm/os_aix.cpp
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