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Groups > linux.kernel > #1203154

[PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL

From Waiman Long <Waiman.Long@hp.com>
Newsgroups linux.kernel
Subject [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL
Date 2015-08-08 05:20 +0200
Message-ID <pV2PU-3d1-9@gated-at.bofh.it> (permalink)
References <pV2PT-3d1-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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@hp.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.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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[PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL Waiman Long <Waiman.Long@hp.com> - 2015-08-08 05:20 +0200
  Re: [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with  _Q_SLOW_VAL Peter Zijlstra <peterz@infradead.org> - 2015-08-08 08:10 +0200
    Re: [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with  _Q_SLOW_VAL Waiman Long <waiman.long@hp.com> - 2015-08-14 04:10 +0200

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