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 BC61CC0218D for ; Wed, 29 Jan 2025 15:28:33 +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=SeZspGMtd29bXBRJEo6j1b1maNPj6nnM3pShwptmW2A=; b=u9FhjQKEnSXCVrju41c1RFJWuV 4l27UmkKIknvkUsekcXhL72wrTPw73st9G4URbynio7JOcNsoQiun3wDxzL4E9iEDe5MOh3CgSm54 JVxQW2rz21FnDs+FNz9FT86jYz28DR3TSX4uBC9V/YL454/4sEvoFzor9+AEKsYEB538WVKE8qxa5 Zs9jOe+OCC+VqgXIKT0ZcHd7DUxGAZE7be2gX8t/DsgIRHf5bIzlpn9FkHarL0mSUX6SW1xftFWxN tCoFQK7D/1CC7PjIhQyYnJHMyMW3C9WMpgxhTGENN2jV1JWm3GWeIPvWoKR3fM4E+FKbgrXU50ZQ/ NnfabTbA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1td9zS-00000007F9Y-1hRx; Wed, 29 Jan 2025 15:28:30 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1td9zP-00000007F9F-3q7Y for linux-nvme@lists.infradead.org; Wed, 29 Jan 2025 15:28:29 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id D26F5A41A20; Wed, 29 Jan 2025 15:26:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CDBC6C4CED3; Wed, 29 Jan 2025 15:28:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738164506; bh=SeZspGMtd29bXBRJEo6j1b1maNPj6nnM3pShwptmW2A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YElx4xGBKbiZmg/exChiKs++JAtGnxXODnvPFQa5wutbWImPHv1PuvB9WfYDr+97b sWYFohrvpcIW4NN7mJhDA1pW9x2VAfcvXgTDqp0aE/R3S1FsYciLUSbPW9J5lMx0YK uqGjynyy1FQgR+0ho/v3YZLB9MuAwVtMpemx51Ss2OKLcG8H4X4dYXRUqf+8BlulbG RO2k+5l/P+L1tJs4ha5c0BI+Apar/T7EYK9xO9v6ND/BpTVoqv0QuFkKXpNAuuffgo i3yiTcsI3VkziJ4ycdUI2pg5ckG/4PrJaU/Z+LVOXVj2mqu3yAKL7JrfRPTLlWTeq+ UlWr5/5QR2Oyw== Date: Wed, 29 Jan 2025 08:28:24 -0700 From: Keith Busch To: Kanchan Joshi Cc: josef@toxicpanda.com, dsterba@suse.com, clm@fb.com, axboe@kernel.dk, hch@lst.de, 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250129140207.22718-1-joshi.k@samsung.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250129_072828_017506_B6117CBC X-CRM114-Status: UNSURE ( 9.03 ) X-CRM114-Notice: Please train this message. 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 07:32:04PM +0530, Kanchan Joshi wrote: > There is value in avoiding Copy-on-write (COW) checksum tree on > a device that can anyway store checksums inline (as part of PI). > This would eliminate extra checksum writes/reads, making I/O > more CPU-efficient. 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. Though I feel the very specific device format constraints that can support an offload like this are a unfortunate.