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 ED2E8EE57C0 for ; Wed, 11 Sep 2024 15:22:40 +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=UZu8AW0BeVf37W1CKuToQnEcN6erfZui2kj8yTIDt0U=; b=AaDjyoPIyFUV5csLIuXVRcvpxL yfXCEzpa7ojQUVSHq/JDRt9kUGSYNjKeMR7ayWvAe7g7YLwRnALFi2vF3ddV0gVm8kF64QAMhs+ZV 1Blna3UpCrgIIVDNxE8D+tSQQX4VU84sWmnX4Pu6Q/+SP/H2FLeZulH3afrkcZjDFO0gh/kAC9dbS WdM66djXeHRpgqKqR8EVHjPtrS+1yye4gp4dWVrD/RsUy64VcL8sMOBBAEzERKTqObuWJ0MUkKVJf sbvNWegiY2htFNdJVIKZmLjlCIvMX+og5fe1gPulI8UwCDd5lL2lTo2/BeyJdLFtSdKA7IiqQu5Rf mMnqh2jA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1soPAy-0000000A84M-3QSr; Wed, 11 Sep 2024 15:22:36 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1soP7L-0000000A6i5-33Md for linux-nvme@lists.infradead.org; Wed, 11 Sep 2024 15:18:53 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id A84605C0295; Wed, 11 Sep 2024 15:18:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 584A3C4CEC5; Wed, 11 Sep 2024 15:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1726067930; bh=ccPusGui9l+4uHYSFKd64E0OMOr0AoqgldLtmLoEqYI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fqDcy7TJbQkf745PlXaAf/KeypPhhV5acD0o717aenLvheqSeXY3kLogzRjx6H5+9 TKZdRjlLyo/SF4rG5N4gr/KJGpVqIxTZRa7nkUrLXjIsolhy+vn9cNSOf7FW0vSTe5 mfgafYzdtGx6WjkZCJ1GWJ4DWZ7O9/HTPy6QRiwfVC2qYPDHnnWfa4SubT0DbFXLRi ocuF8+/TLMd+jfSrxvgQiJhk1jyBLdymctdkPFpyAjeeDDiN9GWS5KS89VValAwfaG ohskAH93ZjMc2eqdJ0lNbQI9EV5J4j1e6fU9DuJ4gUTJmN8vab9wRcgVuOpTdOUJdG IdveCmvioaA9A== Date: Wed, 11 Sep 2024 09:18:48 -0600 From: Keith Busch To: Christoph Hellwig Cc: Keith Busch , axboe@kernel.dk, martin.petersen@oracle.com, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, sagi@grimberg.me Subject: Re: [PATCHv3 08/10] blk-integrity: remove inappropriate limit checks Message-ID: References: <20240904152605.4055570-1-kbusch@meta.com> <20240904152605.4055570-9-kbusch@meta.com> <20240910154526.GH23805@lst.de> <20240911081846.GB7372@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240911081846.GB7372@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240911_081851_830649_A8C028AC X-CRM114-Status: GOOD ( 20.22 ) 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, Sep 11, 2024 at 10:18:46AM +0200, Christoph Hellwig wrote: > On Tue, Sep 10, 2024 at 10:21:09AM -0600, Keith Busch wrote: > > I was hoping to not introduce another queue limit for the metadata > > virt_boundary_mask. We could remove the virt_boundary from the NVMe PCI > > driver if it supports SGL's and then we're fine. But we're commiting to > > that data format for all IO even if PRP might have been more efficient. > > That might be alright, though. > > The real question is if we actually want that. If we want to take > fully advantage of the new dma mapping API that Leon is proposing we'd > need to impose a similar limit. And a lot of these super tiny SGL > segments probably aren't very efficient to start with. Something that > bounce buffers a page worth of PI tuples might end up beeing more > efficient in the end. Yes, a bounce buffer is more efficient for the device side of the transaction. We have the infrastructure for it when the integrity data comes from user space addresses, so I suppose we could introduce a "kern" equivalent. But currently, instead of many small SGL's stiched together in a single command, we have the same small SGLs in their own commands. I think this patch set is a step in the right direction, and doesn't preclude bounce optimizations.