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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 221CCC4332F for ; Fri, 18 Nov 2022 10:47:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241643AbiKRKro (ORCPT ); Fri, 18 Nov 2022 05:47:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241569AbiKRKri (ORCPT ); Fri, 18 Nov 2022 05:47:38 -0500 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F821326F3; Fri, 18 Nov 2022 02:47:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668768457; x=1700304457; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=LZLmUknSd1/aIfUwWzdJ0VDIOATUMOVkhWKDwKyeJuA=; b=V++wbEwMv4nIeYmHAwlmzWVRMNpiWXZgD1SboDeEFJSl/Mv6ttfwVqDM 7k1xNTjoMTGk2p8pqOL5UCuigIUefihfH0ux/UFksJdh6+m1ms/RfGX9R 8IDTM3ueTH7UgxKXwbYEzaGVSA02/ZxyeNUOBbzSt3pxW97FUsbTjZk/A /n72S3Jfev2hkiw1gIpb5FTRGnZKWRriDWBjrF/t90cw1Yb659GmZaf/x ibHtdzPC1BfIy7OKz7hwcc5mKqlIG9fGnUxKcwXA7HV0cWkkP9cRHBZl9 DlthzfJWOUaS5ubZdJuz8y/BOyqNYZ5IYrUKv4XLqHJ8VIZXU91jkYxHS A==; X-IronPort-AV: E=McAfee;i="6500,9779,10534"; a="293500091" X-IronPort-AV: E=Sophos;i="5.96,174,1665471600"; d="scan'208";a="293500091" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2022 02:47:37 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10534"; a="782605566" X-IronPort-AV: E=Sophos;i="5.96,174,1665471600"; d="scan'208";a="782605566" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.252.61.138]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2022 02:47:34 -0800 Message-ID: Date: Fri, 18 Nov 2022 12:47:29 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.5.0 Subject: Re: [PATCH 0/3] mmc: Improve block layer requeueing behavior Content-Language: en-US To: =?UTF-8?Q?Christian_L=c3=b6hle?= , "axboe@kernel.dk" , "ulf.hansson@linaro.org" , "linux-mmc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , Christoph Hellwig Cc: Avri Altman , "vincent.whitchurch@axis.com" References: From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26/10/22 10:30, Christian Löhle wrote: > Mmcblk relies on block layer requeueing to fulfill some requests under > certain conditions. Improve the handling to get nicely ordered requests. > > Using the terms a bit loosely to get a point across: > Current behavior for 512 blksz and max_blk_count = 1 the scenario would > be as follows: > > - request for page 0 lba 0 to 7 > - request for page 1 lba 8 to 15 > - request for page 2 lba 16 to 23 > - request for page 3 lba 24 to 31 > > mmcblk modifies data->blocks = 1 for each and requeues, > this leads to: > > Access lba 0 > Access lba 8 > Access lba 16 > Access lba 24 > Access lba 1 (1. Requeue for page 0) > Access lba 9 (1. Requeue for page 1) > Access lba 17 (1. Requeue for page 2) > Access lba 25 (1. Requeue for page 3) > Access lba 2 (2. Requeue for page 0) > ... > > Of course we would rather have lbas consecutive. Does anyone know why the block layer does not support (max_hw_sectors << 9) < PAGE_SIZE ?