linux-kernel - RE: [patch 0/4] Take care of cpufreq lockdep issues (take 2)

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Message-ID: <7E82351C108FA840AB1866AC776AEC4669BFF052@orsmsx505.amr.corp.intel.com>
Date:	Fri, 3 Jul 2009 07:31:12 -0700
From:	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>
To:	Ingo Molnar <mingo@...e.hu>
CC:	Dave Jones <davej@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	"kernel-testers@...r.kernel.org" <kernel-testers@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Dave Young <hidave.darkstar@...il.com>,
	Pekka Enberg <penberg@...helsinki.fi>,
	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	Thomas Renninger <trenn@...e.de>
Subject: RE: [patch 0/4] Take care of cpufreq lockdep issues (take 2)

 

>-----Original Message-----
>From: Ingo Molnar [mailto:mingo@...e.hu] 
>Sent: Thursday, July 02, 2009 11:54 PM
>To: Pallipadi, Venkatesh
>Cc: Dave Jones; linux-kernel@...r.kernel.org; 
>cpufreq@...r.kernel.org; kernel-testers@...r.kernel.org; 
>Rafael J. Wysocki; Dave Young; Pekka Enberg; Mathieu 
>Desnoyers; Thomas Renninger
>Subject: Re: [patch 0/4] Take care of cpufreq lockdep issues (take 2)
>
>
>* venkatesh.pallipadi@...el.com <venkatesh.pallipadi@...el.com> wrote:
>
>> Since recent chanegs to ondemand and conservative governor, there 
>> have been multiple reports of lockdep issues in cpufreq. Patch 
>> series takes care of these problems.
>> 
>> This is the next attempt following the one here, which was not a 
>> complete fix. 
>> http://lkml.indiana.edu/hypermail/linux/kernel/0906.3/01073.html
>> 
>> I am currently running some stress tests to make sure there are no 
>> issues with these patches. But, wanted to send them out for 
>> review/comments/testing before I head out for the long weekend.
>> 
>> If this patchset seems sane, the first patch in the patchset 
>> should also get into 30.stable.
>
>Btw., FYI, because my test-systems were frequently triggering those 
>bugs, i kept testing the following series from you and Mathieu in 
>-tip:
>
> ecf8b04: cpufreq: Define dbs_mutex purpose and cleanup its 
>usage conservative gov
> b08c597: cpufreq: Define dbs_mutex purpose and cleanup its usage
> 0807e30: cpufreq: remove rwsem lock from CPUFREQ_GOV_STOP 
>call (second call site)
>
>So that fix-series, while probably not complete (given that you sent 
>a v2 series), worked well in practice and gets my:
>
> Tested-by: Ingo Molnar <mingo@...e.hu>
>
>Is the delta between this (tested) series and your v2 version 
>significant? If not it might make sense to shape it as a delta patch 
>to the v1 series, if that looks clean enough - to preserve testing 
>results.
>

Thanks for testing. That earlier version even though it took care
of lockdep complaints, did not address all the race conditions properly.
The delta is significant as I had to change the approach compared
to first patchset. So, diff will not be very clean.

Thanks,
Venki--
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