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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 10241C49ED7 for ; Thu, 19 Sep 2019 17:48:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E167F21BE5 for ; Thu, 19 Sep 2019 17:48:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="K8VVX19o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390297AbfISRst (ORCPT ); Thu, 19 Sep 2019 13:48:49 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:45542 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389875AbfISRss (ORCPT ); Thu, 19 Sep 2019 13:48:48 -0400 Received: by mail-io1-f67.google.com with SMTP id f12so9688885iog.12 for ; Thu, 19 Sep 2019 10:48:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=iC74FDHxst+tccsETTle3rR7zrtvRzSQgS7jIMs0SKk=; b=K8VVX19of7Fa2rcJGX5psG2u0F8xohovO/uB9f7qab3ZbxMpQjp9ogZYxXLsqVwxIB ms8OBL23MhzE73wvlkkcPYwkUlJL23U60wI5zokEp7lm05hI8bLb2SCa9MprtYsivXQU /4iAO8ae1zTwhOP2zmfXSNnwIAnfIOVpWqh6fPbCBjmqA9NAvVTRGTQFeJNQD4aDqhqx Vwp6ZP8JV+zXbRDprNXGP3bJd/Hw8DE/xXZAV5PWqfXbkGbqa51iZvhHadJF95OyAh83 IuCh4WUH+yrE1dR3qYviM7yQ/rMiyQz5l8mmT1J4+/GrFp4Usde7MEvQffREy5oioTKs DuUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=iC74FDHxst+tccsETTle3rR7zrtvRzSQgS7jIMs0SKk=; b=hJ/G3TFEPZxNsPMgG/yJGDi+kh9pJCJw/Rqko+nnwaB+yij74GUR0WIhGF7HaKDjZA tnDKGVfNu+GnrOXfXjoAqpUrJtKtyd5M9o75TXhPb/CSdcBgmvXDG6R8/vkxirq9qSuZ LauMWagoXyt9S2RKNU8nFxADZt+usqo0PjxeGvdNdOol6pbHd16zBsHlAAEbp/R7VFKt 0iaNpIQsXmWk53T48Bvmff/roBdwtcwX3ecJPbRqC8voAPTG+7IkVd0cyWarppUBsVjy kxtojCCRnRFw0sz3Iofl+musvtP0ABCrtKUaVLILHIJH4NUk2zHoO9L+eZxfZwObRQ0q Xsmw== X-Gm-Message-State: APjAAAVldm8SkPSu11K8FFKnluLkeac9KwGareA0B07BGEEHAKnwqPGV eKYmOp/6iNnMLM5Ab8K7kIyOtg== X-Google-Smtp-Source: APXvYqxkQMcVy/dqy9FUS/DErap8Adkqyvgw4K9DQx7F4UW0e2KGzwQyJFNQqYvQ1UleK5CHZEj8WQ== X-Received: by 2002:a5e:851a:: with SMTP id i26mr13106869ioj.304.1568915327323; Thu, 19 Sep 2019 10:48:47 -0700 (PDT) Received: from [192.168.1.50] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id f8sm7883134ioo.27.2019.09.19.10.48.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Sep 2019 10:48:46 -0700 (PDT) Subject: Re: [RFC PATCH 0/2] blk-mq I/O scheduling fixes To: Hannes Reinecke Cc: linux-scsi@vger.kernel.org, "Martin K. Petersen" , James Bottomley , Christoph Hellwig , linux-block@vger.kernel.org, Hans Holmberg , Damien Le Moal References: <20190919094547.67194-1-hare@suse.de> From: Jens Axboe Message-ID: <1bde2781-9958-9bf1-2d89-8c4f9f0d8cba@kernel.dk> Date: Thu, 19 Sep 2019 11:48:45 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190919094547.67194-1-hare@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 9/19/19 3:45 AM, Hannes Reinecke wrote: > Hi all, > > Damien pointed out that there are some areas in the blk-mq I/O > scheduling algorithm which have a distinct legacy feel to it, > and prohibit multiqueue I/O schedulers from working properly. > These two patches should clear up this situation, but as it's > not quite clear what the original intention of the code was > I'll be posting them as an RFC. > > So as usual, comments and reviews are welcome. > > Hannes Reinecke (2): > blk-mq: fixup request re-insert in blk_mq_try_issue_list_directly() > blk-mq: always call into the scheduler in blk_mq_make_request() > > block/blk-mq.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) Not quite sure what to do with this... Did you test them at all? One is obviously broken and would crash the kernel, the other is/was a performance optimization done not that long ago. Just going to ignore this series for now. -- Jens Axboe