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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 DA6BDC5DF63 for ; Wed, 6 Nov 2019 15:01:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B707C2178F for ; Wed, 6 Nov 2019 15:01:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728712AbfKFPBH (ORCPT ); Wed, 6 Nov 2019 10:01:07 -0500 Received: from mx2.suse.de ([195.135.220.15]:37268 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727958AbfKFPBG (ORCPT ); Wed, 6 Nov 2019 10:01:06 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6B0BCB55B; Wed, 6 Nov 2019 15:01:05 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 2B0731E4353; Wed, 6 Nov 2019 16:01:05 +0100 (CET) Date: Wed, 6 Nov 2019 16:01:05 +0100 From: Jan Kara To: Jens Axboe Cc: Jan Kara , linux-block@vger.kernel.org, mgorman@suse.de, hare@suse.de Subject: Re: elevator= kernel argument for recent kernels Message-ID: <20191106150105.GK16085@quack2.suse.cz> References: <20191106105340.GE16085@quack2.suse.cz> <1a0539a7-75c2-1ad6-aa5c-bf07a92e1eb3@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1a0539a7-75c2-1ad6-aa5c-bf07a92e1eb3@kernel.dk> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed 06-11-19 07:15:35, Jens Axboe wrote: > On 11/6/19 3:53 AM, Jan Kara wrote: > > Hello, > > > > with transition to blk-mq, the elevator= kernel argument was removed. I > > understand the reasons for its removal but still I think this may come as a > > surprise to some users since that argument has been there for ages and > > although distributions generally transition to setting appropriate elevator > > by udev rules, there are still people that use that argument with older > > kernels and there are quite a few advices on the Internet to use it. So > > shouldn't we at least warn loudly if someone uses elevator= argument on > > kernels that don't support it and redirect people to sysfs? Something like > > the attached patch? What do people think? > > I'm fine with that, my objects have always been centered around trying > to make the parameter work. A warning makes sense to point people in > the right direction. I'll add this for 5.5. Thanks! Honza -- Jan Kara SUSE Labs, CR