If _Q_SLOW_VAL has been set, the vCPU state must have been vcpu_hashed.
The extra check at the end of __pv_queued_spin_unlock() is unnecessary
and so is removed.
Signed-off-by: Waiman Long <waiman.l...@hpe.com>
Reviewed-by: Davidlohr Bueso <d...@stgolabs.net>
---
kernel/locking/qspinlock_paravirt.h | 6 +-----
1 files changed, 1 insertions(+), 5 deletions(-)
diff --git a/kernel/locking/qspinlock_paravirt.h
b/kernel/locking/qspinlock_paravirt.h
index c8e6e9a..f0450ff 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -267,7 +267,6 @@ static void pv_wait_head(struct qspinlock *lock, struct
mcs_spinlock *node)
}
if (!lp) { /* ONCE */
- WRITE_ONCE(pn->state, vcpu_hashed);
lp = pv_hash(lock, pn);
/*
@@ -275,11 +274,9 @@ static void pv_wait_head(struct qspinlock *lock, struct
mcs_spinlock *node)
* when we observe _Q_SLOW_VAL in
__pv_queued_spin_unlock()
* we'll be sure to be able to observe our hash entry.
*
- * [S] pn->state
* [S] <hash> [Rmw] l->locked ==
_Q_SLOW_VAL
* MB RMB
* [RmW] l->locked = _Q_SLOW_VAL [L] <unhash>
- * [L] pn->state
*
* Matches the smp_rmb() in __pv_queued_spin_unlock().
*/
@@ -364,8 +361,7 @@ __visible void __pv_queued_spin_unlock(struct qspinlock
*lock)
* vCPU is harmless other than the additional latency in completing
* the unlock.
*/
- if (READ_ONCE(node->state) == vcpu_hashed)
- pv_kick(node->cpu);
+ pv_kick(node->cpu);
}
/*
* Include the architecture specific callee-save thunk of the
--
1.7.1
--
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