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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 455D1C43441 for ; Thu, 22 Nov 2018 10:56:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0837C20820 for ; Thu, 22 Nov 2018 10:56:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0837C20820 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394383AbeKVVfn (ORCPT ); Thu, 22 Nov 2018 16:35:43 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:47772 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732079AbeKVVfn (ORCPT ); Thu, 22 Nov 2018 16:35:43 -0500 Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 6A828D19FE95E; Thu, 22 Nov 2018 18:56:40 +0800 (CST) Received: from [10.151.23.176] (10.151.23.176) by smtp.huawei.com (10.3.19.210) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 22 Nov 2018 18:56:31 +0800 Subject: Re: [PATCH 05/10] staging: erofs: add a full barrier in erofs_workgroup_unfreeze To: Greg Kroah-Hartman CC: , , Chao Yu , LKML , , Miao Xie References: <20181120143425.43637-1-gaoxiang25@huawei.com> <20181120143425.43637-6-gaoxiang25@huawei.com> <20181122102230.GF3189@kroah.com> From: Gao Xiang Message-ID: <1d1fd688-0cb5-cbac-9213-f56f7e356bca@huawei.com> Date: Thu, 22 Nov 2018 18:56:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20181122102230.GF3189@kroah.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.151.23.176] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Greg, On 2018/11/22 18:22, Greg Kroah-Hartman wrote: > Please document this memory barrier. It does not make much sense to > me... Because we need to make the other observers noticing the latest values modified in this locking period before unfreezing the whole workgroup, one way is to use a memory barrier and the other way is to use ACQUIRE and RELEASE. we selected the first one. Hmmm...ok, I will add a simple message to explain this, but I think that is plain enough for a lock... Thanks, Gao Xiang > > thanks, > > greg k-h