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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0500ECAAD5 for ; Sat, 27 Aug 2022 02:27:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 651EB940007; Fri, 26 Aug 2022 22:27:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 604506B0075; Fri, 26 Aug 2022 22:27:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4C8BD940007; Fri, 26 Aug 2022 22:27:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 3931C6B0074 for ; Fri, 26 Aug 2022 22:27:52 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 10F3980590 for ; Sat, 27 Aug 2022 02:27:52 +0000 (UTC) X-FDA: 79843787184.22.359B8E3 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf08.hostedemail.com (Postfix) with ESMTP id 4D8F7160006 for ; Sat, 27 Aug 2022 02:27:51 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4MF0rZ1607z1N7MB; Sat, 27 Aug 2022 10:24:14 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 27 Aug 2022 10:27:47 +0800 Subject: Re: [PATCH 03/10] hugetlb: Use LIST_HEAD() to define a list head To: Muchun Song CC: Andrew Morton , , Muchun Song , , References: <20220826092422.39591-1-linmiaohe@huawei.com> <20220826092422.39591-4-linmiaohe@huawei.com> <8D011A6F-F557-4519-852C-80BBDE53E630@linux.dev> From: Miaohe Lin Message-ID: Date: Sat, 27 Aug 2022 10:27:46 +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: <8D011A6F-F557-4519-852C-80BBDE53E630@linux.dev> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661567271; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZKiBtkVGAI/B12URVGu7dMx+Xpptw0nOVC2wrpzZ5pQ=; b=zfAXOrsIrDR5K8bljkwrfCnXLOdL3zG1hDRnb6bBAw4PAruj/man9G4ClrdxhJWgiAcYl2 y1Rs7HmVS1nRKBH8J5U2cN63QA+lr3WglleinR0s4km265R/Wt5n9e2Kiey55fqH34ixn7 fewlWcSbPw4vIVrF+KjKWu6aNLvgdcU= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661567271; a=rsa-sha256; cv=none; b=IXjoq5cZd2TvtrTtxXxoUhhYE79Co8Nic3RNxcrZ8bkky17Xgv56rFpZU3PHIxhifIOcDK /d8czDElzzIr7ngiv2W1GFa0luw5DzHehKwHbc+AqTs37D5kDaDKeRfCwWmQjrEpOGQBnZ wTM21L7ZqCf4tJZcrMaPLo/ZbVW3ueE= X-Rspam-User: Authentication-Results: imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspamd-Server: rspam05 X-Stat-Signature: w9bjj8pxnttck6cqyrobn7nfygpxjhgk X-Rspamd-Queue-Id: 4D8F7160006 X-HE-Tag: 1661567271-615145 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: On 2022/8/27 9:47, Muchun Song wrote: > > >> On Aug 26, 2022, at 17:24, Miaohe Lin wrote: >> >> We can avoid unneeded WRITE_ONCE() overhead by using LIST_HEAD() to define >> a list head. > > IIUC, the overhead doesn’t change. Right? I think the overhead is changed. LIST_HEAD is initialized without using WRITE_ONCE(): #define LIST_HEAD_INIT(name) { &(name), &(name) } #define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) while INIT_LIST_HEAD has: static inline void INIT_LIST_HEAD(struct list_head *list) { WRITE_ONCE(list->next, list); WRITE_ONCE(list->prev, list); } Or am I miss something? > > I’m fine with your changes. > > Reviewed-by: Muchun Song Many thanks for your review and comment. :) Thanks, Miaohe Lin