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 36655C433EF for ; Thu, 17 Feb 2022 14:47:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242058AbiBQOsD (ORCPT ); Thu, 17 Feb 2022 09:48:03 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:59130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242049AbiBQOsA (ORCPT ); Thu, 17 Feb 2022 09:48:00 -0500 X-Greylist: delayed 137 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 17 Feb 2022 06:47:43 PST Received: from p3plsmtpa11-04.prod.phx3.secureserver.net (p3plsmtpa11-04.prod.phx3.secureserver.net [68.178.252.105]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D630615E6E3 for ; Thu, 17 Feb 2022 06:47:43 -0800 (PST) Received: from localhost ([82.17.115.212]) by :SMTPAUTH: with ESMTPA id Ki28n316uQeWgKi2AnNP8p; Thu, 17 Feb 2022 07:45:26 -0700 X-CMAE-Analysis: v=2.4 cv=Fa7yeLy6 c=1 sm=1 tr=0 ts=620e5f86 a=9gipVNR6X1CoIeAWHwLoWw==:117 a=9gipVNR6X1CoIeAWHwLoWw==:17 a=IkcTkHD0fZMA:10 a=r5m66G8ZfA9aYF3hFTkA:9 a=QEXdDO2ut3YA:10 X-SECURESERVER-ACCT: atomlin@atomlin.com Date: Thu, 17 Feb 2022 14:45:24 +0000 From: Aaron Tomlin To: Frederic Weisbecker Cc: Aaron Tomlin , Phil Auld , tglx@linutronix.de, mingo@kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too Message-ID: <20220217144524.el7lwi45hwsf3ef2@ava.usersys.com> References: <20220203214339.1889971-1-atomlin@redhat.com> <20220216143412.dwxjlkq4w2zeweld@ava.usersys.com> <20220217125731.GA744754@lothringen> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220217125731.GA744754@lothringen> X-CMAE-Envelope: MS4xfLkWofOShUPdAv6/WMzdpwZTNw5VpOKWtXuAJawWtOZ7Rms7HwLXEwraAp/eqA7/7AcSC81edXfGXBhmpxJxyhkrNwi8JMZRHFXhuQv1hiJ/0kYhTy/s +aiknQJNXvx3+KiX+0CNIC/8IxRsRwn304CHwtTt4ve0Ibe1yRsLxlw4Mq6OsaJdpiaY6f8B+8sbtlGF22V+TvCV4CzAQkJj3TnbwLk0nhdYAFHZZPR9WK+/ tiZMQtciczwUoiGX9bs7RT+SyHqtzqIM/3VGnGDM2rGT71izV3WzdTE8queJ5ZTEC8jZ/U00jUXQHehO8cMl+D7czfcG74hFNh1Yw601RSWoNNsI8DNa8Z5D trS24NvvmF28cVGHalXRjNIOPWrVQvANrFO/vZf4VAALog3qGeM= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 2022-02-17 13:57 +0100, Frederic Weisbecker wrote: > Hmm, but does it matter? The issue seem to be that we can enter in idle loop without > flushing vmstat. Or am I missing something else? Frederic, Yes, this is indeed the concern. So, the idea I had was to invoke quiet_vmstat() regardless if the tick was stopped or not. If I understand correctly, this should resolve the issue. Furthermore, folding of all outstanding differentials will only occur when required. Thus performance should be negligible. Kind regards, -- Aaron Tomlin