linux-kernel - Re: [PATCH v3 1/4] sched: cgroup SCHED

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 23 Aug 2021 10:29:53 -0700
From:   Josh Don <joshdon@...gle.com>
To:     Tao Zhou <tao.zhou@...ux.dev>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Paul Turner <pjt@...gle.com>,
        Oleg Rombakh <olegrom@...gle.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Steve Sistare <steven.sistare@...cle.com>,
        Tejun Heo <tj@...nel.org>, Rik van Riel <riel@...riel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/4] sched: cgroup SCHED_IDLE support

Hi Tao,

On Fri, Aug 20, 2021 at 1:38 AM Tao Zhou <tao.zhou@...ux.dev> wrote:
[snip]
> >  #ifdef CONFIG_SMP
> >  extern void set_task_rq_fair(struct sched_entity *se,
> >                            struct cfs_rq *prev, struct cfs_rq *next);
> > @@ -601,6 +606,9 @@ struct cfs_rq {
> >       struct list_head        leaf_cfs_rq_list;
> >       struct task_group       *tg;    /* group that "owns" this runqueue */
> >
> > +     /* Locally cached copy of our task_group's idle value */
> > +     int                     idle;
> > +
> >  #ifdef CONFIG_CFS_BANDWIDTH
> >       int                     runtime_enabled;
> >       s64                     runtime_remaining;
> > --
> > 2.33.0.rc2.250.ged5fa647cd-goog
> >
>
> Cfs_rq and tg define @idle with int type.
> In sched_group_set_idle(..., long idle), @idle is long type.
> Use int instead.
>
> But, you filter idle value:
>
>     if (idle < 0 || idle > 1)
>         return -EINVAL;
>
> So, no effect here.. Just @idle can use 4 bytes.
>
>
>
> Thanks,
> Tao

The use of 'long'  there is because the input from the cgroup
interface is a 64 bit value.

- Josh