From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
brauner@kernel.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] iomap: add a separate bio_set for iomap_split_ioend
Date: Tue, 30 Jun 2026 07:17:04 +0200 [thread overview]
Message-ID: <20260630051704.GD20771@lst.de> (raw)
In-Reply-To: <20260629225831.GG6095@frogsfrogsfrogs>
On Mon, Jun 29, 2026 at 03:58:31PM -0700, Darrick J. Wong wrote:
> On Mon, Jun 29, 2026 at 02:52:29PM +0200, Christoph Hellwig wrote:
> > iomap_split_ioend can split bios that already come from
> > iomap_ioend_bioset and thus deadlock when the bioset is exhausted.
> >
> > Add a separate bio_set to avoid this deadlock.
>
> What happens if &iomap_ioend_split_bioset is exhausted?
mempool_alloc will block waiting for an ioend to finish.
> Won't that also stall the ioend submission?
Yes, but at least it won't deadlock, unlike the case where we're
waiting for the parent one to finish. (multiply a few times
as there is more than one entry in the mempool, which is what's
saving our ass in practice)
next prev parent reply other threads:[~2026-06-30 5:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-29 12:52 [PATCH] iomap: add a separate bio_set for iomap_split_ioend Christoph Hellwig
2026-06-29 22:58 ` Darrick J. Wong
2026-06-30 5:17 ` Christoph Hellwig [this message]
2026-06-30 10:59 ` Christian Brauner
2026-07-07 5:04 ` Christoph Hellwig
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=20260630051704.GD20771@lst.de \
--to=hch@lst.de \
--cc=brauner@kernel.org \
--cc=djwong@kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-xfs@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox