Re: [PATCH tip/core/rcu 1/9] rcu: Upgrade rcu_swap_protected() to rcu_replace()

[Peter Zijlstra]

On Thu, Oct 03, 2019 at 12:31:38PM -0400, Mathieu Desnoyers wrote:
> We might want to consider simply using xchg() here.

As stated elsewhere, xchg() is an atomic op with full ordering, IOW it
is stupid expensive for what needs to be done.