linux-kernel - Re: [PATCH 3/3] cpufreq: Remove unnecessary use of policy->shared

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAKohponEsSrwLWbi4WJ19i8XkzEiL0De2ShLePBdygunmGEo5g@mail.gmail.com>
Date:	Fri, 1 Feb 2013 12:43:12 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Santosh Shilimkar <santosh.shilimkar@...com>
Cc:	rjw@...k.pl, cpufreq@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linaro-dev@...ts.linaro.org,
	robin.randhawa@....com, Steve.Bannister@....com,
	Liviu.Dudau@....com, Linus Walleij <linus.walleij@...aro.org>,
	Stephen Warren <swarren@...dia.com>,
	Shawn Guo <shawn.guo@...aro.org>
Subject: Re: [PATCH 3/3] cpufreq: Remove unnecessary use of policy->shared_type

On 1 February 2013 12:17, Santosh Shilimkar <santosh.shilimkar@...com> wrote:
> I haven't looked at the cpufreq code recently but remember
> that it was needed to ensure that all the CPU which
> share clock/voltage gets updated (affected cpus) on
> freq change. The CPUs which needs SW co-ordination, should
> have this flag enabled and OMAP was falling in that category.

Freq change are done by the target routines of platform cpufreq drivers
and they do something like:

	for_each_cpu(freqs.cpu, policy->cpus)
		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

The only requirement from cpufreq core is to keep cpus sharing clock
in policy->cpus.

> May be I miss-understood its use, but can you confirm that
> SW co-ordination logic continues to work without this flag ?

I believe it should work. It works for the systems i worked on:

SPEAr13xx: Dual Cortex A9
ARM TC2: two clusters of A15s and A7s.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/