Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Thu, 24 Nov 2016 14:44:04 +0100 | Subject | Re: [PATCH v3 1/3] idle: add support for tasks that inject idle |
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On Thu, Nov 24, 2016 at 12:04 PM, Ingo Molnar <mingo@kernel.org> wrote: > > * Peter Zijlstra <peterz@infradead.org> wrote: > >> On Wed, Nov 23, 2016 at 12:13:08PM -0800, Jacob Pan wrote: >> > @@ -280,6 +272,58 @@ bool cpu_in_idle(unsigned long pc) >> > pc < (unsigned long)__cpuidle_text_end; >> > } >> > >> > +static enum hrtimer_restart idle_inject_timer_fn(struct hrtimer *hrtimer) >> > +{ >> > + set_tsk_need_resched(current); >> > + return HRTIMER_NORESTART; >> > +} >> > + >> > +void play_idle(unsigned long duration_ms) >> > +{ >> > + struct hrtimer timer; >> > + unsigned long end_time; >> > + >> > + /* >> > + * Only FIFO tasks can disable the tick since they don't need the forced >> > + * preemption. >> > + */ >> > + WARN_ON_ONCE(current->policy != SCHED_FIFO); >> > + WARN_ON_ONCE(current->nr_cpus_allowed != 1); >> > + WARN_ON_ONCE(!(current->flags & PF_KTHREAD)); >> > + WARN_ON_ONCE(!(current->flags & PF_NO_SETAFFINITY)); >> > + >> > + rcu_sleep_check(); >> > + preempt_disable(); >> > + current->flags |= PF_IDLE; >> > + cpuidle_use_deepest_state(true); >> > + >> > + /* >> > + * If duration is 0, we will return after a natural wake event occurs. If >> > + * duration is none zero, we will go back to sleep if we were woken up earlier. >> > + * We also set up a timer to make sure we don't oversleep in deep idle. >> > + */ >> > + if (!duration_ms) >> > + do_idle(); >> >> OK, so that doesn't make any sense, you should not be calling this >> without a timeout. >> >> > + else { >> > + hrtimer_init_on_stack(&timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); >> > + timer.function = idle_inject_timer_fn; >> > + hrtimer_start(&timer, ms_to_ktime(duration_ms), >> > + HRTIMER_MODE_REL_PINNED); >> > + end_time = jiffies + msecs_to_jiffies(duration_ms); >> > + >> > + while (time_after(end_time, jiffies)) >> > + do_idle(); >> > + } >> > + hrtimer_cancel(&timer); >> > + >> > + cpuidle_use_deepest_state(false); >> > + current->flags &= ~PF_IDLE; >> > + >> > + preempt_fold_need_resched(); >> > + preempt_enable(); >> > +} >> > +EXPORT_SYMBOL_GPL(play_idle); >> >> >> How about something like so... (since I had to edit, I fixed up most >> things Ingo complained about as well). >> >> Note that it doesn't build because of a distinct lack of >> cpuidle_use_deepest_state() in my kernel tree. > > Ok, I really like this one, it so much cleaner! > > If the patch builds & works: > > Acked-by: Ingo Molnar <mingo@kernel.org>
OK, thanks!
Jacob, can you please test this one along with the rest of the series?
Thanks, Rafael
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