From: Davidlohr Bueso <dave@stgolabs.net>
To: Waiman Long <Waiman.Long@hpe.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Scott J Norton <scott.norton@hp.com>,
Douglas Hatch <doug.hatch@hp.com>
Subject: Re: [PATCH v6 1/6] locking/qspinlock: relaxes cmpxchg & xchg ops in native code
Date: Fri, 11 Sep 2015 15:27:44 -0700 [thread overview]
Message-ID: <20150911222744.GC19736@linux-q0g1.site> (raw)
In-Reply-To: <1441996658-62854-2-git-send-email-Waiman.Long@hpe.com>
On Fri, 11 Sep 2015, Waiman Long wrote:
>@@ -46,7 +46,7 @@ static inline bool virt_queued_spin_lock(struct qspinlock *lock)
> if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
> return false;
>
>- while (atomic_cmpxchg(&lock->val, 0, _Q_LOCKED_VAL) != 0)
>+ while (atomic_cmpxchg_acquire(&lock->val, 0, _Q_LOCKED_VAL) != 0)
> cpu_relax();
This code has changed with Peter's recent ccas fix. And the whole virt_queued_spin_lock()
thing will now be under pv configs. So this doesn't apply to native code anymore, so it
looks like it should be dropped altogether.
Thanks,
Davidlohr
next prev parent reply other threads:[~2015-09-11 22:27 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-11 18:37 [PATCH v6 0/6] locking/qspinlock: Enhance pvqspinlock performance Waiman Long
2015-09-11 18:37 ` [PATCH v6 1/6] locking/qspinlock: relaxes cmpxchg & xchg ops in native code Waiman Long
2015-09-11 22:27 ` Davidlohr Bueso [this message]
2015-09-14 12:06 ` Peter Zijlstra
2015-09-14 18:40 ` Waiman Long
2015-09-14 15:16 ` Waiman Long
2015-09-11 18:37 ` [PATCH v6 2/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL Waiman Long
2015-09-18 8:50 ` [tip:locking/core] locking/pvqspinlock: Kick the PV CPU unconditionally when _Q_SLOW_VAL tip-bot for Waiman Long
2015-09-11 18:37 ` [PATCH v6 3/6] locking/pvqspinlock, x86: Optimize PV unlock code path Waiman Long
2015-09-11 18:37 ` [PATCH v6 4/6] locking/pvqspinlock: Collect slowpath lock statistics Waiman Long
2015-09-11 23:13 ` Davidlohr Bueso
2015-09-14 15:25 ` Waiman Long
2015-09-14 21:41 ` Davidlohr Bueso
2015-09-15 3:47 ` Waiman Long
2015-09-11 18:37 ` [PATCH v6 5/6] locking/pvqspinlock: Allow 1 lock stealing attempt Waiman Long
2015-09-14 13:57 ` Peter Zijlstra
2015-09-14 19:02 ` Waiman Long
2015-09-14 14:00 ` Peter Zijlstra
2015-09-14 19:15 ` Waiman Long
2015-09-14 19:38 ` Waiman Long
2015-09-15 8:24 ` Peter Zijlstra
2015-09-15 15:29 ` Waiman Long
2015-09-16 15:01 ` Peter Zijlstra
2015-09-17 15:08 ` Waiman Long
2015-09-14 14:04 ` Peter Zijlstra
2015-09-14 19:19 ` Waiman Long
2015-09-11 18:37 ` [PATCH v6 6/6] locking/pvqspinlock: Queue node adaptive spinning Waiman Long
2015-09-14 14:10 ` Peter Zijlstra
2015-09-14 19:37 ` Waiman Long
2015-09-15 8:38 ` Peter Zijlstra
2015-09-15 15:32 ` Waiman Long
2015-09-16 15:03 ` Peter Zijlstra
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