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 1CC87C00528 for ; Wed, 2 Aug 2023 11:10:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232895AbjHBLKA (ORCPT ); Wed, 2 Aug 2023 07:10:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232756AbjHBLJ6 (ORCPT ); Wed, 2 Aug 2023 07:09:58 -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 7DBA62102 for ; Wed, 2 Aug 2023 04:09:54 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0Vout75S_1690974590; Received: from 30.97.48.77(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0Vout75S_1690974590) by smtp.aliyun-inc.com; Wed, 02 Aug 2023 19:09:51 +0800 Message-ID: <58c4cef1-ebba-6aa9-bdef-19470f7d2ce8@linux.alibaba.com> Date: Wed, 2 Aug 2023 19:10:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v2 1/8] mm/compaction: avoid missing last page block in section after skip offline sections To: Kemeng Shi , linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mgorman@techsingularity.net, david@redhat.com References: <20230802093741.2333325-1-shikemeng@huaweicloud.com> <20230802093741.2333325-2-shikemeng@huaweicloud.com> From: Baolin Wang In-Reply-To: <20230802093741.2333325-2-shikemeng@huaweicloud.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 8/2/2023 5:37 PM, Kemeng Shi wrote: > skip_offline_sections_reverse will return the last pfn in found online > section. Then we set block_start_pfn to start of page block which > contains the last pfn in section. Then we continue, move one page > block forward and ignore the last page block in the online section. > Make block_start_pfn point to first page block after online section to fix > this: > 1. make skip_offline_sections_reverse return end pfn of online section, > i.e. pfn of page block after online section. > 2. assign block_start_pfn with next_pfn. > > Fixes: f63224525309 ("mm: compaction: skip the memory hole rapidly when isolating free pages") The changes look good to me. But the commit id is not stable, since it is not merged into mm-stable branch yet. Not sure how to handle this patch, squash it into the original patch? Andrew, what do you prefer? > Signed-off-by: Kemeng Shi > --- > mm/compaction.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index cd23da4d2a5b..a8cea916df9d 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -250,6 +250,11 @@ static unsigned long skip_offline_sections(unsigned long start_pfn) > return 0; > } > > +/* > + * If the PFN falls into an offline section, return the end PFN of the > + * next online section in reverse. If the PFN falls into an online section > + * or if there is no next online section in reverse, return 0. > + */ > static unsigned long skip_offline_sections_reverse(unsigned long start_pfn) > { > unsigned long start_nr = pfn_to_section_nr(start_pfn); > @@ -259,7 +264,7 @@ static unsigned long skip_offline_sections_reverse(unsigned long start_pfn) > > while (start_nr-- > 0) { > if (online_section_nr(start_nr)) > - return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION - 1; > + return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION; > } > > return 0; > @@ -1668,8 +1673,7 @@ static void isolate_freepages(struct compact_control *cc) > > next_pfn = skip_offline_sections_reverse(block_start_pfn); > if (next_pfn) > - block_start_pfn = max(pageblock_start_pfn(next_pfn), > - low_pfn); > + block_start_pfn = max(next_pfn, low_pfn); > > continue; > }