From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C4F314534B2 for ; Tue, 28 Apr 2026 18:02:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777399345; cv=none; b=Y0pDdvuswVXkPIH3A3/UPbX2bz4PhWsPqH6ASMF1Aom629mBv/0SS78fXhCa2rYQ+4/ULLhcU12gy22tCTGmHJ8mlst2PjM9hTZLQrQwbrrZ5FdeeBRsut97Qzkt0HadhabjRHmdz1QdJ1iY9Xm11COvh9zPFLLMzXdDvwSnn4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777399345; c=relaxed/simple; bh=dYGwWwtkKlPo1deJLx9BodMTvAxpwgOxdsVgFmjZsoM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=imB0WBmqBzryqxYoAALczIfyTml+KJqLZUOmAGgJ9y50UG9d3jPsUwAskWOJ8wFbYUswEJZQpZO8KGmCf3ZyhFjSPddeqML7PK9PceTxN1Oky+VJfAIgG7xbh8IhrI4hYUvIXjcYQvMfLD42mX/zo5mbr0TCM1oiFBOWXKkfwP8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=N+ZQXjDe; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="N+ZQXjDe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777399342; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ajb3tIPe2Fnx33E4Ll33pwLtSHp6m0qrFpGOVd8lamo=; b=N+ZQXjDeyRIUim2e4d9mDGs4e2/iurq2pkOJxMTm5i5k29KhFIfoIb0a65U8soC8oWTwsg s/TjiinRnb2aEl8hOuDmqc5ynxAQwfXnbww7nz75qa7mn/XKq8U3wslZcGWB759CzBNUEl BFGP3Gv0C2hV7IkkQZ5ME3IG0HwM30o= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-644-Ws1fpmuWNLuZhhR_lu7h5g-1; Tue, 28 Apr 2026 14:02:17 -0400 X-MC-Unique: Ws1fpmuWNLuZhhR_lu7h5g-1 X-Mimecast-MFC-AGG-ID: Ws1fpmuWNLuZhhR_lu7h5g_1777399334 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 42DE4186016B; Tue, 28 Apr 2026 18:02:13 +0000 (UTC) Received: from [10.22.65.177] (unknown [10.22.65.177]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 3674D1800671; Tue, 28 Apr 2026 18:02:11 +0000 (UTC) Message-ID: <973442ef-ad08-4503-8afc-c97d07298c61@redhat.com> Date: Tue, 28 Apr 2026 14:02:10 -0400 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] cgroup/cpuset: Creating or adding CPUs to partition not allowed without privilege To: Tejun Heo Cc: =?UTF-8?Q?Michal_Koutn=C3=BD?= , Chen Ridong , Johannes Weiner , Jonathan Corbet , Shuah Khan , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Xie Maoyi References: <20260428033439.783246-1-longman@redhat.com> <7so4b76wg2apwwk3yh76q42jgwnpvlv7sursmsmzeyefhp4pbt@thybpp4litm6> <9df75f61-0cbb-42b4-b64d-8e6fd49d50ca@redhat.com> Content-Language: en-US From: Waiman Long In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On 4/28/26 11:44 AM, Tejun Heo wrote: > Hello, > > On Tue, Apr 28, 2026 at 11:19:16AM -0400, Waiman Long wrote: > ... >> Thank for the comment. Yes, that can be a valid configuration. >> >> One possible workaround may be to see if the current user has write access >> to its parent partition root. If so, we can allow it to create a >> sub-partition, if not, we will forbid it. > I think this whole thing is a confusion. First of all, resource knobs in any > given cgroup is owned by the parent. Delegations where the perm to a > resource knob is given to delegatee is not supported and expected to affect > resource distribution w.r.t. its siblings. Partition isn't special in this > regard. memory.low or min can create similar effects. Maybe I'm missing > something but I don't see anything happening that's not supposed to happen. You are right. I am a bit confused about the exact delegation rules. After reading the delegation section of the cgroup-v2.rst file, I realize that the current behavior should be OK. For clarity, I am planning to send a documentation patch to clarify the current partition delegation behavior. Thanks, Longman