Re: [PATCH/RFC] Have sane default values for cpusets

From: Dhaval Giani
Date: Wed May 12 2010 - 10:13:58 EST


[Please do *NOT* drop the cc list]

On Wed, May 12, 2010 at 4:11 PM, James Kosin <jkosin@xxxxxxxxxxxxx> wrote:
> On 5/12/2010 9:50 AM, Dhaval Giani wrote:
>> On Wed, May 12, 2010 at 3:40 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>>> On Wed, 2010-05-12 at 15:05 +0200, Dhaval Giani wrote:
>>>> Where cpusets goes wrong is to have a *no* default values.
>>>
>>> It has a default, empty is still a valid value.
>>>
>>
>> Well, it is still not sane. And in the part you snipped, I did mention,
>>
>>>> do we enforce a policy to have sane defaults
>>>> for subsystems if they prevent attaching "regular" tasks by default.
>>
>> And to add to it, a sane default can be defined as one, where a task
>> can be attached to a cgroup on creation without changing any other
>> parameter.
>>
>> Dhaval
>
> By keeping the insane policy, we force everyone to properly setup to
> sane defaults.  By automatically inheriting the defaults, we would be
> introducing the possibility of a lazy programmer forgetting to setup the
> proper defaults for their application which may need different values
> than the inherited settings.  This would lead to ensuing chaos eventually.

Nope. Not really. What you are saying is that an application
programmer who wants to just use memory cgroups should also care about
cpusets and just about countless other cgroup subsystems that can
exist. A lazy programmer not setting up a sane value for what he cares
about will see abnormal execution of his application and be able to
fix it.

You are talking about moving the burden of setup to the people who
should be least concerned about it.

Dhaval
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/