Messages in this thread | | | Date | Wed, 4 Jan 2023 15:58:52 -0500 | From | Alan Stern <> | Subject | Re: Internal vs. external barriers (was: Re: Interesting LKMM litmus test) |
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On Wed, Jan 04, 2023 at 04:37:14PM +0100, Andrea Parri wrote: > Sounds good to me too. I'm trying to remember why we went for the LKW > event to model smp_mb__after_unlock_lock() (as opposed to the LKR event, > as suggested above/in po-unlock-lock-po).
I don't remember either, but with the LKR event it would be awkward to include the co part of (co | po) in the smp_mb__after_unlock_lock() definition. You'd have to write something like ((co? ; rf) | po).
Aside from that, I don't think using LKR vs. LKW makes any difference.
> Anyway, I currently see no > issue with the above (we know that LKW and LKR come paired), and I think > it's good to merge the two notions of "unlock-lock pair" if possible.
Indeed. It also would eliminate questions about why po-unlock-lock-po doesn't include the co term.
Alan
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