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=-0.2 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,FREEMAIL_REPLYTO_END_DIGIT, 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 06E43C00449 for ; Wed, 3 Oct 2018 07:05:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9021B213A2 for ; Wed, 3 Oct 2018 07:05:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9021B213A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.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 S1727109AbeJCNwf (ORCPT ); Wed, 3 Oct 2018 09:52:35 -0400 Received: from mga04.intel.com ([192.55.52.120]:3810 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726521AbeJCNwf (ORCPT ); Wed, 3 Oct 2018 09:52:35 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Oct 2018 00:05:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,334,1534834800"; d="scan'208";a="262431002" Received: from linux.intel.com ([10.54.29.200]) by orsmga005.jf.intel.com with ESMTP; 03 Oct 2018 00:05:30 -0700 Received: from abityuts-desk.fi.intel.com (abityuts-desk.fi.intel.com [10.237.68.39]) by linux.intel.com (Postfix) with ESMTP id 7F350580268; Wed, 3 Oct 2018 00:05:26 -0700 (PDT) Message-ID: <1538550325.14984.108.camel@gmail.com> Subject: Re: [PATCH] block: BFQ default for single queue devices From: Artem Bityutskiy Reply-To: dedekind1@gmail.com To: Paolo Valente , Jens Axboe Cc: Linus Walleij , linux-block , linux-mmc , linux-mtd@lists.infradead.org, Pavel Machek , Ulf Hansson , Richard Weinberger , Adrian Hunter , Jan Kara , Andreas Herrmann , Mel Gorman , Chunyan Zhang , linux-kernel , 'Paolo Valente' via bfq-iosched , Oleksandr Natalenko , Mark Brown Date: Wed, 03 Oct 2018 10:05:25 +0300 In-Reply-To: References: <20181002124329.21248-1-linus.walleij@linaro.org> <05fdbe23-ec01-895f-e67e-abff85c1ece2@kernel.dk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 (3.26.6-1.fc27) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-10-03 at 08:29 +0200, Paolo Valente wrote: > So, I do understand your need for conservativeness, but, after so much > evidence on single-queue devices, and so many years! :), what's the > point in keeping Linux worse for virtually everybody, by default? Sounds like what we just need a mechanism for the device (ubi block in this case) to select the I/O scheduler. I doubt enhancing the default scheduler selection logic in 'elevator.c' is the right answer. Just give the driver authority to override the defaults.