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 86845C27C55 for ; Mon, 10 Jun 2024 14:52:23 +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=dSQwKfpYeYJ7SKay4pPkgwBIm1t/rT6H9fUbzG745dY=; b=45Tibu//D0gYac8RAd3nkgTbeI GbKpBdpZGAMbyCGM4Iu9mtf5x/lS4dscSdt6nx7fYAKgDzMUQx9gxnUD0A4oUGwWeF+e/jZgKu0ZV lXTTtzv+KmOczIqE275czBXB/gIXVe8di2OcMo59buqYHWFG0y/RlVGnH7c3KVLqtwnhP671dJmWs MHYyNgrDMYszhOprTBauvIlMvMlwIBOqNiBemxmncnPWrgXTwSm6TXqTbKKf1DEY472pJ28+nSJs8 KwHvv59aJk95rPFqONOiCkIQimbV5p9TlhQOcOGLEwLdi+UESRK08ynLDSOV0TVoqtVPGfpPh3NRB ZOxA+8HA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sGgNh-00000005W7s-0SI3; Mon, 10 Jun 2024 14:52:21 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sGgNd-00000005W74-2rkU for linux-nvme@lists.infradead.org; Mon, 10 Jun 2024 14:52:19 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 1697260A05; Mon, 10 Jun 2024 14:52:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F3FDC2BBFC; Mon, 10 Jun 2024 14:52:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718031135; bh=2S4HydQ/UnLsPZpFEQmcFHWEoIdTKPvcrhWMPLZhvKg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OUt+voxdNlPyWqI7hXgf1+AHJOeu86NZblxShOj1rR735ORJ9hJ2I2tACP18PWKLs 8PcWLFdUCIc12zJZppIxScMcOArxMFIzZg8GONfzEgNnPZt/WCmBIldfo0Gxz0Ns/v olzuxVe8jjxZYjYO7L79T0tQbgZZG+5GYANqrefIYaedT/DBrcGD9ikr39bg+Aev5Z MBsAxV8RoMbPS9sZZOwPn5xcJpY8pJyVmtoFHVPr2IgFKzR1edoQWETZi0n5AJEb69 hrR7hF9KLu6/ACY/c6rst/m7qv/qq85LWrfE19wl9Ldqg1E4W/LJbZ6bDfOpqRc5LS VvRr73Y11Rq8g== Date: Mon, 10 Jun 2024 08:52:12 -0600 From: Keith Busch To: Christoph Hellwig Cc: "Martin K. Petersen" , Kanchan Joshi , axboe@kernel.dk, sagi@grimberg.me, linux-nvme@lists.infradead.org, javier.gonz@samsung.com, bvanassche@acm.org, gost.dev@samsung.com, Hui Qi , Nitesh Shetty Subject: Re: [PATCH v2] nvme: enable FDP support Message-ID: References: <20240528150233.55562-1-joshi.k@samsung.com> <20240608051740.GA24010@lst.de> <5e686875-21de-869d-4b19-bdd9e272d690@samsung.com> <20240610115541.GB19495@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240610115541.GB19495@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240610_075217_887120_BC1ADF4B X-CRM114-Status: GOOD ( 19.38 ) 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 Mon, Jun 10, 2024 at 01:55:41PM +0200, Christoph Hellwig wrote: > On Mon, Jun 10, 2024 at 07:27:16AM -0400, Martin K. Petersen wrote: > > > And TP 4146 author list shows 10 companies. Perhaps good enough for > > > diverse opinions on how to go about things before settling down. > > > > I think FDP and SCSI streams are less than ideal. 10+ years and the > > standards bodies still haven't been able to produce an approach that > > makes sense in the context of a general purpose operating system. > > The SCSI temperature hints are I think exactly what we want. The fact > that they had to be shoe horned in in a weird to claim to be streams > is a little awkward, but sometimes that's need to get things done. I feel a bit out of the loop here, I'm not sure what the concern is. I agree the FDP setup is complicated, but none of that is taken on by the driver. It just discovers the capabilities and maps an arbitrary software "hint" to an arbitrary device "hint". It's up to the application to use those optimally; the driver just performs the requested mapping. Is it because the names of those hints indicate data lifetime? These are just arbitrary numbers used by applications to separate placement. If they were called HINT_A, HINT_B, HINT_C, would that make this ok?