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 37D39C433F5 for ; Thu, 10 Feb 2022 05:43:41 +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=JU18tfsvbDrRI0FvAgG69HuDEl7Yion08wCqeicqQk4=; b=mpbE+Xac0FUJK8tsXWDOuS8V4P k52sCneSNgv1E/3L4QboPRZ9kY5lxHe5v7/9ZKP+bKuwKOQxSTSEJYsYOUgzf6UC7al3SC4NmyzR7 WpYwu9K8jAJNYg0RohEXb41hh2Et5qggINNQPKpZkLWjHuXzWl0pBp0J/I8aPeMex0BQBkZiS9ZVX 1LzlpHuJw+Hx5M4BwM2jM+d4q6r3TNcPGwN0isbz2bxGzXRfQnGO9cpr5alM91a7rOjvOKLM2xHT1 aXwmJjd+9jO0NgOZCVidMluC0IB+4d+E5EFNCIyd0evd94L+fW1jWw6laUDXZ1e6i0657ydwsMrqJ XEAVjhDw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nI2Ex-002e9H-0S; Thu, 10 Feb 2022 05:43:35 +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 1nI2Et-002e6s-Kb for linux-nvme@lists.infradead.org; Thu, 10 Feb 2022 05:43:33 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 51EED67373; Thu, 10 Feb 2022 06:43:23 +0100 (CET) Date: Thu, 10 Feb 2022 06:43:23 +0100 From: Christoph Hellwig To: John Meneghini Cc: Christoph Hellwig , Hannes Reinecke , Sagi Grimberg , Keith Busch , linux-nvme@lists.infradead.org Subject: Re: [PATCH] nvme-multipath: add an 'ana_groups_only' module option Message-ID: <20220210054323.GA3293@lst.de> References: <20220207100005.34404-1-hare@suse.de> <20220209080747.GA9851@lst.de> <56fb153a-ba0e-605b-e774-885c259965a6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56fb153a-ba0e-605b-e774-885c259965a6@redhat.com> 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-20220209_214331_863167_9DD02E4F X-CRM114-Status: GOOD ( 19.58 ) 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 Wed, Feb 09, 2022 at 09:52:45PM -0500, John Meneghini wrote: > I agree with Christoph. I don't see the point in supporting 65536 > namespaces across 49 ana groups or controllers. The problem here is: the > vendor is trying to turn NVMe into SCSI. I'm not saying we should not support it. We can trivially do that by using a vmalloc buffer. I don't think we should optimize for it, and we certainly should not break behaviour which I think this does. > > Moreover, I don't understand how implementing this as a MODULE_PARM is > supposed to work. If you configure this module parameter on it assumes all > NVMe-oF arrays connected to the host support RGO. What's really needed here > is some kind of protocol mechanism that will allow the host to dynamically > discovery if RGO is supported on a controller by controller basis. RGO support is mandatory and has been there since the first released ANA TP.