Re: [PATCH] rcu: use try_cmpxchg in check_cpu_stall

[Steven Rostedt]

On Wed, 1 Mar 2023 19:43:34 +0100
Uros Bizjak <ubizjak@xxxxxxxxx> wrote:

> On Wed, Mar 1, 2023 at 5:38 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> >
> > 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.  
> 
> Attached patch implements this suggestion.

I like it!

Anyway to make this more generic?

-- Steve