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Date: Tue, 9 May 2017 11:37:30 +0200
From: Luca Abeni <luca.abeni@santannapisa.it>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@arm.com>,
        Claudio Scordino <claudio@evidence.eu.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Tommaso Cucinotta <tommaso.cucinotta@sssup.it>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Joel Fernandes <joelaf@google.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>
Subject: Re: [RFC v5 8/9] sched/deadline: base GRUB reclaiming on the
 inactive utilization
Message-ID: <20170509113730.4a940865@luca>
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On Mon, 8 May 2017 10:06:13 +0200
Peter Zijlstra <peterz@infradead.org> wrote:
[...]
> > > #define BW_SHIFT	20
> > > #define BW_UNIT		(1 << BW_SHIFT)
> > > 
> > > static inline
> > > u64 grub_reclaim(u64 delta, struct rq *rq, struct sched_dl_entity
> > > *dl_se) {
> > > u64 u_inact = rq->dl.this_bw - rq->dl.running_bw; /* Utot -
> > > Uact */ u64 u_act;  
> > [...]
> > 
> > I think introducing the BW_SHIFT and BW_UNIT defines can be more
> > useful in a previous patch (patch 4, where I introduce the
> > "grub_reclaim()" function, and use ">> 20" for the first time.  
> 
> Sure..
> 
> > Moreover, the "20" magic number is already used in core.c... Should
> > I introduce the defines in sched/sched.h, and change the existing
> > core.c code too?  
> 
> Yes please.
> 
> > Is it ok to embed this change in patch 4 (sched/deadline:
> > implement GRUB accounting), or should it go in a separate patch?  
> 
> Whatever you feel is nicest. Currently the thing is fully contained in
> the one to_ratio() function (afaict), so the first patch where you
> make it escape would be fine.

Ok, thanks. I included this change in patch 4 (the first one using the
"20") and I put the two defines in sched.h, immediately before the
prototype of to_ratio().

I am finishing with the requested changes, and after some days of
testing I'll post a new patchset.


			Thanks,
				Luca