Re: [RFC][PATCH] sched: might_sleep(): do rate-limiting before sanity checks

From: Peter Zijlstra
Date: Thu Jun 25 2015 - 03:43:51 EST


On Wed, Jun 24, 2015 at 08:36:38PM -0700, Dave Hansen wrote:
> On 06/24/2015 05:03 PM, Dave Hansen wrote:
> > In any case, we ratelimit might_sleep() checks anyway. But, we
> > do the ratelimiting *after* we check the other conditions for
> > might_sleep() including the (costly) irqs_disabled() call.
>
> Thinking about this a bit more, this patch is wrong.
>
> This only does a _check_ once per jiffy instead of just one warning per
> jiffy, which is totally bogus.
>
> I would be interested, though, if anybody has any ideas about speeding
> up the irqs_disabled() checking.

Thomas has something up his sleeve..
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