Re: [PATCH 22/38] tick-sched: no need to recheck cpu_online() in can_stop_idle_tick()

From: Stephen Boyd
Date: Mon Apr 14 2014 - 15:52:21 EST


On 04/14/14 09:23, Viresh Kumar wrote:
> We have already checked if 'cpu' is online or not and so don't need to recheck
> it.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>

Hm... doing some git archeology shows fa116ea35ec7 (nohz: no softirq
pending warnings for offline cpus, 2008-12-11), where the cpu_online()
check was added. Before that commit we already checked cpu_online()
similar to how the code is today. Perhaps we need to add a comment here?

> ---
> kernel/time/tick-sched.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 9cbba513..c81b6cf 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -716,7 +716,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
> if (need_resched())
> return false;
>
> - if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
> + if (unlikely(local_softirq_pending())) {
> static int ratelimit;
>
> if (ratelimit < 10 &&


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