Messages in this thread Patch in this message | | | From | Davidlohr Bueso <> | Subject | [PATCH 5/5] locking/mcs: Use acquire/release semantics | Date | Mon, 21 Sep 2015 13:17:56 -0700 |
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As such, weakly ordered archs can benefit from more relaxed use of barriers when locking/unlocking.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de> --- kernel/locking/mcs_spinlock.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h index fd91aaa..5b9102a 100644 --- a/kernel/locking/mcs_spinlock.h +++ b/kernel/locking/mcs_spinlock.h @@ -67,7 +67,7 @@ void mcs_spin_lock(struct mcs_spinlock **lock, struct mcs_spinlock *node) node->locked = 0; node->next = NULL; - prev = xchg(lock, node); + prev = xchg_acquire(lock, node); if (likely(prev == NULL)) { /* * Lock acquired, don't need to set node->locked to 1. Threads @@ -98,7 +98,7 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node) /* * Release the lock by setting it to NULL */ - if (likely(cmpxchg(lock, node, NULL) == node)) + if (likely(cmpxchg_release(lock, node, NULL) == node)) return; /* Wait until the next pointer is set */ while (!(next = READ_ONCE(node->next))) -- 2.1.4
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