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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,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 083F0C47083 for ; Mon, 24 May 2021 09:25:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9A119610C7 for ; Mon, 24 May 2021 09:25:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9A119610C7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2237C940061; Mon, 24 May 2021 05:25:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1FA69940055; Mon, 24 May 2021 05:25:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0C2AF940061; Mon, 24 May 2021 05:25:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0188.hostedemail.com [216.40.44.188]) by kanga.kvack.org (Postfix) with ESMTP id CD053940055 for ; Mon, 24 May 2021 05:25:39 -0400 (EDT) Received: from smtpin33.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 703CC181AEF30 for ; Mon, 24 May 2021 09:25:39 +0000 (UTC) X-FDA: 78175591998.33.CF47F10 Received: from outbound-smtp02.blacknight.com (outbound-smtp02.blacknight.com [81.17.249.8]) by imf17.hostedemail.com (Postfix) with ESMTP id C9D3F40F8C01 for ; Mon, 24 May 2021 09:25:35 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp02.blacknight.com (Postfix) with ESMTPS id 71038BAD64 for ; Mon, 24 May 2021 10:25:32 +0100 (IST) Received: (qmail 26618 invoked from network); 24 May 2021 09:25:32 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.23.168]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 24 May 2021 09:25:32 -0000 Date: Mon, 24 May 2021 10:25:30 +0100 From: Mel Gorman To: Dave Hansen Cc: Linux-MM , Dave Hansen , Matthew Wilcox , Vlastimil Babka , Michal Hocko , Nicholas Piggin , LKML Subject: Re: [PATCH 6/6] mm/page_alloc: Introduce vm.percpu_pagelist_high_fraction Message-ID: <20210524092530.GE30378@techsingularity.net> References: <20210521102826.28552-1-mgorman@techsingularity.net> <20210521102826.28552-7-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: C9D3F40F8C01 Authentication-Results: imf17.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf17.hostedemail.com: domain of mgorman@techsingularity.net designates 81.17.249.8 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net X-Rspamd-Server: rspam04 X-Stat-Signature: i4qjrefnnkx88j7qwy7rhep4qq7pxkmc X-HE-Tag: 1621848335-151131 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 Fri, May 21, 2021 at 03:57:20PM -0700, Dave Hansen wrote: > On 5/21/21 3:28 AM, Mel Gorman wrote: > > This introduces a new sysctl vm.percpu_pagelist_high_fraction. It is > > similar to the old vm.percpu_pagelist_fraction except it only adjusts > > pcp->high to potentially reduce zone->lock contention while preserving > > allocation latency when PCP lists have to be refilled. > > Look at me... Five patches later and I already forgot what the old one > did and why it stinks. I wonder if you might do a wee bit of compare > and contrast. Something like: > > The old vm.percpu_pagelist_fraction increased both the batch and > high limits for the per-cpu page allocator. Its worst feature > was that it led to absurdly large batch sizes that incurred > nasty worst-case allocation latency. > > This new sysctl in comparison... > > Anyway, the approach looks sound to me. The batch size isn't important > now, especially given the auto-scaling in patch 4. > > Acked-by: Dave Hansen Thanks, I updated the changelog and hopefully it is better. -- Mel Gorman SUSE Labs