Messages in this thread Patch in this message | | | From | Jason Xing <> | Subject | [PATCH] psi: get poll_work to run when calling poll syscall next time | Date | Tue, 23 Jul 2019 14:45:39 +0800 |
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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); } -- 1.8.3.1
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