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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59B20EE4996 for ; Mon, 21 Aug 2023 08:50:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234175AbjHUIuR (ORCPT ); Mon, 21 Aug 2023 04:50:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234159AbjHUIuQ (ORCPT ); Mon, 21 Aug 2023 04:50:16 -0400 Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A9C6C1 for ; Mon, 21 Aug 2023 01:50:14 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046051;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VqF1WK9_1692607809; Received: from 30.97.48.69(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VqF1WK9_1692607809) by smtp.aliyun-inc.com; Mon, 21 Aug 2023 16:50:10 +0800 Message-ID: <9749af5b-8c0b-49e4-d76e-129736472499@linux.alibaba.com> Date: Mon, 21 Aug 2023 16:50:10 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: [PATCH 0/4] Extend migrate_misplaced_page() to support batch migration To: "Huang, Ying" Cc: akpm@linux-foundation.org, mgorman@techsingularity.net, shy828301@gmail.com, david@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <87cyzhdt5r.fsf@yhuang6-desk2.ccr.corp.intel.com> <21099f59-c660-41a3-e422-0c14ac5d0fac@linux.alibaba.com> <87r0nwdbxw.fsf@yhuang6-desk2.ccr.corp.intel.com> From: Baolin Wang In-Reply-To: <87r0nwdbxw.fsf@yhuang6-desk2.ccr.corp.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/21/2023 4:41 PM, Huang, Ying wrote: > Baolin Wang writes: > >> On 8/21/2023 10:29 AM, Huang, Ying wrote: >>> Baolin Wang writes: >>> >>>> Hi, >>>> >>>> Currently, on our ARM servers with NUMA enabled, we found the cross-die latency >>>> is a little larger that will significantly impact the workload's performance. >>>> So on ARM servers we will rely on the NUMA balancing to avoid the cross-die >>>> accessing. And I posted a patchset[1] to support speculative numa fault to >>>> improve the NUMA balancing's performance according to the principle of data >>>> locality. Moreover, thanks to Huang Ying's patchset[2], which introduced batch >>>> migration as a way to reduce the cost of TLB flush, and it will also benefit >>>> the migration of multiple pages all at once during NUMA balancing. >>>> >>>> So we plan to continue to support batch migration in do_numa_page() to improve >>>> the NUMA balancing's performance, but before adding complicated batch migration >>>> algorithm for NUMA balancing, some cleanup and preparation work need to do firstly, >>>> which are done in this patch set. In short, this patchset extends the >>>> migrate_misplaced_page() interface to support batch migration, and no functional >>>> changes intended. >>> Will these cleanup benefit anything except batching migration? If >>> not, >> >> I hope these cleanup can also benefit the compound page's NUMA >> balancing, which was discussed in the thread[1]. IIUC, for the >> compound page's NUMA balancing, it is possible that partial pages were >> successfully migrated, so it is necessary to return the number of >> pages that were successfully migrated from >> migrate_misplaced_page(). (But I did not look this in detail yet, >> please correct me if I missed something, and I will find some time to >> look this in detail). That is why I think these cleanups are >> straightforward. >> >> Yes, I will post the batch migration patches after more polish and >> testing, but I think these cleanups are separate and straightforward, >> so I plan to submit the patches separately. > > Then, please state the benefit explicitly in the patch description > instead of just preparation for batching migration. Sure, will do. Thanks.