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 BEE5CC0218D for ; Wed, 29 Jan 2025 18:04:39 +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=6BhrRRn5LFueIgErKa4aNHztlX4iAnzv0g/GSKVTZQ0=; b=dRZRDD9uqf+apUmX7G2+0iitnL 3K2Bjl8lp470nk982bDkp+23r8FEndU2ssTot5/tqnWSPX3jjNZYr1od26RJ32KN/1NBCySTDOchD kvca4A++OuQ0HvSoNkPy4u/ZPO1VsZZG870ojUfHgHTf6bto/6ZrFrS8gpC5YInk8kaR9Nm26v5iY 0rqdoA6FMQMMZN1tJpDo1Yp0h8Pa+z24mPcVImvNnVxnBu30OV8hZd5UnvO4dfr06NMWLnve3gkud tIvul67IlcInvuVax/IYBZaeboVZ6BeOgNmDUWlVy2pH9QktYN0LRFmgXE3zO5qhMu366N1OizkP8 nj4j6cJQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdCQX-00000007ZKT-0xhF; Wed, 29 Jan 2025 18:04:37 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tdCPc-00000007ZHh-15Eb for linux-nvme@lists.infradead.org; Wed, 29 Jan 2025 18:03:45 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 86A085C5D28; Wed, 29 Jan 2025 18:02:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0551C4CED1; Wed, 29 Jan 2025 18:03:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738173819; bh=fGp2xaP4mmstBrpG7VZNDHnMwJnBSocGcTWYaJO1KJw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PBYvsP4apvQaGb4Xg2vfMDOZ/XPXBr88G4C3rEeQPOCRI2VJyLHGyKwb2+5bxXMs2 Pewr2CSX167/UwDcMOdO+KWEJr5vE9K5EMZqAA4MbQdpjlM1uaYki+4FfGOl9eoVrF 4OCmJmeOXJS6SEzOaWaWZbVhZfwPjRfk6szaisl22/zS8UE/CrFr+SRvuZNoVvp+40 ewAm3ooOnzzk4D085+rD7eonV1dMxrAo2ZrbTbKBNdXVWTxrLJcQ9wjYMUiS0f0XbP nlvDAJBOToR8bs6R6FY5sBi5OHnp/GJCUKu2YIRV/vWfITPsaDpp9DYXDRtTfaF5pB 3kTKJ1Hjq1HAg== Date: Wed, 29 Jan 2025 11:03:36 -0700 From: Keith Busch To: Christoph Hellwig Cc: Kanchan Joshi , josef@toxicpanda.com, dsterba@suse.com, clm@fb.com, axboe@kernel.dk, linux-btrfs@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com Subject: Re: [RFC 0/3] Btrfs checksum offload Message-ID: References: <20250129140207.22718-1-joshi.k@samsung.com> <20250129154025.GA7047@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250129154025.GA7047@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250129_100340_345520_D5C27806 X-CRM114-Status: GOOD ( 12.74 ) 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, Jan 29, 2025 at 04:40:25PM +0100, Christoph Hellwig wrote: > > > > Another potential benefit: if the device does the checksum, then I think > > btrfs could avoid the stable page writeback overhead and let the > > contents be changable all the way until it goes out on the wire. > > If the device generates the checksum (aka DIF insert) that problem goes > away. But we also lose integrity protection over the wire, which would > be unfortunate. If the "wire" is only PCIe, I don't see why it matters. What kind of wire corruption gets undetected by the protocol's encoding and LCRC that would get caught by the host's CRC payload?