MIME-Version: 1.0
References: <20211201151844.20488-1-mgorman@techsingularity.net> <20211201151844.20488-2-mgorman@techsingularity.net>
In-Reply-To: <20211201151844.20488-2-mgorman@techsingularity.net>
From:   Barry Song <21cnbao@gmail.com>
Date:   Fri, 3 Dec 2021 21:38:33 +1300
Message-ID: <CAGsJ_4z30yfw=kyBNZuSLMaCcMBmstD=bK4VOsVW3vKO3kO+fA@mail.gmail.com>
Subject: Re: [PATCH 1/2] sched/fair: Use weight of SD_NUMA domain in find_busiest_group
To:     Mel Gorman <mgorman@techsingularity.net>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Aubrey Li <aubrey.li@linux.intel.com>,
        Barry Song <song.bao.hua@hisilicon.com>,
        Mike Galbraith <efault@gmx.de>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
        LKML <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Dec 3, 2021 at 8:27 PM Mel Gorman <mgorman@techsingularity.net> wrote:
>
> find_busiest_group uses the child domain's group weight instead of
> the sched_domain's weight that has SD_NUMA set when calculating the
> allowed imbalance between NUMA nodes. This is wrong and inconsistent
> with find_idlest_group.
>
> This patch uses the SD_NUMA weight in both.
>
> Fixes: c4e8f691d926 ("sched/fair: Adjust the allowed NUMA imbalance when SD_NUMA spans multiple LLCS")

Hi Mel,

sorry I might be missing something. but I have failed to figure out
where this commit is.

> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
> ---
>  kernel/sched/fair.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 6e476f6d9435..0a969affca76 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -9397,7 +9397,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
>                 /* Consider allowing a small imbalance between NUMA groups */
>                 if (env->sd->flags & SD_NUMA) {
>                         env->imbalance = adjust_numa_imbalance(env->imbalance,
> -                               busiest->sum_nr_running, busiest->group_weight);
> +                               busiest->sum_nr_running, env->sd->span_weight);
>                 }
>
>                 return;
> --
> 2.31.1
>

Thanks
Barry