From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Eric Biggers <ebiggers@kernel.org>,
Christoph Hellwig <hch@lst.de>,
Carlos Llamas <cmllamas@google.com>,
Keith Busch <kbusch@meta.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
axboe@kernel.dk, Hannes Reinecke <hare@suse.de>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Subject: Re: [PATCHv4 5/8] iomap: simplify direct io validity check
Date: Tue, 4 Nov 2025 12:35:35 +0100 [thread overview]
Message-ID: <20251104113535.GA14479@lst.de> (raw)
In-Reply-To: <aQjzwh3iAQREjndH@kbusch-mbp>
On Mon, Nov 03, 2025 at 11:26:10AM -0700, Keith Busch wrote:
> I've been using these memory alignment capabilities in production for
> quite some time without issue on real hardware, and it's proven very
> useful at reducing memory and cpu utilization because that's really how
> the data alignment comes into the services responisble for running the
> disk io, and the alignment is outside the service's control.
>
> Christoph is testing different use cases with check summing and finding
> much of the infrastructure wasn't ready to accept the more arbitrary
> memory offsets and lengths.
Well, I've mostly just wired up the alignment reporting to the legacy
XFS ioctl, and now xfstests actually tried it. Which found breakage
in the PI code and in null_blk pretty quickly, and I suspect it might
find more in drivers that access the data in software and don't just
DMA map it.
next prev parent reply other threads:[~2025-11-04 11:35 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-27 14:12 [PATCHv4 0/8] Keith Busch
2025-08-27 14:12 ` [PATCHv4 1/8] block: check for valid bio while splitting Keith Busch
2025-08-31 0:40 ` Martin K. Petersen
2025-08-27 14:12 ` [PATCHv4 2/8] block: add size alignment to bio_iov_iter_get_pages Keith Busch
2025-08-31 0:40 ` Martin K. Petersen
2025-08-27 14:12 ` [PATCHv4 3/8] block: align the bio after building it Keith Busch
2025-08-31 0:41 ` Martin K. Petersen
2025-09-02 5:23 ` Christoph Hellwig
2025-08-27 14:12 ` [PATCHv4 4/8] block: simplify direct io validity check Keith Busch
2025-08-27 14:12 ` [PATCHv4 5/8] iomap: " Keith Busch
2025-10-27 16:25 ` Carlos Llamas
2025-10-27 16:42 ` Keith Busch
2025-10-27 17:12 ` Carlos Llamas
2025-10-28 22:47 ` Carlos Llamas
2025-10-28 22:56 ` Eric Biggers
2025-10-28 23:03 ` Eric Biggers
2025-10-29 7:06 ` Christoph Hellwig
2025-10-30 17:40 ` Eric Biggers
2025-10-31 9:18 ` Christoph Hellwig
2025-11-03 18:10 ` Eric Biggers
2025-11-03 18:26 ` Keith Busch
2025-11-04 11:35 ` Christoph Hellwig [this message]
2025-10-30 4:54 ` Carlos Llamas
2025-08-27 14:12 ` [PATCHv4 6/8] block: remove bdev_iter_is_aligned Keith Busch
2025-08-27 14:12 ` [PATCHv4 7/8] blk-integrity: use simpler alignment check Keith Busch
2025-08-27 14:12 ` [PATCHv4 8/8] iov_iter: remove iov_iter_is_aligned Keith Busch
2025-09-09 16:27 ` [PATCHv4 0/8] Jens Axboe
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