Re: [PATCH] rcu: use try_cmpxchg in check_cpu_stall

[Steven Rostedt]

On Wed, 1 Mar 2023 11:28:47 +0100
Uros Bizjak <ubizjak@xxxxxxxxx> wrote:

> These benefits are the reason the change to try_cmpxchg was accepted
> also in the linear code elsewhere in the linux kernel, e.g. [2,3] to
> name a few commits, with a thumbs-up and a claim that the new code is
> actually *clearer* at the merge commit [4].

I'll say it here too. I really like Joel's suggestion of having a
cmpxchg_success() that does not have the added side effect of modifying the
old variable.

I think that would allow for the arch optimizations that you are trying to
achieve, as well as remove the side effect that might cause issues down the
road.

-- Steve