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=-15.3 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=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 644C5C433DB for ; Tue, 26 Jan 2021 11:06:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31B2323104 for ; Tue, 26 Jan 2021 11:06:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404985AbhAZLGs (ORCPT ); Tue, 26 Jan 2021 06:06:48 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:11877 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732496AbhAZGVM (ORCPT ); Tue, 26 Jan 2021 01:21:12 -0500 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4DPxQG71Q8z7b5G; Tue, 26 Jan 2021 14:19:02 +0800 (CST) Received: from [10.174.179.117] (10.174.179.117) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.498.0; Tue, 26 Jan 2021 14:20:10 +0800 Subject: Re: [PATCH] mm: hugetlb: fix missing put_page in gather_surplus_pages() To: Muchun Song CC: , , , , , References: <20210126031009.96266-1-songmuchun@bytedance.com> From: Miaohe Lin Message-ID: Date: Tue, 26 Jan 2021 14:20:10 +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: <20210126031009.96266-1-songmuchun@bytedance.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.117] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi: On 2021/1/26 11:10, Muchun Song wrote: > The VM_BUG_ON_PAGE avoids the generation of any code, even if that > expression has side-effects when !CONFIG_DEBUG_VM. > > Fixes: e5dfacebe4a4 ("mm/hugetlb.c: just use put_page_testzero() instead of page_count()") > Signed-off-by: Muchun Song > Cc: > --- > mm/hugetlb.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index a6bad1f686c5..082ed643020b 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -2047,13 +2047,16 @@ static int gather_surplus_pages(struct hstate *h, long delta) > > /* Free the needed pages to the hugetlb pool */ > list_for_each_entry_safe(page, tmp, &surplus_list, lru) { > + int zeroed; > + > if ((--needed) < 0) > break; > /* > * This page is now managed by the hugetlb allocator and has > * no users -- drop the buddy allocator's reference. > */ > - VM_BUG_ON_PAGE(!put_page_testzero(page), page); > + zeroed = put_page_testzero(page); > + VM_BUG_ON_PAGE(!zeroed, page); > enqueue_huge_page(h, page); > } > free: > Good Catch! Thanks. Reviewed-by: Miaohe Lin