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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42EE8C433F5 for ; Mon, 25 Apr 2022 12:09:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BB53F6B0074; Mon, 25 Apr 2022 08:09:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B61756B0075; Mon, 25 Apr 2022 08:09:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A514A6B0078; Mon, 25 Apr 2022 08:09:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 972E36B0074 for ; Mon, 25 Apr 2022 08:09:09 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 7E27B62CB3 for ; Mon, 25 Apr 2022 12:09:09 +0000 (UTC) X-FDA: 79395280818.11.036C7B4 Received: from gentwo.de (gentwo.de [161.97.139.209]) by imf27.hostedemail.com (Postfix) with ESMTP id 8627740041 for ; Mon, 25 Apr 2022 12:09:07 +0000 (UTC) Received: by gentwo.de (Postfix, from userid 1001) id 94730B000C1; Mon, 25 Apr 2022 14:09:06 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by gentwo.de (Postfix) with ESMTP id 938E4B00078; Mon, 25 Apr 2022 14:09:06 +0200 (CEST) Date: Mon, 25 Apr 2022 14:09:06 +0200 (CEST) From: Christoph Lameter To: Aaron Tomlin cc: frederic@kernel.org, mtosatti@redhat.com, tglx@linutronix.de, mingo@kernel.org, peterz@infradead.org, pauld@redhat.com, neelx@redhat.com, oleksandr@natalenko.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v3] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too In-Reply-To: <20220425113909.u3smtztp66svlw4o@ava.usersys.com> Message-ID: References: <20220422193647.3808657-1-atomlin@redhat.com> <20220425113909.u3smtztp66svlw4o@ava.usersys.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Stat-Signature: etyp4gur7n3u3qkf86soacteg8cjrpbx Authentication-Results: imf27.hostedemail.com; dkim=none; spf=pass (imf27.hostedemail.com: domain of cl@gentwo.de designates 161.97.139.209 as permitted sender) smtp.mailfrom=cl@gentwo.de; dmarc=pass (policy=none) header.from=gentwo.de X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 8627740041 X-HE-Tag: 1650888547-275494 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 25 Apr 2022, Aaron Tomlin wrote: > Yes, in the context of nohz, this patch should ensure it, if required, when > the idle tick is to be stopped. What I said was that it is generally useful. Even in the non NOHZ case. Folding the vmstat diffs *always* when entering idle prevents unnecessary wakeups and processing in the future and also provides more accurate counters for the VM allowing better decision to be made on reclaim.