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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 8BB71C433E0 for ; Tue, 11 Aug 2020 03:13:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 700F82075D for ; Tue, 11 Aug 2020 03:13:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727777AbgHKDNW (ORCPT ); Mon, 10 Aug 2020 23:13:22 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:9798 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726981AbgHKDNW (ORCPT ); Mon, 10 Aug 2020 23:13:22 -0400 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 7E13A863C7704E13A4B4; Tue, 11 Aug 2020 11:13:20 +0800 (CST) Received: from [10.169.42.93] (10.169.42.93) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.487.0; Tue, 11 Aug 2020 11:13:14 +0800 Subject: Re: [PATCH v2 0/3] reduce quiesce time for lots of name spaces To: Ming Lei CC: , , , , , References: <20200807090559.29582-1-lengchao@huawei.com> <20200807134932.GA2122627@T590> <61a78a78-73aa-1c67-1e8c-eae8f7c3a4e0@huawei.com> <20200810031547.GB2202641@T590> From: Chao Leng Message-ID: <6dc6bb01-5bfd-bf13-f53a-1bc75a6b3991@huawei.com> Date: Tue, 11 Aug 2020 11:13:14 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200810031547.GB2202641@T590> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.169.42.93] X-CFilter-Loop: Reflected Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2020/8/10 11:15, Ming Lei wrote: >> About using per_cpu to replace SRCU, I suggest separate discussion. >> Can you show the patch? This will make it easier to discuss. > https://lore.kernel.org/linux-block/20200728134938.1505467-1-ming.lei@redhat.com/ Directly replace SRCU with percpu_ref, is not safe. This may make quiesce queue wait extra time, in extreme scenario, maybe wait for ever.