Messages in this thread | | | Subject | Re: [PATCH] psi: get poll_work to run when calling poll syscall next time | From | Jason Xing <> | Date | Mon, 29 Jul 2019 16:12:44 +0800 |
| |
Hello,
Could someone take a quick look at this patch? It's not complicated at all, just one line added into PSI which can make the poll() run in the right way.
Thanks, Jason
On 2019/7/23 下午2:45, 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> > --- > 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); > } >
| |