Re: [RFC PATCH 1/4] hazptr: Add initial implementation of hazard pointers

From: Linus Torvalds
Date: Fri Sep 27 2024 - 13:23:53 EST


On Fri, 27 Sept 2024 at 10:17, Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
>
> The barrier() is ineffective at fixing the issue.
> It does not prevent the compiler CSE from losing the
> address dependency:

Ok. Thanks for actually specifying code.

That needs to be

(a) in a comment

(b) the value barrier needs to be on *both* values so that the order
of the equality testing doesn't matter.

> I'm preparing a small series that aims to show how a minimal
> hazard pointer implementation can help improve common scenarios:

I want actual numbers on real loads. Just so you know. Not "this can
help". But "this actually really _does_ help".

Linus