Messages in this thread | | | Date | Fri, 6 Jul 2018 14:12:24 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC] Make need_resched() return true when rcu_urgent_qs requested |
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On Fri, Jul 06, 2018 at 06:14:44PM +0100, David Woodhouse wrote: > On Fri, 2018-07-06 at 10:11 -0700, Paul E. McKenney wrote: > > > The preempt state is alread a bit complicated and shadowed in the > > > preempt_count (on some architectures) adding additional bits to it like > > > this is just asking for trouble. > > > > How about a separate need_resched_rcu() that includes the extra cache > > miss? Or open-coding the rcu_urgent_qs_requested()? > > Peter said "touch two cachelines". He didn't say it was a cache miss.
"... that includes the extra cache touch", then.
> Given that every single cond_resched() call touches the same cache > line, and every single rcu_all_qs() and similar will also touch it, > it's fairly much guaranteed *not* to be a miss... > > ... which is why I didn't really understand why he cared.
Let's see what he says. ;-)
Thanx, Paul
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