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 13119C4332F for ; Fri, 30 Sep 2022 08:32:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230424AbiI3Icc (ORCPT ); Fri, 30 Sep 2022 04:32:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbiI3Ic3 (ORCPT ); Fri, 30 Sep 2022 04:32:29 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7690E3AE7C for ; Fri, 30 Sep 2022 01:32:27 -0700 (PDT) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Mf3M23kc9zHqVr; Fri, 30 Sep 2022 16:30:06 +0800 (CST) Received: from [10.67.110.25] (10.67.110.25) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 30 Sep 2022 16:32:25 +0800 Message-ID: Date: Fri, 30 Sep 2022 16:32:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.1.2 Subject: Re: [PATCH] sched/fair: limit burst to zero when cfs bandwidth is toggled off From: "zhaowenhui (A)" To: , , , , CC: , , , , , , , , , , References: <20220809120320.19496-1-zhaowenhui8@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.110.25] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500022.china.huawei.com (7.185.36.162) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/8/30 11:19, zhaowenhui (A) 写道: > > > 在 2022/8/9 20:03, Zhao Wenhui 写道: >> When the quota value in CFS bandwidth is set to -1, that imples the >> cfs bandwidth is toggled off. So the burst feature is supposed to >> be disable as well. >> >> Currently, when quota is -1, burst will not be check, so that it can be >> set to almost arbitery value. Examples: >>          mkdir /sys/fs/cgroup/cpu/test >>          echo -1 > /sys/fs/cgroup/cpu/test/cpu.cfs_quota_us >>          echo 10000000000000000 > >> /sys/fs/cgroup/cpu/test/cpu.cfs_burst_us >> >> Moreover, after the burst modified by this way, quota can't be set >> to any value: >>          echo 100000 > cpu.cfs_quota_us >>          -bash: echo: write error: Invalid argument >> >> This patch can ensure the burst value being zero and unalterable, >> when quota is set to -1. >> >> Fixes: f4183717b370 ("sched/fair: Introduce the burstable CFS >> controller") >> Reported-by: Zhao Gongyi >> Signed-off-by: Zhao Wenhui >> --- >>   kernel/sched/core.c | 10 +++++++++- >>   1 file changed, 9 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/sched/core.c b/kernel/sched/core.c >> index ee28253c9ac0..4c1fc01d8c68 100644 >> --- a/kernel/sched/core.c >> +++ b/kernel/sched/core.c >> @@ -10584,6 +10584,12 @@ static int tg_set_cfs_bandwidth(struct >> task_group *tg, u64 period, u64 quota, >>                        burst + quota > max_cfs_runtime)) >>           return -EINVAL; >> +    /* >> +     * Ensure burst equals to zero when quota is -1. >> +     */ >> +    if (quota == RUNTIME_INF && burst) >> +        return -EINVAL; >> + >>       /* >>        * Prevent race between setting of cfs_rq->runtime_enabled and >>        * unthrottle_offline_cfs_rqs(). >> @@ -10643,8 +10649,10 @@ static int tg_set_cfs_quota(struct task_group >> *tg, long cfs_quota_us) >>       period = ktime_to_ns(tg->cfs_bandwidth.period); >>       burst = tg->cfs_bandwidth.burst; >> -    if (cfs_quota_us < 0) >> +    if (cfs_quota_us < 0) { >>           quota = RUNTIME_INF; >> +        burst = 0; >> +    } >>       else if ((u64)cfs_quota_us <= U64_MAX / NSEC_PER_USEC) >>           quota = (u64)cfs_quota_us * NSEC_PER_USEC; >>       else > > Gentle ping. > > Thanks, > Zhao Wenhui Dear Maintainers, Hi, this patch has been reviewed by two reviewers over a month ago. So, Any more suggestions for this patch or it can be picked? Regards, Zhao Wenhui