From: Christoph Hellwig <hch@infradead.org>
To: Trond Myklebust <trondmy@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
linux-fsdevel@vger.kernel.org,
Anna Schumaker <anna.schumaker@oracle.com>
Subject: Re: NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19
Date: Wed, 17 Dec 2025 01:53:10 -0800 [thread overview]
Message-ID: <aUJ9hliJJarv23Uj@infradead.org> (raw)
In-Reply-To: <aUJ4rjyAOW3EWC-k@infradead.org>
On Wed, Dec 17, 2025 at 01:32:30AM -0800, Christoph Hellwig wrote:
> Hi all,
>
> the merge of this branch causes NFS lookup operation to shoot up a lot
> for me. And with merge I mean merge - both parent of the merge on their
> own are fine.
>
> With the script below that simulates running python scripts with lots
> of imports that was created to benchmark delegation performance, the
> number of lookups in the measurement period shoots up from 4 to about
> 410000, which is a bit suboptimal. I have no idea how this could
> happen, but it must be related to some sort of pathname lookup changes
> I guess. Other operations looks roughly the same.
To further pin this down, I rebased the patches from the NFS pull request
on top of the baseline (d358e5254674b70f34c847715ca509e46eb81e6f) and
bisected that. This ends up in:
NFS: Shortcut lookup revalidations if we have a directory delegation
next prev parent reply other threads:[~2025-12-17 9:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-11 14:07 Trond Myklebust
2025-12-12 10:09 ` pr-tracker-bot
2025-12-17 9:32 ` NFS dentry caching regression? was " Christoph Hellwig
2025-12-17 9:53 ` Christoph Hellwig [this message]
2025-12-17 14:23 ` [External] : " Anna Schumaker
2025-12-17 22:03 ` Anna Schumaker
2025-12-18 5:13 ` 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=aUJ9hliJJarv23Uj@infradead.org \
--to=hch@infradead.org \
--cc=anna.schumaker@oracle.com \
--cc=brauner@kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=trondmy@kernel.org \
--cc=viro@zeniv.linux.org.uk \
/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
all inboxes | Powered by JetHome®