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Date: Thu, 2 Apr 2015 15:34:03 +0200 From: Peter Zijlstra <peterz@...radead.org> To: Viresh Kumar <viresh.kumar@...aro.org> Cc: Ingo Molnar <mingo@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, linaro-kernel@...ts.linaro.org, linux-kernel@...r.kernel.org, Kevin Hilman <khilman@...aro.org>, Daniel Lezcano <daniel.lezcano@...aro.org>, Preeti U Murthy <preeti@...ux.vnet.ibm.com>, Frederic Weisbecker <fweisbec@...il.com> Subject: Re: [PATCH 2/3] clockevents: Restart clockevent device before using it again On Fri, Mar 27, 2015 at 10:44:28PM +0530, Viresh Kumar wrote: > Only hrtimer_reprogram() is responsible for programming the clockevent device > for next event, if the clockevent device is stopped earlier. And updating that > alone is sufficient here. > +++ b/kernel/time/hrtimer.c > @@ -566,6 +566,7 @@ static int hrtimer_reprogram(struct hrtimer *timer, > { > struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases); > ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset); > + struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); > int res; > > WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0); > @@ -610,6 +611,10 @@ static int hrtimer_reprogram(struct hrtimer *timer, > if (cpu_base->hang_detected) > return 0; > > + /* Switchback to ONESHOT state */ > + if (unlikely(dev->state == CLOCK_EVT_STATE_ONESHOT_STOPPED)) > + clockevents_set_state(dev, CLOCK_EVT_STATE_ONESHOT); > + > /* > * Clockevents returns -ETIME, when the event was in the past. > */ Should we not do this in tick_program_event() instead? Note that there are a few more places that call that, the two in the hrtimer_interrupt() should be safe because if we're handling the interrupt its cannot be stopped anyhow. hrtimer_force_reprogram() seems to need the annotation regardless. Furthermore, by putting it in tick_program_event() you also don't need to fixup tick_nohz_restart(). Or am I completely missing something? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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