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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 2F4D7C433E6 for ; Wed, 24 Feb 2021 20:06:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D756464F23 for ; Wed, 24 Feb 2021 20:06:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233576AbhBXUGO (ORCPT ); Wed, 24 Feb 2021 15:06:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:56740 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234364AbhBXUFd (ORCPT ); Wed, 24 Feb 2021 15:05:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2AF9364F0F; Wed, 24 Feb 2021 20:04:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614197049; bh=5c8za154E5ZZs1Pe0YPwFgF4ghXJ/O1bpaJjs3eUP5A=; h=Date:From:To:Subject:In-Reply-To:From; b=jxs6EAW4b50ev3OUu2zJH/HgrNQ2gHhIk6ZP92Df0amnoJfoACQC23RwLJAHI1/Fs KtGiuPbRk8HJtCnW90z+rzdWd8Kpt/j8OpI6duke/Ckny7ksTo3N4K+WBchFdhmt2b 7r5nP1b3THPM3huKc4uhmu5HGf0F72m0Qu35GMSA= Date: Wed, 24 Feb 2021 12:04:08 -0800 From: Andrew Morton To: akpm@linux-foundation.org, guro@fb.com, hannes@cmpxchg.org, linmiaohe@huawei.com, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, songmuchun@bytedance.com, torvalds@linux-foundation.org Subject: [patch 070/173] mm: memcontrol: replace the loop with a list_for_each_entry() Message-ID: <20210224200408.tuzvi2hBn%akpm@linux-foundation.org> In-Reply-To: <20210224115824.1e289a6895087f10c41dd8d6@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Muchun Song Subject: mm: memcontrol: replace the loop with a list_for_each_entry() 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. Link: https://lkml.kernel.org/r/20210204163055.56080-1-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Johannes Weiner Acked-by: Roman Gushchin Reviewed-by: Miaohe Lin Acked-by: Michal Hocko Signed-off-by: Andrew Morton --- mm/memcontrol.c | 35 ++++++++--------------------------- 1 file changed, 8 insertions(+), 27 deletions(-) --- a/mm/memcontrol.c~mm-memcontrol-replace-the-loop-with-a-list_for_each_entry +++ a/mm/memcontrol.c @@ -6862,31 +6862,6 @@ static void uncharge_page(struct page *p 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 *pa */ 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); } /** _