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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 BD281C4361B for ; Thu, 17 Dec 2020 14:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85E3B2360D for ; Thu, 17 Dec 2020 14:00:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727767AbgLQOAn (ORCPT ); Thu, 17 Dec 2020 09:00:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:59582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726488AbgLQOAn (ORCPT ); Thu, 17 Dec 2020 09:00:43 -0500 Date: Thu, 17 Dec 2020 14:59:59 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608213602; bh=svPMXpH6bDkIdejaUcdO9VkfvHen07wvadh8PJV0fLU=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=gerW71+PdJ1eyajH7qobdOXQoi6N5swnm8mDW5oLR0j6UgEIQxj/W9nYT+QA8XKMB sOozaDaRYYdmSyRoZ3Hdz1kj1w+YUeWoV6hc8p0t5+jJsmaU2O/PLcFrk2ILyZ2ssR uye8S3kDU23g7jO/MTqcjP2KvlZYEZjN3X8UEnXHBMuK40AqUtL9n5kQ25s9HNf/jD QasEVpv0Jg0Mpnrh5fsZFQjL2LDRTzM41cyZh/rPFHDACNMaICOVgMJ431/oTL2ea+ lPAAWWzxSgYYUxF+85f/bvZJ6OAR3cXvDgYS4L0PT9SCdLz1m/LXO/Jj/22chXUybX tAwsEoc4u6CHg== From: Frederic Weisbecker To: Yunfeng Ye Cc: fweisbec@gmail.com, tglx@linutronix.de, mingo@kernel.org, linux-kernel@vger.kernel.org, Shiyuan Hu , Hewenliang Subject: Re: [PATCH] tick/nohz: Make the idle_exittime update correctly Message-ID: <20201217135959.GA3736@lothringen> References: <2e194669-c074-069c-4fda-ad5bc313a611@huawei.com> <20201215144757.GA9391@lothringen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks.