Messages in this thread | | | Date | Wed, 21 Oct 2020 12:12:57 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 1/1] sched: watchdog: Touch kernel watchdog with sched count |
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On Tue, Oct 20, 2020 at 01:57:04PM -0700, Xi Wang wrote:
> + if (watchdog_touch_with_sched) { > + /* Trigger reschedule for the next round */ > + set_tsk_need_resched(current); > + set_preempt_need_resched();
Blergh.. that's gross. This relies on this being in IRQ context and either: PREEMPT=y *OR* this always being from userspace. Otherwise there's no guarantee the return-from-interrupt will actually schedule.
> + /* sched_count increase in __schedule is taken as watchdog touched */ > + if (sched_get_count(smp_processor_id()) - > + __this_cpu_read(watchdog_sched_prev)) { > + __touch_watchdog(); > + __this_cpu_write(soft_watchdog_warn, false); > + return HRTIMER_RESTART; > + } > + } > + > /* check for a softlockup > * This is done by making sure a high priority task is > * being scheduled. The task touches the watchdog to > -- > 2.29.0.rc1.297.gfa9743e501-goog >
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