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Date: Fri, 7 Aug 2015 23:17:56 -0400
From: Waiman Long <Waiman.Long@...com>
To: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
Scott J Norton <scott.norton@...com>,
Douglas Hatch <doug.hatch@...com>,
Davidlohr Bueso <dave@...olabs.net>,
Waiman Long <Waiman.Long@...com>
Subject: [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL
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.Long@...com>
Reviewed-by: Davidlohr Bueso <dave@...olabs.net>
---
kernel/locking/qspinlock_paravirt.h | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index c8e6e9a..6eafb9e 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -364,8 +364,7 @@ __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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