Re: [PATCH 1/5] cgroup/cpuset: Don't call validate_change() for some flag changes

Waiman Long
2021-06-17T02:53:55Z

On 6/16/21 4:39 PM, Tejun Heo wrote:
> Hello,
>
> On Thu, Jun 03, 2021 at 05:24:12PM -0400, Waiman Long wrote:
>> The update_flag() is called with one flag bit change and without change
>> in the various cpumasks in the cpuset. Moreover, not all changes in the
>> flag bits are validated in validate_change(). In particular, the load
>> balance flag and the two spread flags are not checked there. So there
>> is no point in calling validate_change() if those flag bits change.
> The fact that it's escaping validation conditionally from caller side is
> bothersome given that the idea is to have self-contained verifier to ensure
> correctness. I'd prefer to make the validation more complete and optimized
> (ie. detect or keep track of what changed) if really necessary rather than
> escaping partially because certain conditions aren't checked.

Thanks for the comments.

You are right. I will leave out this patch. Anyway, the rests of the
patchset don't have a strict dependency on it.

Cheers,
Longman