[PATCH 0/5] Generic Ticket Spinlocks

[Palmer Dabbelt]

Peter sent an RFC out about a year ago
<https://lore.kernel.org/lkml/YHbBBuVFNnI4kjj3@hirez.programming.kicks-ass.net/>,
but after a spirited discussion it looks like we lost track of things.
IIRC there was broad consensus on this being the way to go, but there
was a lot of discussion so I wasn't sure.  Given that it's been a year,
I figured it'd be best to just send this out again formatted a bit more
explicitly as a patch.

This has had almost no testing (just a build test on RISC-V defconfig),
but I wanted to send it out largely as-is because I didn't have a SOB
from Peter on the code.  I had sent around something sort of similar in
spirit, but this looks completely re-written.  Just to play it safe I
wanted to send out almost exactly as it was posted.  I'd probably rename
this tspinlock and tspinlock_types, as the mis-match kind of makes my
eyes go funny, but I don't really care that much.  I'll also go through
the other ports and see if there's any more candidates, I seem to
remember there having been more than just OpenRISC but it's been a
while.

I'm in no big rush for this and given the complex HW dependencies I
think it's best to target it for 5.19, that'd give us a full merge
window for folks to test/benchmark it on their systems to make sure it's
OK.  RISC-V has a forward progress guarantee so we should be safe, but
these can always trip things up.