Messages in this thread | | | Date | Tue, 20 Dec 2022 22:18:02 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC/RFT PATCH 1/2] sched/core: Check and schedule ksoftirq |
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On Tue, Dec 20, 2022 at 09:51:09PM +0100, Peter Zijlstra wrote: > On Mon, Dec 19, 2022 at 02:54:55PM -0800, srinivas pandruvada wrote: > > > But after ksoftirqd_run_end(), which will renable local irq, this may > > further cause more soft irq pending. Here RCU soft irq entry continues > > Right you are.. what about if we spell the idle.c thing like so instead? > > Then we repeat the softirq thing every time we drop out of the idle loop > for a reschedule.
Uff, that obviously can't work because we already have preemption disabled here, this needs a bit more work. I think it's possible to re-arrange things a bit.
I'll try and have a look tomorrow, but the kids have their xmas play at school so who knows what I'll get done.
> diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index f26ab2675f7d..6dce49813bcc 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -381,8 +381,13 @@ void play_idle_precise(u64 duration_ns, u64 latency_ns) > hrtimer_start(&it.timer, ns_to_ktime(duration_ns), > HRTIMER_MODE_REL_PINNED_HARD); > > - while (!READ_ONCE(it.done)) > + while (!READ_ONCE(it.done)) { > + rt_mutex_lock(&per_cpu(ksoftirq_lock, cpu)); > + __run_ksoftirqd(smp_processor_id()); > + rt_mutex_unlock(&per_cpu(ksoftirq_lock, cpu)); > + > do_idle(); > + } > > cpuidle_use_deepest_state(0); > current->flags &= ~PF_IDLE;
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