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From:   Suren Baghdasaryan <surenb@google.com>
Date:   Thu, 19 Oct 2023 09:07:50 -0700
Message-ID: <CAJuCfpHi=jN+8NF1n8-9U2b-Aw7hbt3NHgV=y55y=Wtd0FnRxQ@mail.gmail.com>
Subject: Re: [PATCH linux-next v3 3/4] sched/psi: update rtpoll_next_update
 after update triggers and rtpoll_total
To:     yang.yang29@zte.com.cn
Cc:     mingo@kernel.org, peterz@infradead.org, hannes@cmpxchg.org,
        mingo@redhat.com, linux-kernel@vger.kernel.org,
        juri.lelli@redhat.com
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On Tue, Oct 10, 2023 at 1:43=E2=80=AFAM <yang.yang29@zte.com.cn> wrote:
>
> From: Yang Yang <yang.yang29@zte.com.cn>
>
> Update group->rtpoll_next_update after called update_triggers() and
> update rtpoll_total. This will prevent bugs if update_triggers() uses
> group->rtpoll_next_update in the future, and it makes more sense
> to set the next update time after we finished the current update.
>
> Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
> Suggested-by: Suren Baghdasaryan <surenb@google.com>

I believe Ingo's version at
https://lore.kernel.org/all/ZScQZLTssSfq19Jm@gmail.com/ already
includes this change.

> ---
>  kernel/sched/psi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> index 143f8eb34f9d..79f8db0c6150 100644
> --- a/kernel/sched/psi.c
> +++ b/kernel/sched/psi.c
> @@ -704,12 +704,12 @@ static void psi_rtpoll_work(struct psi_group *group=
)
>         }
>
>         if (now >=3D group->rtpoll_next_update) {
> -               group->rtpoll_next_update =3D now + group->rtpoll_min_per=
iod;
>                 if (changed_states & group->rtpoll_states) {
>                         update_triggers(group, now, &update_total, PSI_PO=
LL);
>                         memcpy(group->rtpoll_total, group->total[PSI_POLL=
],
>                                    sizeof(group->rtpoll_total));
>                 }
> +               group->rtpoll_next_update =3D now + group->rtpoll_min_per=
iod;
>         }
>
>         psi_schedule_rtpoll_work(group,
> --
> 2.25.1