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From:   David Dai <davidai@google.com>
Date:   Wed, 5 Apr 2023 15:54:08 -0700
Message-ID: <CABN1KCLjXpxNak90iowd0iiz9SD8-5n+6S3kEoCKO9NantyXxg@mail.gmail.com>
Subject: Re: [RFC PATCH 1/6] sched/fair: Add util_guest for tasks
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Ingo Molnar <mingo@redhat.com>, Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Saravana Kannan <saravanak@google.com>,
        kernel-team@android.com, linux-kernel@vger.kernel.org
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On Wed, Apr 5, 2023 at 1:14=E2=80=AFAM Peter Zijlstra <peterz@infradead.org=
> wrote:
>

Hi Peter,

Appreciate your time,

> On Thu, Mar 30, 2023 at 03:43:36PM -0700, David Dai wrote:
> > @@ -499,6 +509,7 @@ struct sched_avg {
> >       unsigned long                   load_avg;
> >       unsigned long                   runnable_avg;
> >       unsigned long                   util_avg;
> > +     unsigned long                   util_guest;
> >       struct util_est                 util_est;
> >  } ____cacheline_aligned;
> >
>
> Yeah, no... you'll have to make room first.
>

I=E2=80=99m not sure what you mean. Do you mean making room by reducing
another member in the same struct? If so, which member would be a good
fit to shorten? Or do you mean something else entirely?

Thanks,
David

> struct sched_avg {
>         /* typedef u64 -> __u64 */ long long unsigned int     last_update=
_time;          /*     0     8 */
>         /* typedef u64 -> __u64 */ long long unsigned int     load_sum;  =
                /*     8     8 */
>         /* typedef u64 -> __u64 */ long long unsigned int     runnable_su=
m;              /*    16     8 */
>         /* typedef u32 -> __u32 */ unsigned int               util_sum;  =
                /*    24     4 */
>         /* typedef u32 -> __u32 */ unsigned int               period_cont=
rib;            /*    28     4 */
>         long unsigned int          load_avg;                             =
                /*    32     8 */
>         long unsigned int          runnable_avg;                         =
                /*    40     8 */
>         long unsigned int          util_avg;                             =
                /*    48     8 */
>         struct util_est {
>                 unsigned int       enqueued;                             =
                /*    56     4 */
>                 unsigned int       ewma;                                 =
                /*    60     4 */
>         } __attribute__((__aligned__(8)))util_est __attribute__((__aligne=
d__(8))); /*    56     8 */
>
>         /* size: 64, cachelines: 1, members: 9 */
>         /* forced alignments: 1 */
> } __attribute__((__aligned__(64)));
>
>