linux-kernel - Re: [PATCH 1/8] sched/cpufreq: remove cpufreq_trigger

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Message-ID: <20160315214941.GN6344@twins.programming.kicks-ass.net>
Date:	Tue, 15 Mar 2016 22:49:41 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Michael Turquette <mturquette@...libre.com>
Cc:	rjw@...ysocki.net, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org, Juri.Lelli@....com,
	steve.muckle@...aro.org, morten.rasmussen@....com,
	dietmar.eggemann@....com, vincent.guittot@...aro.org,
	Michael Turquette <mturquette+renesas@...libre.com>
Subject: Re: [PATCH 1/8] sched/cpufreq: remove cpufreq_trigger_update()

On Tue, Mar 15, 2016 at 02:45:45PM -0700, Michael Turquette wrote:
> Quoting Peter Zijlstra (2016-03-15 14:14:48)
> > On Sun, Mar 13, 2016 at 10:22:05PM -0700, Michael Turquette wrote:
> > > cpufreq_trigger_update() was introduced in "cpufreq: Rework the
> > > scheduler hooks for triggering updates"[0]. Consensus is that this
> > > helper is not needed and removing it will aid in experimenting with
> > > deadline and rt capacity requests.
> > > 
> > > Instead of reverting the above patch, which includes useful renaming of
> > > data structures and related functions, simply remove the function,
> > > update affected kerneldoc and change rt.c and deadline.c to use
> > > cpufreq_update_util().
> > 
> > This fails to explain how the need for these hooks is dealt with.
> 
> Sorry, I don't understand your point. The removed hook,
> "cpufreq_trigger_update()" was only used in deadline.c and rt.c, and
> this patch effectively reverts Rafael's patch that introduces that
> function.
> 
> It simply does not revert the other changes in Rafael's patch, such as
> some renaming.
> 
> deadline.c and rt.c are made to use cpufreq_update_util() and pass in
> ULONG_MAX for capacity and 0 for time. This is exactly what they did
> before patch "cpufreq: Rework the scheduler hooks for triggering
> updates".

Clearly I need to learn to read again.. You're right.