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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 44679C43215 for ; Fri, 22 Nov 2019 15:50:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1354520714 for ; Fri, 22 Nov 2019 15:50:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1354520714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.page Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 860026B050E; Fri, 22 Nov 2019 10:50:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 810706B050F; Fri, 22 Nov 2019 10:50:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 724466B0510; Fri, 22 Nov 2019 10:50:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id 5A4306B050E for ; Fri, 22 Nov 2019 10:50:16 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id E4D9C181AEF21 for ; Fri, 22 Nov 2019 15:50:15 +0000 (UTC) X-FDA: 76184349990.20.price26_76ac211b9fe26 X-HE-Tag: price26_76ac211b9fe26 X-Filterd-Recvd-Size: 2675 Received: from relay11.mail.gandi.net (relay11.mail.gandi.net [217.70.178.231]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Fri, 22 Nov 2019 15:50:15 +0000 (UTC) Received: from localhost (unknown [153.3.140.100]) (Authenticated sender: fly@kernel.page) by relay11.mail.gandi.net (Postfix) with ESMTPSA id CA1E1100010; Fri, 22 Nov 2019 15:49:31 +0000 (UTC) Date: Fri, 22 Nov 2019 23:49:07 +0800 From: Pengfei Li To: David Hildenbrand Cc: akpm@linux-foundation.org, mgorman@techsingularity.net, mhocko@kernel.org, vbabka@suse.cz, cl@linux.com, iamjoonsoo.kim@lge.com, guro@fb.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, fly@kernel.page Subject: Re: [RFC v1 00/19] Modify zonelist to nodelist v1 Message-ID: <20191122234907.4da3bc81.fly@kernel.page> In-Reply-To: <1bb37491-72a7-feaa-722d-a5825813a409@redhat.com> References: <20191121151811.49742-1-fly@kernel.page> <1bb37491-72a7-feaa-722d-a5825813a409@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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, 22 Nov 2019 11:03:30 +0100 David Hildenbrand wrote: > On 21.11.19 16:17, Pengfei Li wrote: > > Motivation > > ---------- > > Currently if we want to iterate through all the nodes we have to > > traverse all the zones from the zonelist. > > > > So in order to reduce the number of loops required to traverse node, > > this series of patches modified the zonelist to nodelist. > > > > Two new macros have been introduced: > > 1) for_each_node_nlist > > 2) for_each_node_nlist_nodemask > > > > > > Benefit > > ------- > > 1. For a NUMA system with N nodes, each node has M zones, the number > > of loops is reduced from N*M times to N times when traversing > > node. > > > > 2. The size of pg_data_t is much reduced. > > > > > > Test Result > > ----------- > > Currently I have only performed a simple page allocation benchmark > > test on my laptop, and the results show that the performance of a > > system with only one node is almost unaffected. > > > > So you are seeing no performance changes. I am wondering why do we > need this, then - because your motivation sounds like a performance > improvement? (not completely against this, just trying to understand > the value of this :) ) Thanks for your comments. I am sorry that I did not make it clear. I want to express this series of patches will benefit NUMA systems with multiple nodes. The main benefit is that it will be more efficient when traversing all nodes (for example when performing page reclamation).