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 D893CC433EF for ; Fri, 24 Jun 2022 09:36:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231512AbiFXJgY (ORCPT ); Fri, 24 Jun 2022 05:36:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232178AbiFXJgS (ORCPT ); Fri, 24 Jun 2022 05:36:18 -0400 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AED05794DD for ; Fri, 24 Jun 2022 02:36:08 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0VHGmXek_1656063365; Received: from 30.97.49.29(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VHGmXek_1656063365) by smtp.aliyun-inc.com; Fri, 24 Jun 2022 17:36:06 +0800 Message-ID: Date: Fri, 24 Jun 2022 17:36:07 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH 3/7] migrate_pages(): fix THP failure counting for -ENOMEM To: Huang Ying , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zi Yan , Yang Shi References: <20220624025309.1033400-1-ying.huang@intel.com> <20220624025309.1033400-4-ying.huang@intel.com> From: Baolin Wang In-Reply-To: <20220624025309.1033400-4-ying.huang@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 6/24/2022 10:53 AM, Huang Ying wrote: > In unmap_and_move(), if the new THP cannot be allocated, -ENOMEM will > be returned, and migrate_pages() will try to split the THP unless > "reason" is MR_NUMA_MISPLACED (that is, nosplit == true). But when > nosplit == true, the THP migration failure will not be counted. This > is incorrect. So in this patch, the THP migration failure will be > counted for -ENOMEM regardless of nosplit is true or false. The > nr_failed counting is fixed too, although that is not used actually. No strong opinion about the 'nr_failed' updating, like you said, we did not use it in this case. Maybe just add some comments instead of adding some unused code? Otherwise looks good to me. Reviewed-by: Baolin Wang > > Signed-off-by: "Huang, Ying" > Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages") > Cc: Baolin Wang > Cc: Zi Yan > Cc: Yang Shi > --- > mm/migrate.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 82444e7df9f1..542533e4e3cf 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1425,11 +1425,11 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > /* > * When memory is low, don't bother to try to migrate > * other pages, just exit. > - * THP NUMA faulting doesn't split THP to retry. > */ > - if (is_thp && !nosplit) { > + if (is_thp) { > nr_thp_failed++; > - if (!try_split_thp(page, &thp_split_pages)) { > + /* THP NUMA faulting doesn't split THP to retry. */ > + if (!nosplit && !try_split_thp(page, &thp_split_pages)) { > nr_thp_split++; > goto retry; > } > @@ -1446,6 +1446,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > */ > list_splice_init(&thp_split_pages, from); > nr_thp_failed += thp_retry; > + if (!no_subpage_counting) > + nr_failed += retry; > goto out; > case -EAGAIN: > if (is_thp)