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From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@meta.com>
Cc: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	hch@lst.de, axboe@kernel.dk, Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH 2/2] nvme: remove virtual boundary for sgl capable devices
Date: Wed, 6 Aug 2025 16:55:14 +0200	[thread overview]
Message-ID: <20250806145514.GB20102@lst.de> (raw)
In-Reply-To: <20250805195608.2379107-2-kbusch@meta.com>

On Tue, Aug 05, 2025 at 12:56:08PM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
> 
> The nvme virtual boundary is only for the PRP format. Devices that can
> use the SGL format don't need it for IO queues. Drop reporting it for
> such PCIe devices; fabrics target will continue to use the limit.

That's not quite true any more as of 6.17.  We now also rely it for
efficiently mapping multiple segments into a single IOMMU mapping.
So by not enforcing it for IOMMU mode.  In many cases we're better
off splitting I/O rather forcing a non-optimized IOMMU mapping.


  reply	other threads:[~2025-08-06 14:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-05 19:56 [PATCH 1/2] block: accumulate segment page gaps per bio Keith Busch
2025-08-05 19:56 ` [PATCH 2/2] nvme: remove virtual boundary for sgl capable devices Keith Busch
2025-08-06 14:55   ` Christoph Hellwig [this message]
2025-08-06 15:04     ` Keith Busch
2025-08-05 20:32 ` [PATCH 1/2] block: accumulate segment page gaps per bio Caleb Sander Mateos
2025-08-05 20:52   ` Keith Busch
2025-08-05 22:52 ` Keith Busch
2025-08-06 14:53   ` Christoph Hellwig
2025-08-06 15:17     ` Keith Busch
2025-08-06 14:56 ` Christoph Hellwig
2025-08-06 15:44   ` Keith Busch
2025-08-10 14:31     ` Christoph Hellwig
2025-08-11 15:27       ` Keith Busch
2025-08-11 16:17         ` Christoph Hellwig
2025-08-20 19:22           ` Keith Busch

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