From: Keith Busch <kbusch@kernel.org>
To: Adrian Huang12 <ahuang12@lenovo.com>
Cc: Christoph Hellwig <hch@lst.de>, John Garry <john.garry@linux.dev>,
"sagi@grimberg.me" <sagi@grimberg.me>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
Jiwei JW10 Sun <sunjw10@lenovo.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>
Subject: Re: [External] Re: [PATCH] Revert "nvme-pci: clamp max_hw_sectors based on DMA optimized limitation"
Date: Fri, 9 Oct 2026 09:37:18 -0600 [thread overview]
Message-ID: <askKLgBhLzjaOyfF@kbusch-mbp> (raw)
In-Reply-To: <TPZP295MB0013C6E51C73799E49B8EFF4B3922@TPZP295MB0013.TWNP295.PROD.OUTLOOK.COM>
On Fri, Oct 09, 2026 at 09:11:56AM +0000, Adrian Huang12 wrote:
>
> BTW, with this reverted patch, I'm setting up the test environment to
> check whether the issue does not appear with a newer kernel that
> includes the updated IOMMU subsystem. I'll share the results by the
> end of next week.
It does sound like an IOMMU implementation issue if the revert regresses
your testing. Let's say the application wants to write 1MB of data:
we're DMA mapping the same total amount either way, so I don't think it
should have been more efficient for the driver to send eight 128k
mapping requests vs a single 1MB.
next prev parent reply other threads:[~2026-10-09 15:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-06 12:02 [PATCH] Revert "nvme-pci: clamp max_hw_sectors based on DMA optimized limitation" Christoph Hellwig
2026-10-08 7:36 ` John Garry
2026-10-08 12:37 ` Christoph Hellwig
2026-10-09 9:11 ` [External] " Adrian Huang12
2026-10-09 15:37 ` Keith Busch [this message]
2026-10-12 8:42 ` John Garry
2026-10-12 12:17 ` Christoph Hellwig
2026-10-12 14:39 ` John Garry
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