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 85E3BC43219 for ; Thu, 24 Nov 2022 11:47:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230184AbiKXLrX (ORCPT ); Thu, 24 Nov 2022 06:47:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229610AbiKXLrT (ORCPT ); Thu, 24 Nov 2022 06:47:19 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 813E8AFE60; Thu, 24 Nov 2022 03:47:18 -0800 (PST) Received: from kwepemi500016.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NHx6W4vrMzmW7g; Thu, 24 Nov 2022 19:46:43 +0800 (CST) Received: from [10.174.178.129] (10.174.178.129) by kwepemi500016.china.huawei.com (7.221.188.220) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 24 Nov 2022 19:47:16 +0800 Subject: Re: [PATCH 01/11] blk-throttle: Limit whole system if root group is configured when on the default hierarchy To: Tejun Heo CC: , , , , References: <20221123060401.20392-1-shikemeng@huawei.com> <20221123060401.20392-2-shikemeng@huawei.com> From: Kemeng Shi Message-ID: <2c477253-eb89-260f-adde-5850d749b000@huawei.com> Date: Thu, 24 Nov 2022 19:47:15 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.129] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemi500016.china.huawei.com (7.221.188.220) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org on 11/24/2022 1:11 AM, Tejun Heo wrote: > On Wed, Nov 23, 2022 at 02:03:51PM +0800, Kemeng Shi wrote: >> Quoted from comment in throtl_pd_init: "If on the default hierarchy, we >> switch to properly hierarchical behavior where limits on a given >> throtl_grp are applied to the whole subtree rather than just the group >> itself. e.g. If 16M read_bps limit is set on the root group, the whole >> system can' exceed 16M for the device." > > On the default hierarchy (cgroup2), the throttle interface files don't exist > in the root cgroup. In general, cgroup doesn't wanna be in the business of > restricting resources at the system level. Hi, Tejun. Thanks for review. If restricting is not needed anymore, the stale comment "e.g. If 16M read_bps limit is set on the root group, the whole system can' exceed 16M for the device." may better be remove. I will remove this in next version. -- Best wishes Kemeng Shi