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 EC7C2EB64DC for ; Wed, 21 Jun 2023 08:36:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231129AbjFUIg1 (ORCPT ); Wed, 21 Jun 2023 04:36:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbjFUIgX (ORCPT ); Wed, 21 Jun 2023 04:36:23 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29BBE186 for ; Wed, 21 Jun 2023 01:36:20 -0700 (PDT) Received: from dggpemm100001.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4QmGzX2mwBzTlQS; Wed, 21 Jun 2023 16:35:36 +0800 (CST) Received: from [10.174.177.243] (10.174.177.243) by dggpemm100001.china.huawei.com (7.185.36.93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Wed, 21 Jun 2023 16:36:17 +0800 Message-ID: Date: Wed, 21 Jun 2023 16:36:17 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH -next v2 1/2] mm: compaction: convert to use a folio in isolate_migratepages_block() Content-Language: en-US To: Baolin Wang , CC: , , , , References: <20230619110718.65679-1-wangkefeng.wang@huawei.com> From: Kefeng Wang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm100001.china.huawei.com (7.185.36.93) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/6/21 14:20, Baolin Wang wrote: > Hi > > On 6/19/2023 7:07 PM, Kefeng Wang wrote: >> Directly use a folio instead of page_folio() when page successfully >> isolated (hugepage and movable page) and after folio_get_nontail_page(), >> which removes several calls to compound_head(). >> >> Signed-off-by: Kefeng Wang >> --- >> v2: >> - update comments and use node_stat_mod_folio, per Matthew Wilcox >> - add missed PageLRU conversion and rebase on next-20230619 >> >>   mm/compaction.c | 84 ++++++++++++++++++++++++++----------------------- >>   1 file changed, 44 insertions(+), 40 deletions(-) >> >> diff --git a/mm/compaction.c b/mm/compaction.c >> index 6149a2d324be..0334eefe4bfa 100644 >> --- a/mm/compaction.c >> +++ b/mm/compaction.c >> @@ -795,6 +795,7 @@ isolate_migratepages_block(struct compact_control >> *cc, unsigned long low_pfn, >>       struct lruvec *lruvec; >>       unsigned long flags = 0; >>       struct lruvec *locked = NULL; >> +    struct folio *folio = NULL; >>       struct page *page = NULL, *valid_page = NULL; >>       struct address_space *mapping; >>       unsigned long start_pfn = low_pfn; >> @@ -891,7 +892,7 @@ isolate_migratepages_block(struct compact_control >> *cc, unsigned long low_pfn, >>           if (!valid_page && pageblock_aligned(low_pfn)) { >>               if (!isolation_suitable(cc, page)) { >>                   low_pfn = end_pfn; >> -                page = NULL; >> +                folio = NULL; >>                   goto isolate_abort; >>               } >>               valid_page = page; >> @@ -923,7 +924,8 @@ isolate_migratepages_block(struct compact_control >> *cc, unsigned long low_pfn, >>                    * Hugepage was successfully isolated and placed >>                    * on the cc->migratepages list. >>                    */ >> -                low_pfn += compound_nr(page) - 1; >> +                folio = page_folio(page); >> +                low_pfn += folio_nr_pages(folio) - 1; >>                   goto isolate_success_no_list; >>               } >> @@ -991,8 +993,10 @@ isolate_migratepages_block(struct compact_control >> *cc, unsigned long low_pfn, >>                       locked = NULL; >>                   } >> -                if (isolate_movable_page(page, mode)) >> +                if (isolate_movable_page(page, mode)) { >> +                    folio = page_folio(page); >>                       goto isolate_success; >> +                } >>               } >>               goto isolate_fail; >> @@ -1003,7 +1007,8 @@ isolate_migratepages_block(struct >> compact_control *cc, unsigned long low_pfn, >>            * sure the page is not being freed elsewhere -- the >>            * page release code relies on it. >>            */ >> -        if (unlikely(!get_page_unless_zero(page))) >> +        folio = folio_get_nontail_page(page); > > I'm just curious, how can you make sure the 'page' is not a tail page? > Since the validation is lockless. folio_get_nontail_page is added by commit "3c1ea2c729ef (mm: add folio_get_nontail_page())", see more comments [1] [1] https://lore.kernel.org/lkml/Y86sRiKAAOz2myNe@casper.infradead.org/ >