From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: <linux-iio@vger.kernel.org>
Subject: IIO related heads up - on ARM64 you are likely to see DMA buffers being bounced soon...
Date: Fri, 9 Jun 2023 18:08:02 +0100 [thread overview]
Message-ID: <20230609180802.0000254b@Huawei.com> (raw)
Catalin's work to reduce the size of minimum allocation sizes
from kmalloc on ARM64 relies on a heuristic where small
buffers are always bounced to ensure DMA safety.
https://lore.kernel.org/all/20230531154836.1366225-1-catalin.marinas@arm.com/
Now this shouldn't break any IIO drivers but it might (at least in theory)
have a performance impact.
I'm curious on whether anyone cares enough about this?
Long term, if this approach ends up adopted on all architectures that
currently have ARCH_KMALLOC_MINALIGN set above 8 bytes we can get rid
of the explicit handling of DMA buffers in IIO as they will mostly be
bounced anyway - with the exception of a few that are bigger than the
relevant cacheline size.
Jonathan
reply other threads:[~2023-06-09 17:08 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230609180802.0000254b@Huawei.com \
--to=jonathan.cameron@huawei.com \
--cc=linux-iio@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.