linux-kernel - Re: [PATCH V3 8/9] cpufreq: Keep policy->freq

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Date:	Mon, 06 Jun 2016 14:10:26 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	Steve Muckle <steve.muckle@...aro.org>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Kukjin Kim <kgene@...nel.org>,
	Shawn Guo <shawn.guo@...escale.com>,
	Steven Miao <realmz6@...il.com>
Subject: Re: [PATCH V3 8/9] cpufreq: Keep policy->freq_table sorted in ascending order

On Monday, June 06, 2016 09:22:31 AM Viresh Kumar wrote:
> On 03-06-16, 16:48, Steve Muckle wrote:
> > On Fri, Jun 03, 2016 at 07:05:14PM +0530, Viresh Kumar wrote:
> > ...
> > > @@ -468,20 +469,15 @@ unsigned int acpi_cpufreq_fast_switch(struct cpufreq_policy *policy,
> > >  	struct acpi_cpufreq_data *data = policy->driver_data;
> > >  	struct acpi_processor_performance *perf;
> > >  	struct cpufreq_frequency_table *entry;
> > > -	unsigned int next_perf_state, next_freq, freq;
> > > +	unsigned int next_perf_state, next_freq, index;
> > >  
> > >  	/*
> > >  	 * Find the closest frequency above target_freq.
> > > -	 *
> > > -	 * The table is sorted in the reverse order with respect to the
> > > -	 * frequency and all of the entries are valid (see the initialization).
> > >  	 */
> > > -	entry = policy->freq_table;
> > > -	do {
> > > -		entry++;
> > > -		freq = entry->frequency;
> > > -	} while (freq >= target_freq && freq != CPUFREQ_TABLE_END);
> > > -	entry--;
> > > +	index = cpufreq_frequency_table_target(policy, target_freq,
> > > +					       CPUFREQ_RELATION_L);
> > 
> > Can we call cpufreq_find_index_l directly here? Seems like we could
> > phase out cpufreq_frequency_table_target() for the most part and call
> > the helpers directly. It would avoid some code bloat, an unnecessary
> > switch statement and an error check for an invalid frequency table which
> > seems unnecessary for every frequency table lookup.
> 
> I agree with that, though that requires larger changes across multiple
> sites.

What changes and where?

> I hope it will be fine if I do it in a separate patch on top of
> all this. Right ?

Depending.