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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 E3A4EC433DF for ; Wed, 24 Jun 2020 02:54:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C622820874 for ; Wed, 24 Jun 2020 02:54:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388354AbgFXCyX (ORCPT ); Tue, 23 Jun 2020 22:54:23 -0400 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:35055 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387985AbgFXCyX (ORCPT ); Tue, 23 Jun 2020 22:54:23 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07425;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0U0Z11ni_1592967259; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0U0Z11ni_1592967259) by smtp.aliyun-inc.com(127.0.0.1); Wed, 24 Jun 2020 10:54:19 +0800 Date: Wed, 24 Jun 2020 10:54:19 +0800 From: Baolin Wang To: Keith Busch Cc: Sagi Grimberg , axboe@fb.com, hch@lst.de, baolin.wang7@gmail.com, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] nvme: Add Arbitration Burst support Message-ID: <20200624025419.GA63524@VM20190228-100.tbsite.net> Reply-To: Baolin Wang References: <20200623144014.GB1288900@dhcp-10-100-145-180.wdl.wdc.com> <38482b1b-b1c7-bb41-b086-6ce00f6a9d1d@grimberg.me> <20200623180108.GA1291100@dhcp-10-100-145-180.wdl.wdc.com> <20200624013408.GA40094@VM20190228-100.tbsite.net> <20200624025135.GA1291930@dhcp-10-100-145-180.wdl.wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200624025135.GA1291930@dhcp-10-100-145-180.wdl.wdc.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 23, 2020 at 07:51:35PM -0700, Keith Busch wrote: > On Wed, Jun 24, 2020 at 09:34:08AM +0800, Baolin Wang wrote: > > OK, I understaood your concern. Now we will select the RR arbitration as default > > in nvme_enable_ctrl(), but for some cases, we will not set the arbitration burst > > values from userspace, and we still want to use the defaut arbitration burst that > > recommended by the controller, taking into consideration any latency requirements. > > > > So I'd like to add a parameter to decide if we can use the default arbitration > > burst like below, how do yo think? Thanks. > > I wouldn't call this the 'default' arbitration since it usually is not > the default. This is the 'recommended' arbitration value. OK. Change to rename the variable as: static bool use_recommended_arb; > > > static bool use_default_arb; > > module_param(use_default_arb, bool, 0444); > > MODULE_PARM_DESC(use_default_arb, "use default arbitration burst that > > recommended by the controller"); > > "use controller's recommended arbitration burst" Sure. Thanks.