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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT 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 1254FC433E1 for ; Tue, 11 Aug 2020 11:11:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF1852078E for ; Tue, 11 Aug 2020 11:11:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728689AbgHKLK7 (ORCPT ); Tue, 11 Aug 2020 07:10:59 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:50903 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728659AbgHKLK5 (ORCPT ); Tue, 11 Aug 2020 07:10:57 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01422;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0U5TLMT5_1597144252; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U5TLMT5_1597144252) by smtp.aliyun-inc.com(127.0.0.1); Tue, 11 Aug 2020 19:10:53 +0800 From: Alex Shi To: akpm@linux-foundation.org Cc: "Kirill A. Shutemov" , Johannes Weiner , Matthew Wilcox , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [Resend PATCH 5/6] mm/thp: remove code path which never got into Date: Tue, 11 Aug 2020 19:10:31 +0800 Message-Id: <1597144232-11370-5-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1597144232-11370-1-git-send-email-alex.shi@linux.alibaba.com> References: <1597144232-11370-1-git-send-email-alex.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org split_huge_page() will never call on a page which isn't on lru list, so this code never got a chance to run, and should not be run, to add tail pages on a lru list which head page isn't there. Although the bug was never triggered, it'better be removed for code correctness, and add a warn for unexpected calling. Signed-off-by: Alex Shi Reviewed-by: Kirill A. Shutemov Cc: Kirill A. Shutemov Cc: Andrew Morton Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Hugh Dickins Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/huge_memory.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8cecd39bd8b7..d55e3006c63f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2332,17 +2332,8 @@ static void lru_add_page_tail(struct page *head, struct page *page_tail, /* page reclaim is reclaiming a huge page */ get_page(page_tail); list_add_tail(&page_tail->lru, list); - } else { - /* - * Head page has not yet been counted, as an hpage, - * so we must account for each subpage individually. - * - * Put page_tail on the list at the correct position - * so they all end up in order. - */ - add_page_to_lru_list_tail(page_tail, lruvec, - page_lru(page_tail)); - } + } else + VM_WARN_ON(!PageLRU(head)); } static void __split_huge_page_tail(struct page *head, int tail, -- 1.8.3.1