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 BCC6DC433F5 for ; Fri, 4 Feb 2022 16:01:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234036AbiBDQBr (ORCPT ); Fri, 4 Feb 2022 11:01:47 -0500 Received: from verein.lst.de ([213.95.11.211]:41815 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231664AbiBDQBq (ORCPT ); Fri, 4 Feb 2022 11:01:46 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 9C75E68AA6; Fri, 4 Feb 2022 17:01:40 +0100 (CET) Date: Fri, 4 Feb 2022 17:01:40 +0100 From: Christoph Hellwig To: Hannes Reinecke Cc: Chaitanya Kulkarni , Javier =?iso-8859-1?Q?Gonz=E1lez?= , Damien Le Moal , Luis Chamberlain , Mikulas Patocka , "linux-block@vger.kernel.org" , Keith Busch , Adam Manzanares , "linux-scsi@vger.kernel.org" , "dm-devel@redhat.com" , "linux-nvme@lists.infradead.org" , linux-fsdevel , Jens Axboe , "msnitzer@redhat.com >> msnitzer@redhat.com" , Bart Van Assche , "martin.petersen@oracle.com >> Martin K. Petersen" , "roland@purestorage.com" , Christoph Hellwig , "Frederick.Knight@netapp.com" , "zach.brown@ni.com" , "osandov@fb.com" , "lsf-pc@lists.linux-foundation.org" , "djwong@kernel.org" , "josef@toxicpanda.com" , "clm@fb.com" , "dsterba@suse.com" , "tytso@mit.edu" , "jack@suse.com" , Kanchan Joshi Subject: Re: [RFC PATCH 3/3] nvme: add the "debug" host driver Message-ID: <20220204160140.GA6817@lst.de> References: <20220203153843.szbd4n65ru4fx5hx@garbanzo> <20220203165238.GA142129@dhcp-10-100-145-180.wdc.com> <20220203195155.GB249665@bgt-140510-bm01> <863d85e3-9a93-4d8c-cf04-88090eb4cc02@nvidia.com> <2bbed027-b9a1-e5db-3a3d-90c40af49e09@opensource.wdc.com> <9d5d0b50-2936-eac3-12d3-a309389e03bf@nvidia.com> <20220204082445.hczdiy2uhxfi3x2g@ArmHalley.local> <4d5410a5-93c3-d73c-6aeb-2c1c7f940963@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Feb 04, 2022 at 03:15:02PM +0100, Hannes Reinecke wrote: >> ZNS kernel code testing is also done on QEMU, I've also fixed >> bugs in the ZNS kernel code which are discovered on QEMU and I've not >> seen any issues with that. Given that simple copy feature is way smaller >> than ZNS it will less likely to suffer from slowness and etc (listed >> above) in QEMU. >> >> my point is if we allow one, we will be opening floodgates and we need >> to be careful not to bloat the code unless it is _absolutely >> necessary_ which I don't think it is based on the simple copy >> specification. >> > > I do have a slightly different view on the nvme target code; it should > provide the necessary means to test the nvme host code. > And simple copy is on of these features, especially as it will operate as > an exploiter of the new functionality. Well, in general I'd like to have every useful feature supported in nvmet, because it serves both testing and production. If a feature isn't all that useful (and there are lots of those in nvme these days) we don't need to support in nvmet, but probably neither in the host code. 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 [170.10.133.124]) (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 42B80C433EF for ; Fri, 4 Feb 2022 16:08:55 +0000 (UTC) Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-490-_q3BLLtEMuiPiytuIhzJeg-1; Fri, 04 Feb 2022 11:08:50 -0500 X-MC-Unique: _q3BLLtEMuiPiytuIhzJeg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 534E45F9C5; Fri, 4 Feb 2022 16:08:45 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AE58F753E4; Fri, 4 Feb 2022 16:08:42 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 607671809CB8; Fri, 4 Feb 2022 16:08:37 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 214G1mlT009807 for ; Fri, 4 Feb 2022 11:01:49 -0500 Received: by smtp.corp.redhat.com (Postfix) id D19B6492D56; Fri, 4 Feb 2022 16:01:48 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast10.extmail.prod.ext.rdu2.redhat.com [10.11.55.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CCABE492D4A for ; Fri, 4 Feb 2022 16:01:48 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (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 B49BC1C0783C for ; Fri, 4 Feb 2022 16:01:48 +0000 (UTC) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-16-zMNYW1ugNeeqqfsqwJm5Rw-1; Fri, 04 Feb 2022 11:01:46 -0500 X-MC-Unique: zMNYW1ugNeeqqfsqwJm5Rw-1 Received: by verein.lst.de (Postfix, from userid 2407) id 9C75E68AA6; Fri, 4 Feb 2022 17:01:40 +0100 (CET) Date: Fri, 4 Feb 2022 17:01:40 +0100 From: Christoph Hellwig To: Hannes Reinecke Message-ID: <20220204160140.GA6817@lst.de> References: <20220203153843.szbd4n65ru4fx5hx@garbanzo> <20220203165238.GA142129@dhcp-10-100-145-180.wdc.com> <20220203195155.GB249665@bgt-140510-bm01> <863d85e3-9a93-4d8c-cf04-88090eb4cc02@nvidia.com> <2bbed027-b9a1-e5db-3a3d-90c40af49e09@opensource.wdc.com> <9d5d0b50-2936-eac3-12d3-a309389e03bf@nvidia.com> <20220204082445.hczdiy2uhxfi3x2g@ArmHalley.local> <4d5410a5-93c3-d73c-6aeb-2c1c7f940963@nvidia.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) 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 X-loop: dm-devel@redhat.com Cc: "djwong@kernel.org" , "linux-nvme@lists.infradead.org" , "clm@fb.com" , "dm-devel@redhat.com" , Adam Manzanares , "osandov@fb.com" , "msnitzer@redhat.com >> msnitzer@redhat.com" , Bart Van Assche , "linux-scsi@vger.kernel.org" , Damien Le Moal , Christoph Hellwig , "roland@purestorage.com" , "zach.brown@ni.com" , "dsterba@suse.com" , Chaitanya Kulkarni , Javier =?iso-8859-1?Q?Gonz=E1lez?= , "josef@toxicpanda.com" , "linux-block@vger.kernel.org" , Mikulas Patocka , Keith Busch , "Frederick.Knight@netapp.com" , Jens Axboe , "tytso@mit.edu" , Kanchan Joshi , "martin.petersen@oracle.com >> Martin K. Petersen" , Luis Chamberlain , "jack@suse.com" , linux-fsdevel , "lsf-pc@lists.linux-foundation.org" Subject: Re: [dm-devel] [RFC PATCH 3/3] nvme: add the "debug" host driver X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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 Fri, Feb 04, 2022 at 03:15:02PM +0100, Hannes Reinecke wrote: >> ZNS kernel code testing is also done on QEMU, I've also fixed >> bugs in the ZNS kernel code which are discovered on QEMU and I've not >> seen any issues with that. Given that simple copy feature is way smaller >> than ZNS it will less likely to suffer from slowness and etc (listed >> above) in QEMU. >> >> my point is if we allow one, we will be opening floodgates and we need >> to be careful not to bloat the code unless it is _absolutely >> necessary_ which I don't think it is based on the simple copy >> specification. >> > > I do have a slightly different view on the nvme target code; it should > provide the necessary means to test the nvme host code. > And simple copy is on of these features, especially as it will operate as > an exploiter of the new functionality. Well, in general I'd like to have every useful feature supported in nvmet, because it serves both testing and production. If a feature isn't all that useful (and there are lots of those in nvme these days) we don't need to support in nvmet, but probably neither in the host code. -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel