linux-kernel - Re: [PATCH -v2 03/18] sched/fair: Cure calc_cfs_shares() vs reweight

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Message-ID: <20170929130033.GA16286@e105550-lin.cambridge.arm.com>
Date:   Fri, 29 Sep 2017 14:00:34 +0100
From:   Morten Rasmussen <morten.rasmussen@....com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     mingo@...nel.org, linux-kernel@...r.kernel.org, tj@...nel.org,
        josef@...icpanda.com, torvalds@...ux-foundation.org,
        vincent.guittot@...aro.org, efault@....de, pjt@...gle.com,
        clm@...com, dietmar.eggemann@....com, bsegall@...gle.com,
        yuyang.du@...el.com
Subject: Re: [PATCH -v2 03/18] sched/fair: Cure calc_cfs_shares() vs
 reweight_entity()

On Fri, Sep 29, 2017 at 01:38:53PM +0200, Peter Zijlstra wrote:
> On Fri, Sep 29, 2017 at 10:04:34AM +0100, Morten Rasmussen wrote:
> 
> > > -	load = scale_load_down(cfs_rq->load.weight);
> > > +	load = max(scale_load_down(cfs_rq->load.weight), cfs_rq->avg.load_avg);
> > 
> > We use cfs_rq->tg_load_avg_contrib (the filtered version of
> > cfs_rq->avg.load_avg) instead of cfs_rq->avg.load_avg further down, so I
> > think we should here too for consistency.
> > 
> > +	load = max(scale_load_down(cfs_rq->load.weight),
> > +		   cfs_rq->tg_load_avg_contrib);
> > 
> 
> No; we must use tg_load_avg_contrib because that is what's inclded in
> tg_weight, but we want to add the most up-to-date value back in.

Agreed. Looking at it again it make sense.