Date: Mon, 26 Jun 2017 17:04:01 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org, jhladky@redhat.com, mingo@kernel.org,
        mgorman@suse.de
Subject: Re: [PATCH 4/4] sched,fair: remove effective_load
Message-ID: <20170626150401.GC4941@worktop>
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 <20170623165530.22514-5-riel@redhat.com>
 <20170626144437.GB4941@worktop>
 <20170626144611.GA5775@worktop>
 <1498488941.13083.43.camel@redhat.com>
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On Mon, Jun 26, 2017 at 10:55:41AM -0400, Rik van Riel wrote:
> On Mon, 2017-06-26 at 16:46 +0200, Peter Zijlstra wrote:
> > On Mon, Jun 26, 2017 at 04:44:37PM +0200, Peter Zijlstra wrote:
> > > On Fri, Jun 23, 2017 at 12:55:30PM -0400, riel@redhat.com wrote:
> > > > From: Rik van Riel <riel@redhat.com>
> > > > 
> > > > The function effective_load was only used by the NUMA balancing
> > > > code, and not by the regular load balancing code. Now that the
> > > > NUMA balancing code no longer uses it either, get rid of it.
> > > 
> > > Hmm,... funny. It used to be used by wake-affine. I'll have to go
> > > check
> > > what happened.
> > 
> > Ah, it fell pray to that LLC == NUMA confusion from the previous
> > patch.
> > 
> > That really looks buggered.
> 
> Do the changelog or comments of that patch need fixing,
> to avoid LLC / NUMA confusion?

Neither, I think the code is actually wrong for the case where LLC <
NUMA (a somewhat rare case these days, granted, but something that might
still happen on !x86 perhaps).