locking/rwbase: Optimize rwbase_read_trylock
authorDavidlohr Bueso <dave@stgolabs.net>
Mon, 20 Sep 2021 05:20:30 +0000 (22:20 -0700)
committerPeter Zijlstra <peterz@infradead.org>
Thu, 7 Oct 2021 11:51:07 +0000 (13:51 +0200)
commitc78416d122243c92992a1d1063f17ddd0bc80e6c
tree91ddd15c967aec7d0f1631b65b9ca8a696feb570
parent3f48565beb7219bbe8332391fc4ca758054b00c5
locking/rwbase: Optimize rwbase_read_trylock

Instead of a full barrier around the Rmw insn, micro-optimize
for weakly ordered archs such that we only provide the required
ACQUIRE semantics when taking the read lock.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20210920052031.54220-2-dave@stgolabs.net
kernel/locking/rwbase_rt.c