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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 7B9C3C41604 for ; Tue, 6 Oct 2020 22:34:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C2B9C208FE for ; Tue, 6 Oct 2020 22:34:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C2B9C208FE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1118C6B005D; Tue, 6 Oct 2020 18:34:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0C27E6B0062; Tue, 6 Oct 2020 18:34:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F1A846B006C; Tue, 6 Oct 2020 18:34:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0165.hostedemail.com [216.40.44.165]) by kanga.kvack.org (Postfix) with ESMTP id C16B46B005D for ; Tue, 6 Oct 2020 18:34:40 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 6358D1EE6 for ; Tue, 6 Oct 2020 22:34:40 +0000 (UTC) X-FDA: 77342956320.24.son81_270aff2271ca Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 47E601A4A7 for ; Tue, 6 Oct 2020 22:34:40 +0000 (UTC) X-HE-Tag: son81_270aff2271ca X-Filterd-Recvd-Size: 2302 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf20.hostedemail.com (Postfix) with ESMTP for ; Tue, 6 Oct 2020 22:34:39 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AB32BAC5F; Tue, 6 Oct 2020 22:34:38 +0000 (UTC) Subject: Re: [PATCH 6/9] mm, page_alloc: cache pageset high and batch in struct zone To: Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Pavel Tatashin , David Hildenbrand , Oscar Salvador , Joonsoo Kim References: <20200922143712.12048-1-vbabka@suse.cz> <20200922143712.12048-7-vbabka@suse.cz> <20201005132830.GB4555@dhcp22.suse.cz> From: Vlastimil Babka Message-ID: <017450b3-21b1-a6a0-adea-b0b4fa1870d3@suse.cz> Date: Wed, 7 Oct 2020 00:34:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201005132830.GB4555@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000078, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 10/5/20 3:28 PM, Michal Hocko wrote: > On Tue 22-09-20 16:37:09, Vlastimil Babka wrote: >> All per-cpu pagesets for a zone use the same high and batch values, that are >> duplicated there just for performance (locality) reasons. This patch adds the >> same variables also to struct zone as a shared copy. >> >> This will be useful later for making possible to disable pcplists temporarily >> by setting high value to 0, while remembering the values for restoring them >> later. But we can also immediately benefit from not updating pagesets of all >> possible cpus in case the newly recalculated values (after sysctl change or >> memory online/offline) are actually unchanged from the previous ones. > > Advantage of this patch is not really clear from it in isolation. Maybe > merge it with the patch which uses the duplicated state. I'm not sure that would help its reviewability? As the patch that uses it is the last, largest one. And there is already a small advantage right away as changelog explains.