Re: [Xen-devel] [PATCH] xen/sched: fix a potential issue with core scheduling

[Jürgen Groß <jgross@xxxxxxxx>]

On 12.11.19 10:14, Dario Faggioli wrote:
> On Fri, 2019-11-08 at 07:57 +0100, Juergen Gross wrote:
> > cpupool_online_cpumask() is used by credit and rt scheduler. It
> > returns
> > all the cpus of a cpupool or all online cpus in case no cpupool is
> > specified.
> >
> > The "no cpupool" case can be dropped, as no scheduler other than the
> > init scheduler will ever work on cpus not associated with any
> > cpupool.
> Yes, this is a cool thing about having the init cpupool/idle scheduler
> in place. It's even cooler in Credit2, where it will allow us to drop
> some of the cpumask_and() cpumask_or() operations.
>
> It's the reason why, even before core scheduling, I was considering
> doing an idle scheduler myself.
>
> I'll get to write that patch (the one for Credit2, I mean) at some
> point. :-)
>
> > As the individual schedulers should only ever work on scheduling
> > resources instead of individual cpus, their cpupool_online_cpumask()
> > use should be replaced by cpupool->res_valid.
> >
> > Note that only with core scheduling active this might result in
> > potential problems, as with cpu scheduling both masks are identical.
> >
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> Reviewed-by: Dario Faggioli <dfaggioli@xxxxxxxx>
And with my release manager hat on:

Release-acked-by: Juergen Gross <jgross@xxxxxxxx>


Juergen

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel