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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2F909C433F5 for ; Fri, 4 Feb 2022 16:03:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XjiTz7mXDOHiGAQbahHjKneaooqlEcoZjPNDRyJUiI4=; b=wAOSsBoyXcaJE24t+nIgV7ZSAF ezAon6Vd90etb7FuXPb/Tnp39/TKbuUAsOsA6WZ2MtoFped7pZqIv3wNF/An8D5rhzA3GTbP+H2dn /+SizHlZ61dtad3cB/wOMw7f3Wk5tqOiOVb2PC3MzpGoI74RTgJg3Dpyz6INUHAPrsZjR2XYlliW4 hsZpZkTCxceXcX9RwFuYrLe7rMJx6H6e0G3Mk0KKiCrTuwv1EcWU0X8W47hmolgU2wxwj65YAeDkN XKYI9CKBvBd3uhMKZcdKM8jMJC8ntNkz6pu0BlGZi92AeyoDeE4Omnj49etb1+dMvGTqxhH/3Byn9 6LqkFV+A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nG13J-004sY8-9n; Fri, 04 Feb 2022 16:03:13 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nG11u-004s1h-CP for linux-nvme@lists.infradead.org; Fri, 04 Feb 2022 16:01:48 +0000 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) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220204_080146_591310_2F88B6F0 X-CRM114-Status: GOOD ( 19.73 ) X-Mailman-Approved-At: Fri, 04 Feb 2022 08:03:11 -0800 X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.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.