Messages in this thread | | | Date | Wed, 1 Mar 2023 15:18:26 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] rcu: use try_cmpxchg in check_cpu_stall |
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On Wed, 1 Mar 2023 12:08:20 -0800 "Paul E. McKenney" <paulmck@kernel.org> wrote:
> > Attached patch implements this suggestion. > > Please help me out here. > > Why on earth are we even discussing making this change to code that > normally never executes? Performance is not a consideration here. > > What am I missing here? Is there some sort of forward-progress > issue that this change addresses?
Well, we sorta hijacked this thread. It turned into a more general discussion, as there is code that this change will be useful for (ring_buffer.c), but we just happen to be having the discussion here.
Where it will at most remove some text and give you back a few extra bytes of memory ;-)
But if we do use cmpxchg_success() IMHO, it does improve readability.
> - cmpxchg(&rcu_state.jiffies_stall, js, jn) == js) { > + cmpxchg_success(&rcu_state.jiffies_stall, js, jn)) {
-- Steve
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