Re: [PATCH 0/3] cpufreq: governor: Fix potential races

[Preeti U Murthy <preeti@linux.vnet.ibm.com>]

On 06/05/2015 08:30 AM, Viresh Kumar wrote:
> On 04-06-15, 10:44, Preeti U Murthy wrote:
>> On 06/03/2015 03:57 PM, Viresh Kumar wrote:
>>> Preeti recently highlighted [1] some issues in cpufreq core locking with
>>> respect to governors. I wanted to solve them after we have simplified
>>> the hotplug paths in cpufreq core with my latest patches, but now that
>>> she has poked me, I have done some work in that area.
>>>
>>> I am trying to solve only a part of the bigger problem (in a way that I
>>> feel is the right way ahead). The first patches restructures code to
>>> make it more readable and the last patch does all the major changes. The
>>> logs in that one should be good enough to explain why and what I am
>>> doing.
>>>
>>> The first two shouldn't bring any functional change and so can be
>>> applied early if you are confident about them.
>>>
>>> @Preeti: I would like you to test these patches. These should get rid of
>>> the crashes you were facing but may generate a WARN() from line 447 of
>>> cpufreq_governor.c, if the sequence is wrong. That has to be fixed
>>> separately.
>>>
>>> Line 447: WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT))
> 
> Hi Preeti,
> 
> Thanks for giving your RBY tags for all the patches, would you also
> like to give Tested-by's if you have done any testing on these.
> 
> That is just to confirm it hasn't broken things any further and that
> we haven't seen any crashes in races between
> INIT/EXIT/START/STOP/LIMITS.
> 

Let me run a fair bit of tests today and confirm this.

Regards
Preeti U Murthy