Re: [PATCH,RFC] perf: panic due to inclied cpu context task_ctxvalue

From: Peter Zijlstra
Date: Wed Mar 30 2011 - 11:58:14 EST


On Wed, 2011-03-30 at 17:52 +0200, Oleg Nesterov wrote:
> On 03/30, Peter Zijlstra wrote:
> >
> > On Wed, 2011-03-30 at 17:32 +0200, Oleg Nesterov wrote:
> > > > +#ifdef HAVE_JUMP_LABEL
> > > > +static inline
> > > > +void perf_sched_events_inc(void)
> > > > +{
> > > > + jump_label_inc(&perf_sched_events_out);
> > > > + smp_mb__after_atomic_inc();
> > > > + jump_label_inc(&perf_sched_events_in);
> > > > +}
> > >
> > > probably smp_mb__after_atomic_inc() needs a comment...
> >
> > You don't need it, jump_label_inc() uses atomic_add_return() which
> > implies a full mb.
>
> Yes, but only if HAVE_JUMP_LABEL.

argh, indeed.
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