From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4DBEA1AB6C1; Wed, 11 Sep 2024 15:18:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726067931; cv=none; b=cCDbylWD4NPtLb3DXfF8n/oTbcwOTLZ/JYtHTpt09jrTYCjfyDGotdh+I9QjEl3lUr+WUERpEwNr1KbCMd9B5Z0toHC5OZkEJmMlW+qiREU1Oi6+TOMs5+XPMRwsFMVRDXTPQOB4L1H9fy3DwMJNmZ3mnuAWKgUz+TFtXhZuJbE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726067931; c=relaxed/simple; bh=ccPusGui9l+4uHYSFKd64E0OMOr0AoqgldLtmLoEqYI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EwmQtWus3ojPjlWXY1gB7JVUSO/j4yw8G/w/EiMJO5gUETr0mE7dHoQOQFS7Ads2gRU5PuIDbHjjCJ661PfzdBZLNQv7SyQ8nRCkvVu515rmsKt8r7zZit8eo4PfMVd1pZMExyaVmh8ERhySoLTkumkJQmtZCzkRMol4LeIAbTA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fqDcy7TJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fqDcy7TJ" 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> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240911081846.GB7372@lst.de> 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.