From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EB72EC8740 for ; Thu, 7 Sep 2023 16:22:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240868AbjIGQWT (ORCPT ); Thu, 7 Sep 2023 12:22:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241540AbjIGQVv (ORCPT ); Thu, 7 Sep 2023 12:21:51 -0400 Received: from smtp-fw-9102.amazon.com (smtp-fw-9102.amazon.com [207.171.184.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33A5F7DB4; Thu, 7 Sep 2023 09:19:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1694103549; x=1725639549; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=YauVF01CGBBHBYehJqzxf4f2JW+5DIf+1r8++cg5PLM=; b=P3QAX8zLOfeNlSVYnBk8O4LKH1ZDrrYYpF7e5PWyUIqFknEMHKC+gYga X84diM7Dk2gbtoCGXb6REJd4vyV+MHnc34nVKwcSA65wAwYGeBDizqPML 1Vcv/VNfXx/WGrSyHxxdk9memcIdxNSV4jeJi4m2QchDIFctqwQm09Pkz 4=; X-IronPort-AV: E=Sophos;i="6.02,235,1688428800"; d="scan'208";a="362200815" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-pdx-2a-m6i4x-83883bdb.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2023 15:17:01 +0000 Received: from EX19MTAUEA001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2a-m6i4x-83883bdb.us-west-2.amazon.com (Postfix) with ESMTPS id DB24460DBE; Thu, 7 Sep 2023 15:17:00 +0000 (UTC) Received: from EX19D028UEC003.ant.amazon.com (10.252.137.159) by EX19MTAUEA001.ant.amazon.com (10.252.134.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Thu, 7 Sep 2023 15:16:45 +0000 Received: from [192.168.204.203] (10.252.141.11) by EX19D028UEC003.ant.amazon.com (10.252.137.159) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Thu, 7 Sep 2023 15:16:44 +0000 Message-ID: <236f84be-26b0-758d-3d3f-380e536f72c2@amazon.com> Date: Thu, 7 Sep 2023 11:16:41 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: [PATH v2] cgroup: add cgroup_favordynmods= command-line option Content-Language: en-US To: =?UTF-8?Q?Michal_Koutn=c3=bd?= CC: , , , , , , References: <20230906005712.66461-1-luizcap@amazon.com> From: Luiz Capitulino In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.252.141.11] X-ClientProxiedBy: EX19D036UWC001.ant.amazon.com (10.13.139.233) To EX19D028UEC003.ant.amazon.com (10.252.137.159) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023-09-07 11:06, Michal Koutný wrote: > On Wed, Sep 06, 2023 at 12:57:12AM +0000, Luiz Capitulino wrote: >> We have a need of using favordynmods with cgroup v1, which doesn't support >> changing mount flags during remount. Enabling CONFIG_FAVOR_DYNMODS at >> build-time is not an option because we want to be able to selectively >> enable it for certain systems. > > Could this be implemented by a utility that would read /proc/cmdline > (while kernel ignores the arg) and remount respective hierarchies > accordingly? Or what do I miss? Yeah, this works for cgroup v2 but my understanding is that cgroup v1 doesn't support changing flags in remount, take a look at cgroup1_reconfigure(). - Luiz