lkml.org 
[lkml]   [2016]   [Sep]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 5/8] sched,x86: Enable Turbo Boost Max Technology
From
Date
On Thu, 2016-09-08 at 20:22 +0200, Peter Zijlstra wrote:
> On Thu, Sep 08, 2016 at 11:09:28AM -0700, Tim Chen wrote:
> >
> > On Thu, Sep 08, 2016 at 09:59:55AM +0200, Peter Zijlstra wrote:
> > >
> > > I think there's a race here, if two tasks were to write to the
> > > sysctl
> > > they'd both change the value before getting stuck on the mutex in
> > > enable_sched_itmt().
> > >
> > > One way around that is doing something like:
> > >
> > >
> > > struct ctl_table t;
> > > int val = sysctl_sched_itmt_enabled;
> > >
> > > t = *table;
> > > t.data = &val;
> > >
> > > proc_dointvec_minmax(&t, ...);
> > >
> > > /* and update the sysctl_sched_itmt_enabled value inside the
> > > mutex */
> > > enable_sched_itmi(val);
> >
> > Peter,
> >
> > Since enable_sched_itmt is only used by sched_itmt_update_handler,
> > I've moved the mutex locking to sched_itmt_update_handler to
> > eliminate
> > the race condition in the code path you mentioned.
>
> That is indeed simpler. Thanks!
Do we need to send v3 to include these changes?

Thanks,
Srinivas

> --
> To unsubscribe from this list: send the line "unsubscribe linux-pm"
> in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

\
 
 \ /
  Last update: 2016-09-17 09:58    [W:0.092 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site