From: Keith Busch <kbusch@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Ben Copeland <ben.copeland@linaro.org>,
linux-kernel@vger.kernel.org, lkft-triage@lists.linaro.org,
regressions@lists.linux.dev, linux-nvme@lists.infradead.org,
Dan Carpenter <dan.carpenter@linaro.org>,
axboe@kernel.dk, sagi@grimberg.me, iommu@lists.linux.dev,
Leon Romanovsky <leonro@nvidia.com>
Subject: Re: next-20250627: IOMMU DMA warning during NVMe I/O completion after 06cae0e3f61c
Date: Thu, 3 Jul 2025 08:29:23 -0600 [thread overview]
Message-ID: <aGaTw7SzermpfiD7@kbusch-mbp> (raw)
In-Reply-To: <20250703093042.GA7387@lst.de>
On Thu, Jul 03, 2025 at 11:30:42AM +0200, Christoph Hellwig wrote:
> I think the idea to reconstruct the dma addresses from PRPs should
> be considered a failure by now. It works fine for SGLs, but for
> PRPs we're better off just stashing them away. Bob, can you try
s/Bob/Ben
> something like the patch below? To be fully safe it needs a mempool,
> and it could use some cleanups, but it does pass testing on my setup
> here, so I'd love to see if if fixes your issue.
Thanks for confirming.
While this is starting to look a bit messy, I believe it's still an
overall win: you've cut down the vector walking in the setup path from 3
to 1, which reduces a non-trivial amount of overhead for even moderately
sized IO.
next prev parent reply other threads:[~2025-07-03 14:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20250630075218epcas5p1f3d467fffa468cac0ccd012c193e94df@epcas5p1.samsung.com>
2025-06-30 7:50 ` next-20250627: IOMMU DMA warning during NVMe I/O completion after 06cae0e3f61c Ben Copeland
2025-06-30 13:33 ` Christoph Hellwig
2025-06-30 19:51 ` Ben Copeland
2025-07-01 19:43 ` Keith Busch
2025-06-30 20:25 ` Keith Busch
2025-07-01 0:54 ` Keith Busch
2025-07-01 13:05 ` Ben Copeland
2025-07-01 14:20 ` Keith Busch
2025-07-01 13:29 ` Christoph Hellwig
2025-07-01 15:58 ` Leon Romanovsky
2025-07-01 21:00 ` Keith Busch
2025-07-03 9:30 ` Christoph Hellwig
2025-07-03 14:29 ` Keith Busch [this message]
2025-07-03 15:13 ` Ben Copeland
2025-07-03 5:54 ` Kanchan Joshi
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