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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 D2F10C433E0 for ; Tue, 22 Dec 2020 13:33:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA8B723103 for ; Tue, 22 Dec 2020 13:33:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727416AbgLVNdn (ORCPT ); Tue, 22 Dec 2020 08:33:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727329AbgLVNdm (ORCPT ); Tue, 22 Dec 2020 08:33:42 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D85B9C06179C; Tue, 22 Dec 2020 05:33:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=L72h3sjEObPKtskr0qgLJjQgQiwOWQdgosDwtPfonDE=; b=jBaNN9MYdKMfzwMcvvDfw/KK6s +0Ey2ZfmzkxF/eweGQjUgC8k8a4tOJj3JrSzTapbKYK4foMg7KIXO0qa4WgaMBBOKrPj6TFYP1GKe sfFZjzxPsYevDI98Hr7rsJAvWE5Anor7VTv8auhSQ1pHuVfFP7E83W0rICTVHQ+JcrrEhAGuhXzj0 QfaWq/5NquWlJk4zx+Yu3fuq5SqUn666FBE+yzT20MrwiUePW4RMQezaurmQ/BNsYXGgPJS3G/6WP v4o/V1Hjlk4k0eP1ylBbDrrzn7+7Y9JMlcz/xb3awLry9RiwxxC02J/t9M5qgnDmZrTXE9CuTsW5b AO4F+cTw==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1krhmQ-0001SZ-29; Tue, 22 Dec 2020 13:32:46 +0000 Date: Tue, 22 Dec 2020 13:32:46 +0000 From: Christoph Hellwig To: Palmer Dabbelt Cc: josef@toxicpanda.com, bvanassche@acm.org, Christoph Hellwig , snitzer@redhat.com, corbet@lwn.net, kernel-team@android.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, song@kernel.org, dm-devel@redhat.com, linux-kselftest@vger.kernel.org, shuah@kernel.org, agk@redhat.com, michael.christie@oracle.com Subject: Re: [dm-devel] [PATCH v1 0/5] dm: dm-user: New target that proxies BIOs to userspace Message-ID: <20201222133246.GA5099@infradead.org> References: <30d39293-80a4-9ef5-92bb-6b6dec464be3@toxicpanda.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 14, 2020 at 07:00:57PM -0800, Palmer Dabbelt wrote: > I haven't gotten a whole lot of feedback, so I'm inclined to at least have some > reasonable performance numbers before bothering with a v2. FYI, my other main worry beside duplicating nbd is that device mapper really is a stacked interface that sits on top of other block device. Turning this into something else that just pipes data to userspace seems very strange.