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 4F44CC636CC for ; Wed, 15 Feb 2023 06:47:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229632AbjBOGr3 (ORCPT ); Wed, 15 Feb 2023 01:47:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229551AbjBOGr2 (ORCPT ); Wed, 15 Feb 2023 01:47:28 -0500 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5497F2A6E0 for ; Tue, 14 Feb 2023 22:47:27 -0800 (PST) Received: by verein.lst.de (Postfix, from userid 2407) id 0D78667373; Wed, 15 Feb 2023 07:47:24 +0100 (CET) Date: Wed, 15 Feb 2023 07:47:23 +0100 From: Christoph Hellwig To: Pankaj Raghav Cc: Ming Lei , axboe@kernel.dk, hch@lst.de, mcgrof@kernel.org, gost.dev@samsung.com, linux-block@vger.kernel.org Subject: Re: [PATCH 0/1] improve brd performance with blk-mq Message-ID: <20230215064723.GA30472@lst.de> References: <20230203103005.31290-1-p.raghav@samsung.com> <6035da22-5667-93d5-fe00-62b988425cb5@samsung.com> <95506a88-c89c-0f41-3ab4-eb5741410c02@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <95506a88-c89c-0f41-3ab4-eb5741410c02@samsung.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Feb 14, 2023 at 08:18:54PM +0530, Pankaj Raghav wrote: > Should we add a module parameter to switch between bio and blk-mq back-end > in brd, similar to null_blk? The default option would be bio to avoid > regression on existing workloads. No. Duplicate code paths are alaways a bad idea. Please drill in further what causes the differences.