Re: [PATCH 4/7] xfs: allow blocking notifier chains with filesystem hooks

Christoph Hellwig
2024-01-02T10:28:04Z

On Sun, Dec 31, 2023 at 12:05:29PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Make it so that we can switch between notifier chain implementations for
> testing purposes. On the author's test system, calling an empty srcu
> notifier chain cost about 19ns per call, vs. 4ns for a blocking notifier
> chain. Hm. Might we actually want regular blocking notifiers?

Sounds like it. But what is important is that we really shouldn't
provide both and punt the decision to the user..