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Date:   Thu, 5 Oct 2023 16:51:52 +0530
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Subject: Re: [External] : Re: [PATCH] cgroup: In cgroup_no_v1() check v1
 controllers only
To:     Tejun Heo <tj@kernel.org>
Cc:     Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Tom Hromatka <tom.hromatka@oracle.com>,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230920102513.55772-1-kamalesh.babulal@oracle.com>
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From:   Kamalesh Babulal <kamalesh.babulal@oracle.com>
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On 10/5/23 00:47, Tejun Heo wrote:
> On Wed, Sep 20, 2023 at 03:55:12PM +0530, Kamalesh Babulal wrote:
>> cgroup v1 or v2 or both controller names can be passed as arguments to
>> the 'cgroup_no_v1' kernel parameter, though most of the controller's
>> names are the same for both cgroup versions. This can be confusing when
>> both versions are used interchangeably, i.e., passing cgroup_no_v1=io
>>
>> $ sudo dmesg |grep cgroup
>> ...
>> cgroup: Disabling io control group subsystem in v1 mounts
>> cgroup: Disabled controller 'blkio'
> 
> So, making the printed names consistent makes sense but I'm not sure about
> not matching "io" anymore. That's gonna break users who already use them,
> right?

Agreed, users might pass "io" in place of "blkio", I was thinking
in terms of cgroup v1 users, for whom it is "blkio" controller but
as an argument, "cgroup_no_v1" makes the controllers passed to it,
available under cgroup v2, where the controller is named "io",
which the user may use interchangeably.

Shall I re-send the patch to print the controller legacy_name only?

-- 
Thanks,
Kamalesh