Re: [PATCH 1/1] cgroup: make per-cgroup pressure stall tracking configurable

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, May 14, 2021 at 4:42 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Thu, May 13, 2021 at 10:53:49AM -0700, Suren Baghdasaryan wrote:
>
> > +bool cgroup_psi_enabled(void)
> > +{
> > +     return (cgroup_feature_disable_mask & (1 << OPT_FEATURE_PRESSURE)) == 0;
> > +}
>
> > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> > index cc25a3cff41f..c73efd7d4fba 100644
> > --- a/kernel/sched/psi.c
> > +++ b/kernel/sched/psi.c
> > @@ -747,9 +747,12 @@ static struct psi_group *iterate_groups(struct task_struct *task, void **iter)
> >  #ifdef CONFIG_CGROUPS
> >       struct cgroup *cgroup = NULL;
> >
> > -     if (!*iter)
> > +     if (!*iter) {
> > +             /* Skip to psi_system if per-cgroup accounting is disabled */
> > +             if (!cgroup_psi_enabled())
> > +                     goto update_sys;
> >               cgroup = task->cgroups->dfl_cgrp;
> > -     else if (*iter == &psi_system)
> > +     } else if (*iter == &psi_system)
> >               return NULL;
> >       else
> >               cgroup = cgroup_parent(*iter);
> > @@ -758,6 +761,7 @@ static struct psi_group *iterate_groups(struct task_struct *task, void **iter)
> >               *iter = cgroup;
> >               return cgroup_psi(cgroup);
> >       }
> > +update_sys:
> >  #else
> >       if (*iter)
> >               return NULL;
>
> I'm confused; shouldn't that do the same as that #else branch?

Correct, for this function CONFIG_CGROUPS=n and
cgroup_disable=pressure are treated the same. True, from the code it's
not very obvious. Do you have some refactoring in mind that would make
it more explicit?

>Also, can you pretty please make cgroup_psi_enabled() a static_key ?

Certainly, will post an update on Monday.
Thanks for the feedback, Peter!

>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@xxxxxxxxxxx.
>



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]

  Powered by Linux