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| author | Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> | 2016-09-19 05:23:52 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-09-22 15:25:51 +0200 |
| commit | b193049375b04df3ada8c3347b7083db95918bc3 (patch) | |
| tree | e72b1e31ee8d3b04008b13313b89fe44b1d95d3e | |
| parent | 7cf0f1426a909ed36a8b349a4a975e0d68b5edad (diff) | |
| download | op-kernel-dev-b193049375b04df3ada8c3347b7083db95918bc3.zip op-kernel-dev-b193049375b04df3ada8c3347b7083db95918bc3.tar.gz | |
locking/pv-qspinlock: Use cmpxchg_release() in __pv_queued_spin_unlock()
cmpxchg_release() is more lighweight than cmpxchg() on some archs(e.g.
PPC), moreover, in __pv_queued_spin_unlock() we only needs a RELEASE in
the fast path(pairing with *_try_lock() or *_lock()). And the slow path
has smp_store_release too. So it's safe to use cmpxchg_release here.
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: virtualization@lists.linux-foundation.org
Cc: waiman.long@hpe.com
Link: http://lkml.kernel.org/r/1474277037-15200-2-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/locking/qspinlock_paravirt.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h index 3acf16d..e3b5520 100644 --- a/kernel/locking/qspinlock_paravirt.h +++ b/kernel/locking/qspinlock_paravirt.h @@ -540,7 +540,7 @@ __visible void __pv_queued_spin_unlock(struct qspinlock *lock) * unhash. Otherwise it would be possible to have multiple @lock * entries, which would be BAD. */ - locked = cmpxchg(&l->locked, _Q_LOCKED_VAL, 0); + locked = cmpxchg_release(&l->locked, _Q_LOCKED_VAL, 0); if (likely(locked == _Q_LOCKED_VAL)) return; |
