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 A1133C433EF for ; Tue, 29 Mar 2022 13:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231513AbiC2NgA (ORCPT ); Tue, 29 Mar 2022 09:36:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40440 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230330AbiC2NgA (ORCPT ); Tue, 29 Mar 2022 09:36:00 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92CA31F626; Tue, 29 Mar 2022 06:34:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=QUx/n+gFzgQBxeEXkD3spbgzkI2e56CAN02KOXZxJaI=; b=w/6iPI8bgV8iER5ysGWuY/CMSk //ZwXNSfxQHrlEPa+KReDK/eV4Tuvea2zSNR0YnvuRMs8GxZapw0YHioDbHhz9Onq25awDwLSDqJ+ lEdOUbDe+sp2++REdNRebbz62G/ce68GsALtf9JaNXLfRk+yLzbwijhBcUulz0sis/3wMjeA4ih3N vz+X2MhonFEimkZd+vU5Ycs2QWRJSWd2EZcWIRAob7+BiNTGmd2Srr/ioNcdn9bquvPSNVJGeuzA5 PEgQfZUjRRnCl1pztgGy3zNmbpRLdhf7ymN8JJTVwqO2vGVaOlw/WaOpKtv1yj6KIV6iElbvhyAN/ M0YD9TEQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZBzB-00CNM3-8O; Tue, 29 Mar 2022 13:34:13 +0000 Date: Tue, 29 Mar 2022 06:34:13 -0700 From: Christoph Hellwig To: Kirill Tkhai Cc: agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com, song@kernel.org, linux-kernel@vger.kernel.org, khorenko@virtuozzo.com, axboe@kernel.dk, linux-block@vger.kernel.org Subject: Re: [dm-devel] [PATCH 3/4] dm-qcow2: Introduce driver to create block devices over QCOW2 files Message-ID: References: <164846619932.251310.3668540533992131988.stgit@pro> <164846631540.251310.2398727490395218229.stgit@pro> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <164846631540.251310.2398727490395218229.stgit@pro> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Mar 28, 2022 at 02:18:35PM +0300, Kirill Tkhai wrote: > The driver is request based, since this allows to use blk-mq > merging of request. Driver splits requests itself, and every > request (i.e., qio) after splitting fits a single cluster. > (In some cases it is worth to create bigger splits, and this > is a subject of further optimizations). Nak, please don't do that. If you want finer grained processing use a bio based driver, not a request based one. This is just getting us into tons of problems. 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0710CC433EF for ; Tue, 29 Mar 2022 13:34:24 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-299-8CdfKn2wNYS-Y2h1SsUqXA-1; Tue, 29 Mar 2022 09:34:22 -0400 X-MC-Unique: 8CdfKn2wNYS-Y2h1SsUqXA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CA3A01C0690F; Tue, 29 Mar 2022 13:34:19 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id B84961400C2D; Tue, 29 Mar 2022 13:34:19 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 7C84E1940345; Tue, 29 Mar 2022 13:34:19 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 8DD5C1940342 for ; Tue, 29 Mar 2022 13:34:18 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 6353A54C6C6; Tue, 29 Mar 2022 13:34:18 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast02.extmail.prod.ext.rdu2.redhat.com [10.11.55.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5F0AC54C6C3 for ; Tue, 29 Mar 2022 13:34:18 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4514D80281D for ; Tue, 29 Mar 2022 13:34:18 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-615-PfYpg0_4PWuPpm-IxLccqA-1; Tue, 29 Mar 2022 09:34:16 -0400 X-MC-Unique: PfYpg0_4PWuPpm-IxLccqA-1 Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZBzB-00CNM3-8O; Tue, 29 Mar 2022 13:34:13 +0000 Date: Tue, 29 Mar 2022 06:34:13 -0700 From: Christoph Hellwig To: Kirill Tkhai Message-ID: References: <164846619932.251310.3668540533992131988.stgit@pro> <164846631540.251310.2398727490395218229.stgit@pro> MIME-Version: 1.0 In-Reply-To: <164846631540.251310.2398727490395218229.stgit@pro> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Subject: Re: [dm-devel] [PATCH 3/4] dm-qcow2: Introduce driver to create block devices over QCOW2 files X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: axboe@kernel.dk, snitzer@redhat.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, song@kernel.org, dm-devel@redhat.com, agk@redhat.com, khorenko@virtuozzo.com Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, Mar 28, 2022 at 02:18:35PM +0300, Kirill Tkhai wrote: > The driver is request based, since this allows to use blk-mq > merging of request. Driver splits requests itself, and every > request (i.e., qio) after splitting fits a single cluster. > (In some cases it is worth to create bigger splits, and this > is a subject of further optimizations). Nak, please don't do that. If you want finer grained processing use a bio based driver, not a request based one. This is just getting us into tons of problems. -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel