Messages in this thread | | | Date | Tue, 23 Jul 2019 18:02:09 +0800 | From | Caspar Zhang <> | Subject | Re: [PATCH] psi: get poll_work to run when calling poll syscall next time |
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On Tue, Jul 23, 2019 at 02:45:39PM +0800, Jason Xing wrote: > Only when calling the poll syscall the first time can user > receive POLLPRI correctly. After that, user always fails to > acquire the event signal. > > Reproduce case: > 1. Get the monitor code in Documentation/accounting/psi.txt > 2. Run it, and wait for the event triggered. > 3. Kill and restart the process. > > If the user doesn't kill the monitor process, it seems the > poll_work works fine. After killing and restarting the monitor, > the poll_work in kernel will never run again due to the wrong > value of poll_scheduled. Therefore, we should reset the value > as group_init() does after the last trigger is destroyed. > > Signed-off-by: Jason Xing <kerneljasonxing@linux.alibaba.com>
Reviewed-by: Caspar Zhang <caspar@linux.alibaba.com>
> --- > kernel/sched/psi.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c > index 7acc632..66f4385 100644 > --- a/kernel/sched/psi.c > +++ b/kernel/sched/psi.c > @@ -1133,6 +1133,12 @@ static void psi_trigger_destroy(struct kref *ref) > if (kworker_to_destroy) { > kthread_cancel_delayed_work_sync(&group->poll_work); > kthread_destroy_worker(kworker_to_destroy); > + /* > + * The poll_work should have the chance to be put into the > + * kthread queue when calling poll syscall next time. So > + * reset poll_scheduled to zero as group_init() does > + */ > + atomic_set(&group->poll_scheduled, 0); > } > kfree(t); > } > -- > 1.8.3.1 >
-- Thanks, Caspar
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