From: Waiman Long <Waiman.Long@hp.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Scott J Norton <scott.norton@hp.com>,
Douglas Hatch <doug.hatch@hp.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Waiman Long <Waiman.Long@hp.com>
Subject: [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL
Date: Fri, 7 Aug 2015 23:17:56 -0400 [thread overview]
Message-ID: <1439003881-17349-2-git-send-email-Waiman.Long@hp.com> (raw)
In-Reply-To: <1439003881-17349-1-git-send-email-Waiman.Long@hp.com>
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
next prev parent reply other threads:[~2015-08-08 3:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-08 3:17 [PATCH v5 0/6] locking/qspinlock: Enhance pvqspinlock performance Waiman Long
2015-08-08 3:17 ` Waiman Long [this message]
2015-08-08 6:02 ` [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL Peter Zijlstra
2015-08-14 2:07 ` Waiman Long
2015-08-08 3:17 ` [PATCH v5 2/6] locking/pvqspinlock: Add pending bit support Waiman Long
2015-08-08 3:17 ` [PATCH v5 3/6] locking/pvqspinlock: Collect slowpath lock statistics Waiman Long
2015-08-08 3:17 ` [PATCH v5 4/6] locking/pvqspinlock, x86: Optimize PV unlock code path Waiman Long
2015-08-08 3:18 ` [PATCH v5 5/6] locking/pvqspinlock: Allow vCPUs kick-ahead Waiman Long
2015-08-08 3:18 ` [PATCH v5 6/6] locking/pvqspinlock: Queue node adaptive spinning Waiman Long
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