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 X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81465C4361B for ; Fri, 18 Dec 2020 00:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 499A0238A0 for ; Fri, 18 Dec 2020 00:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732017AbgLRAzY (ORCPT ); Thu, 17 Dec 2020 19:55:24 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:9537 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731747AbgLRAzY (ORCPT ); Thu, 17 Dec 2020 19:55:24 -0500 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Cxr3G2JDkzhp6S; Fri, 18 Dec 2020 08:54:02 +0800 (CST) Received: from [10.174.176.199] (10.174.176.199) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.498.0; Fri, 18 Dec 2020 08:54:33 +0800 Subject: Re: [PATCH] tick/nohz: Make the idle_exittime update correctly To: Frederic Weisbecker CC: , , , , Shiyuan Hu , Hewenliang References: <2e194669-c074-069c-4fda-ad5bc313a611@huawei.com> <20201215144757.GA9391@lothringen> <20201217135959.GA3736@lothringen> From: Yunfeng Ye Message-ID: <58b1fd2e-e2a2-ab7f-33e5-71e0e5653578@huawei.com> Date: Fri, 18 Dec 2020 08:54:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20201217135959.GA3736@lothringen> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.176.199] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/12/17 21:59, Frederic Weisbecker wrote: > On Thu, Dec 17, 2020 at 02:51:58PM +0800, Yunfeng Ye wrote: >> >> >> On 2020/12/15 22:47, Frederic Weisbecker wrote: >>> On Tue, Dec 15, 2020 at 08:06:34PM +0800, Yunfeng Ye wrote: >>>> The idle_exittime field of tick_sched is used to record the time when >>>> the idle state was left. but currently the idle_exittime is updated in >>>> the function tick_nohz_restart_sched_tick(), which is not always in idle >>>> state when nohz_full is configured. >>>> >>>> tick_irq_exit >>>> tick_nohz_irq_exit >>>> tick_nohz_full_update_tick >>>> tick_nohz_restart_sched_tick >>>> ts->idle_exittime = now; >>>> >>>> So move to tick_nohz_stop_idle() to make the idle_exittime update >>>> correctly. >>>> >>>> Signed-off-by: Yunfeng Ye >>>> --- >>>> kernel/time/tick-sched.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c >>>> index 749ec2a583de..be2e5d772d50 100644 >>>> --- a/kernel/time/tick-sched.c >>>> +++ b/kernel/time/tick-sched.c >>>> @@ -591,6 +591,7 @@ static void tick_nohz_stop_idle(struct tick_sched *ts, ktime_t now) >>>> { >>>> update_ts_time_stats(smp_processor_id(), ts, now, NULL); >>>> ts->idle_active = 0; >>>> + ts->idle_exittime = now; >>> >>> This changes a bit the meaning of idle_exittime then since this is also called >>> from idle interrupt entry. >>> >>> __tick_nohz_idle_restart_tick() would be a better place. >>> >> So is it necessary to modify the comment "@idle_exittime: Time when the idle state was left" ? >> >> On the other hand, if the patch "nohz: Update tick instead of restarting tick in tick_nohz_idle_exit()" >> (https://www.spinics.net/lists/kernel/msg3747039.html ) applied, __tick_nohz_idle_restart_tick will not >> be called always, So is it put here also a better place? > > Right but I need to re-order some code before. That's ok, I'll integrate this > patch inside the changes. > Ok, thanks. > Thanks. > . >