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Message-ID: <1100a740-3da4-a5bd-6a98-49b49c97b11b@redhat.com>
Date:   Tue, 4 Apr 2023 13:26:10 -0400
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Subject: Re: [PATCH 1/3] cgroup/cpuset: Make cpuset_fork() handle
 CLONE_INTO_CGROUP properly
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From:   Waiman Long <longman@redhat.com>
To:     =?UTF-8?Q?Michal_Koutn=c3=bd?= <mkoutny@suse.com>
Cc:     Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Christian Brauner <brauner@kernel.org>,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        Juri Lelli <juri.lelli@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        gscrivan@redhat.com
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On 4/4/23 09:52, Waiman Long wrote:
>
> On 4/4/23 05:19, Michal Koutný wrote:
>> On Mon, Apr 03, 2023 at 01:18:42PM -0400, Waiman Long 
>> <longman@redhat.com> wrote:
>>> 1) PF_NO_SETAFFINITY flag - which won't be set in the case of fork() 
>>> as it
>>> is for kthread only.
>>> 2) DL bandwidth - Juri has a cpuset outstanding to modify the way 
>>> this check
>>> is being done. I want to wait until it is settled before tackling 
>>> this, if
>>> necessary.
>> BTW what about CLONE_INTO_CGROUP where the target cpuset has empty
>> effective cpuset?
> Good point. That will require a can_fork() method then. I will look 
> into that.
>>
>>> 3) security_task_setscheduler() - the CLONE_INTO_CGROUP code has 
>>> already
>>> checked that, we don't need to duplicate the check.
>> Not sure what this refers to.
> It is just checking of the task the has privilege of running into that 
> cgroup.
>>
>>> So we don't need a can_fork() check for now.
>> Anyway, good breakdown. Could you please add it to the commit message
>> too?
>
> Yes, I can put that into the commit log.

I decide to add the can_fork method to do a pre-check. So I don't think 
I need to update the commit log of this patch.

Cheers,
Longman