Re: [PATCH v2 2/2] xen: credit1: avoid boosting vCPUs being "just" migrated

[Dario Faggioli <dario.faggioli@citrix.com>]

[-- Attachment #1.1: Type: text/plain, Size: 1445 bytes --]

On Fri, 2016-02-12 at 02:50 -0700, Jan Beulich wrote:
> > > > On 12.02.16 at 10:37, <dario.faggioli@citrix.com> wrote:
> > @@ -787,6 +788,16 @@ _csched_cpu_pick(const struct scheduler *ops,
> > struct vcpu *vc, bool_t commit)
> >  static int
> >  csched_cpu_pick(const struct scheduler *ops, struct vcpu *vc)
> >  {
> > +    struct csched_vcpu *svc = CSCHED_VCPU(vc);
> > +
> > +    /*
> > +     * We have been called by vcpu_migrate() (in schedule.c), as
> > part
> > +     * of the process of seeing if vc can be migrated to another
> > pcpu.
> > +     * We make a note about this in svc->flags so that later, in
> > +     * csched_vcpu_wake() (still called from vcpu_migrate()) we
> > won't
> > +     * get boosted, which we don't deserve as we are "only"
> > migrating.
> > +     */
> > +    set_bit(CSCHED_FLAG_VCPU_MIGRATING, &svc->flags);
> >      return _csched_cpu_pick(ops, vc, 1);
> >  }
> 
> I think you either want __set_bit() here or ...
> 
Yes, this is completely serialized by the vcpu's scheduler lock, so I
indeed want __set_bit(), sorry for the overlook.

Thanks and Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)


[-- Attachment #1.2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel