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 6B1AFD68BCD for ; Fri, 15 Nov 2024 16:54:05 +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=veMkJq9q+kGKKZj9Qv5GNLbU/IHDs7X+vABTAhrJdco=; b=o/1lk/0aPfG60FD7p0hOLmhMTd 757t+0xgZLfiBiAQHpLovyGF09IdjF9fJl4OMmTKY3KLY6plw3h7iGO/Y99Vb9Ksf/67CjDUPIsZV tHBdQRRHhhkjesU1+VKIDVWPLjyRPN1eubQjWojx4xktVsi9stEUWc1dO4CB+8tYeWLwGQWfl49MU 13lkePsbmnmvJ43PxIR2U5s06tYiFlvuOy//wn0woH4WaYJbslzlN/MkxaVYr7K83bDUCQjbm97PO dpqWbBiDtlBYetzOGRoAeoy0F83imaGgXuXXpjkT531G54m3Dkv+PseRLdmaomChIrVNAMWr2uoOZ x3Uacp6g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tBza7-00000003Rjo-08tE; Fri, 15 Nov 2024 16:54:03 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tBza4-00000003Ri9-2p4p for linux-nvme@lists.infradead.org; Fri, 15 Nov 2024 16:54:02 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 8B41D67373; Fri, 15 Nov 2024 17:53:49 +0100 (CET) Date: Fri, 15 Nov 2024 17:53:48 +0100 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , Dave Chinner , Pierre Labat , Kanchan Joshi , Keith Busch , "linux-block@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "linux-scsi@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "io-uring@vger.kernel.org" , "axboe@kernel.dk" , "martin.petersen@oracle.com" , "asml.silence@gmail.com" , "javier.gonz@samsung.com" Subject: Re: [EXT] Re: [PATCHv11 0/9] write hints with nvme fdp and scsi streams Message-ID: <20241115165348.GA22628@lst.de> References: <20241111102914.GA27870@lst.de> <7a2f6231-bb35-4438-ba50-3f9c4cc9789a@samsung.com> <20241112133439.GA4164@lst.de> <20241113044736.GA20212@lst.de> <20241114060710.GA11169@lst.de> 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-20241115_085400_855751_875C5BA2 X-CRM114-Status: GOOD ( 17.06 ) 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, Nov 15, 2024 at 09:28:05AM -0700, Keith Busch wrote: > SSDs operates that way. FDP just reports more stuff because that's what > people kept asking for. But it doesn't require you fundamentally change > how you acces it. You've singled out FDP to force a sequential write > requirement that that requires unique support from every filesystem > despite the feature not needing that. No I haven't. If you think so you are fundamentally misunderstanding what I'm saying. > We have demonstrated 40% reduction in write amplifcation from doing the > most simplist possible thing that doesn't require any filesystem or > kernel-user ABI changes at all. You might think that's not significant > enough to let people realize those gains without more invasive block > stack changes, but you may not buying NAND in bulk if that's the case. And as iterared multiple times you are doing that by bypassing the file system layer in a forceful way that breaks all abstractions and makes your feature unavailabe for file systems. I've also thrown your a nugget by first explaining and then even writing protype code to show how you get what you want while using the proper abstractions. But instead of a picking up on that you just whine like this. Either spend a little bit of effort to actually get the interface right or just shut up.