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=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 97B09C433DB for ; Fri, 5 Feb 2021 02:54:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C767764FB5 for ; Fri, 5 Feb 2021 02:53:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C767764FB5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 294296B006C; Thu, 4 Feb 2021 21:53:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 269FF6B006E; Thu, 4 Feb 2021 21:53:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 180556B0070; Thu, 4 Feb 2021 21:53:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0009.hostedemail.com [216.40.44.9]) by kanga.kvack.org (Postfix) with ESMTP id 020256B006C for ; Thu, 4 Feb 2021 21:53:58 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id C436B1EF3 for ; Fri, 5 Feb 2021 02:53:58 +0000 (UTC) X-FDA: 77782694556.11.jar23_250aedc275e1 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id A2D78180F8B81 for ; Fri, 5 Feb 2021 02:53:58 +0000 (UTC) X-HE-Tag: jar23_250aedc275e1 X-Filterd-Recvd-Size: 3613 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Fri, 5 Feb 2021 02:53:57 +0000 (UTC) Received: from DGGEMS412-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4DX0Lv3v6HzMVNg; Fri, 5 Feb 2021 10:52:07 +0800 (CST) Received: from [10.174.179.241] (10.174.179.241) by DGGEMS412-HUB.china.huawei.com (10.3.19.212) with Microsoft SMTP Server id 14.3.498.0; Fri, 5 Feb 2021 10:53:43 +0800 Subject: Re: [PATCH v2] mm: memcontrol: replace the loop with a list_for_each_entry() To: Muchun Song CC: , , , , , , References: <20210204163055.56080-1-songmuchun@bytedance.com> From: Miaohe Lin Message-ID: <6f8d9e82-5903-e983-8c93-9dfe3e9b14ca@huawei.com> Date: Fri, 5 Feb 2021 10:53:42 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210204163055.56080-1-songmuchun@bytedance.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.241] X-CFilter-Loop: Reflected X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi: On 2021/2/5 0:30, Muchun Song wrote: > The rule of list walk has gone since: > > commit a9d5adeeb4b2 ("mm/memcontrol: allow to uncharge page without using page->lru field") > > So remove the strange comment and replace the loop with a > list_for_each_entry(). > > There is only one caller of the uncharge_list(). So just fold it into > mem_cgroup_uncharge_list() and remove it. > > Signed-off-by: Muchun Song LGTM. Thanks. Reviewed-by: Miaohe Lin > --- > v2: > - Fold uncharge_list() to mem_cgroup_uncharge_list(). > > mm/memcontrol.c | 35 ++++++++--------------------------- > 1 file changed, 8 insertions(+), 27 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index ed5cc78a8dbf..8c035846c7a4 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -6862,31 +6862,6 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug) > css_put(&ug->memcg->css); > } > > -static void uncharge_list(struct list_head *page_list) > -{ > - struct uncharge_gather ug; > - struct list_head *next; > - > - uncharge_gather_clear(&ug); > - > - /* > - * Note that the list can be a single page->lru; hence the > - * do-while loop instead of a simple list_for_each_entry(). > - */ > - next = page_list->next; > - do { > - struct page *page; > - > - page = list_entry(next, struct page, lru); > - next = page->lru.next; > - > - uncharge_page(page, &ug); > - } while (next != page_list); > - > - if (ug.memcg) > - uncharge_batch(&ug); > -} > - > /** > * mem_cgroup_uncharge - uncharge a page > * @page: page to uncharge > @@ -6918,11 +6893,17 @@ void mem_cgroup_uncharge(struct page *page) > */ > void mem_cgroup_uncharge_list(struct list_head *page_list) > { > + struct uncharge_gather ug; > + struct page *page; > + > if (mem_cgroup_disabled()) > return; > > - if (!list_empty(page_list)) > - uncharge_list(page_list); > + uncharge_gather_clear(&ug); > + list_for_each_entry(page, page_list, lru) > + uncharge_page(page, &ug); > + if (ug.memcg) > + uncharge_batch(&ug); > } > > /** >