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Date: Wed, 2 Apr 2025 14:02:21 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>, Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
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	Valentin Schneider <vschneid@redhat.com>,
	Frederic Weisbecker <fweisbecker@suse.com>
Subject: Re: [PATCH v2 06/10] sched: Bypass bandwitdh checks with runtime
 disabled RT_GROUP_SCHED
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References: <20250310170442.504716-1-mkoutny@suse.com>
 <20250310170442.504716-7-mkoutny@suse.com>
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In-Reply-To: <20250310170442.504716-7-mkoutny@suse.com>

On Mon, Mar 10, 2025 at 06:04:38PM +0100, Michal Koutný wrote:
> When RT_GROUPs are compiled but not exposed, their bandwidth cannot
> be configured (and it is not initialized for non-root task_groups neither).
> Therefore bypass any checks of task vs task_group bandwidth.
> 
> This will achieve behavior very similar to setups that have
> !CONFIG_RT_GROUP_SCHED and attach cpu controller to cgroup v2 hierarchy.
> (On a related note, this may allow having RT tasks with
> CONFIG_RT_GROUP_SCHED and cgroup v2 hierarchy.)

Can we make it so that cgroup-v2 is explicitly disallowed for now? As I
said earlier, we're looking at a new implemention with a incompatible
interface.