Re: [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix

From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Tao Zhou <tao.zhou@linux.dev>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	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>
Subject: Re: [PATCH V1 RESEND]: sched/fair: Revise comment about lb decision matrix
Date: Fri, 15 Apr 2022 13:33:53 +0200	[thread overview]
Message-ID: <YllYIQXmpqHM0+Wp@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtAbxAerbV-LBcpm_qHAphhD3uU47k0hu=DDX3k6LS-Aow@mail.gmail.com>

On Fri, Apr 15, 2022 at 10:32:09AM +0200, Vincent Guittot wrote:
> On Fri, 15 Apr 2022 at 04:22, Tao Zhou <tao.zhou@linux.dev> wrote:
> >
> > If busiest group type is group_misfit_task, the local
> > group type must be group_has_spare according to below
> > code in update_sd_pick_busiest():
> >
> > if (sgs->group_type == group_misfit_task &&
> >     (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
> >      sds->local_stat.group_type != group_has_spare))
> >          return false;
> >
> > group type imbalanced and overloaded and fully_busy are filtered in here.
> > misfit and asym are filtered before in update_sg_lb_stats().
> 
> The behavior has changed with
> cad68e552e77 ("sched/fair: Consider misfit tasks when load-balancing")
> But we haven't updated the matrix
> 
> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>

Thanks (I took the later version and stuck your Rb on)!