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 9326BC433DB for ; Fri, 19 Feb 2021 11:26:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 254D264E67 for ; Fri, 19 Feb 2021 11:26:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 254D264E67 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 831D58D001F; Fri, 19 Feb 2021 06:26:44 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 808C58D000A; Fri, 19 Feb 2021 06:26:44 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 71DF58D001F; Fri, 19 Feb 2021 06:26:44 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0211.hostedemail.com [216.40.44.211]) by kanga.kvack.org (Postfix) with ESMTP id 559EE8D000A for ; Fri, 19 Feb 2021 06:26:44 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 1473F12DC for ; Fri, 19 Feb 2021 11:26:44 +0000 (UTC) X-FDA: 77834789928.22.10BDE55 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf04.hostedemail.com (Postfix) with ESMTP id 3C88CD5 for ; Fri, 19 Feb 2021 11:26:42 +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 451EEACCF; Fri, 19 Feb 2021 11:26:42 +0000 (UTC) Subject: Re: [PATCH RFC 0/1] mm: balancing the node zones occupancy To: Charan Teja Reddy , akpm@linux-foundation.org, rientjes@google.com, mhocko@suse.com, david@redhat.com, mgorman@techsingularity.net, linux-mm@kvack.org Cc: vinmenon@codeaurora.org, sudaraja@codeaurora.org, linux-kernel@vger.kernel.org, Dave Hansen References: From: Vlastimil Babka Message-ID: <1c445421-ddeb-8768-03d0-81537b0d1875@suse.cz> Date: Fri, 19 Feb 2021 12:26:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 3C88CD5 X-Stat-Signature: bzknknocfpncxgxidg3ja1cxyx1qzx1r Received-SPF: none (suse.cz>: No applicable sender policy available) receiver=imf04; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1613734002-256922 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000306, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2/18/21 6:24 PM, Charan Teja Reddy wrote: > I would like to start discussion about balancing the occupancy of > memory zones in a node in the system whose imabalance may be caused by > migration of pages to other zones during hotremove and then hotadding > same memory. In this case there is a lot of free memory in newly hotadd > memory which can be filled up by the previous migrated pages(as part of > offline/hotremove) thus may free up some pressure in other zones of the > node. Can you share the use case for doing this? If it's to replace a failed RAM, then it's probably extremely rare, right. > We have the proof-of-concept code tried on the Snapdragon systems with > the system configuration, single memory node of just 2 zones, 6GB normal > zone and 2GB movable zone. And this Movable zone is such that hot-added > once and there after offline/online based on the need. Hm, snapdragon... so is this some kind of power saving thing? Anyway, shouln't auto NUMA balancing help here, and especially "Migrate Pages in lieu of discard" (CC'd Dave) as a generic mechanism, so we wouldn't need to have hotplug-specific actions?