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SubjectRe: [PATCH v2 1/1] cgroup: make per-cgroup pressure stall tracking configurable
On Tue, May 18, 2021 at 11:55 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> On Tue, May 18, 2021 at 11:52 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Mon, May 17, 2021 at 07:02:00PM -0700, Suren Baghdasaryan wrote:
> >
> > > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> > > index cc25a3cff41f..4b8e72640ac9 100644
> > > --- a/kernel/sched/psi.c
> > > +++ b/kernel/sched/psi.c
> > > @@ -148,6 +148,7 @@
> > > static int psi_bug __read_mostly;
> > >
> > > DEFINE_STATIC_KEY_FALSE(psi_disabled);
> > > +DEFINE_STATIC_KEY_FALSE(psi_cgroups_disabled);
> >
> > I'm thinking the whole thing will be easier/clearer when you make this:
> >
> > DEFINE_STATIC_KEY_TRUE(psi_cgroups_enabled);
> >
>
> Sounds good. Will respin another version. Thanks for reviewing!

v3 is posted at https://lore.kernel.org/patchwork/patch/1435705

>
>
> > >
> > > #ifdef CONFIG_PSI_DEFAULT_DISABLED
> > > static bool psi_enable;
> > > @@ -211,6 +212,9 @@ void __init psi_init(void)
> > > return;
> > > }
> > >
> > > + if (!cgroup_psi_enabled())
> > > + static_branch_enable(&psi_cgroups_disabled);
> >
> > if (!cgroup_psi_enabled())
> > static_branch_disable(&psi_cgroups_enabled);
> >
> > > +
> > > psi_period = jiffies_to_nsecs(PSI_FREQ);
> > > group_init(&psi_system);
> > > }
> > > @@ -744,23 +748,23 @@ static void psi_group_change(struct psi_group *group, int cpu,
> > >
> > > static struct psi_group *iterate_groups(struct task_struct *task, void **iter)
> > > {
> > > + if (*iter == &psi_system)
> > > + return NULL;
> > > +
> > > #ifdef CONFIG_CGROUPS
> > > + if (!static_branch_likely(&psi_cgroups_disabled)) {
> >
> > if (static_branch_likely(&psi_cgroups_enabled)) {
> >
> > > + struct cgroup *cgroup = NULL;
> > >
> > > + if (!*iter)
> > > + cgroup = task->cgroups->dfl_cgrp;
> > > + else
> > > + cgroup = cgroup_parent(*iter);
> > >
> > > + if (cgroup && cgroup_parent(cgroup)) {
> > > + *iter = cgroup;
> > > + return cgroup_psi(cgroup);
> > > + }
> > > }
> > > #endif
> > > *iter = &psi_system;
> > > return &psi_system;
> >
> > But yes, very nice.
> >
> > --
> > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com.
> >

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