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From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, mingo@kernel.org,
	boqun.feng@gmail.com, paulmck@linux.vnet.ibm.com,
	catalin.marinas@arm.com, Waiman Long <longman@redhat.com>
Subject: Re: [PATCH 10/10] locking/qspinlock: Elide back-to-back RELEASE operations with smp_wmb()
Date: Thu, 5 Apr 2018 19:28:08 +0200	[thread overview]
Message-ID: <20180405172808.GG4082@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1522947547-24081-11-git-send-email-will.deacon@arm.com>

On Thu, Apr 05, 2018 at 05:59:07PM +0100, Will Deacon wrote:
> @@ -340,12 +341,17 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
>  		goto release;
>  
>  	/*
> +	 * Ensure that the initialisation of @node is complete before we
> +	 * publish the updated tail and potentially link @node into the
> +	 * waitqueue.
> +	 */
> +	smp_wmb();

Maybe an explicit note to where the matching barrier lives..

WARNING: multiple messages have this Message-ID (diff)
From: peterz@infradead.org (Peter Zijlstra)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 10/10] locking/qspinlock: Elide back-to-back RELEASE operations with smp_wmb()
Date: Thu, 5 Apr 2018 19:28:08 +0200	[thread overview]
Message-ID: <20180405172808.GG4082@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1522947547-24081-11-git-send-email-will.deacon@arm.com>

On Thu, Apr 05, 2018 at 05:59:07PM +0100, Will Deacon wrote:
> @@ -340,12 +341,17 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
>  		goto release;
>  
>  	/*
> +	 * Ensure that the initialisation of @node is complete before we
> +	 * publish the updated tail and potentially link @node into the
> +	 * waitqueue.
> +	 */
> +	smp_wmb();

Maybe an explicit note to where the matching barrier lives..

  reply	other threads:[~2018-04-05 17:28 UTC|newest]

Thread overview: 94+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-05 16:58 [PATCH 00/10] kernel/locking: qspinlock improvements Will Deacon
2018-04-05 16:58 ` Will Deacon
2018-04-05 16:58 ` [PATCH 01/10] locking/qspinlock: Don't spin on pending->locked transition in slowpath Will Deacon
2018-04-05 16:58   ` Will Deacon
2018-04-05 16:58 ` [PATCH 02/10] locking/qspinlock: Remove unbounded cmpxchg loop from locking slowpath Will Deacon
2018-04-05 16:58   ` Will Deacon
2018-04-05 17:07   ` Peter Zijlstra
2018-04-05 17:07     ` Peter Zijlstra
2018-04-06 15:08     ` Will Deacon
2018-04-06 15:08       ` Will Deacon
2018-04-05 17:13   ` Peter Zijlstra
2018-04-05 17:13     ` Peter Zijlstra
2018-04-05 21:16   ` Waiman Long
2018-04-05 21:16     ` Waiman Long
2018-04-06 15:08     ` Will Deacon
2018-04-06 15:08       ` Will Deacon
2018-04-06 20:50   ` Waiman Long
2018-04-06 20:50     ` Waiman Long
2018-04-06 21:09     ` Paul E. McKenney
2018-04-06 21:09       ` Paul E. McKenney
2018-04-07  8:47       ` Peter Zijlstra
2018-04-07  8:47         ` Peter Zijlstra
2018-04-07 23:37         ` Paul E. McKenney
2018-04-07 23:37           ` Paul E. McKenney
2018-04-09 10:58         ` Will Deacon
2018-04-09 10:58           ` Will Deacon
2018-04-07  9:07     ` Peter Zijlstra
2018-04-07  9:07       ` Peter Zijlstra
2018-04-09 10:58     ` Will Deacon
2018-04-09 10:58       ` Will Deacon
2018-04-09 14:54       ` Will Deacon
2018-04-09 14:54         ` Will Deacon
2018-04-09 15:54         ` Peter Zijlstra
2018-04-09 15:54           ` Peter Zijlstra
2018-04-09 17:19           ` Will Deacon
2018-04-09 17:19             ` Will Deacon
2018-04-10  9:35             ` Peter Zijlstra
2018-04-10  9:35               ` Peter Zijlstra
2018-09-20 16:08             ` Peter Zijlstra
2018-09-20 16:08               ` Peter Zijlstra
2018-09-20 16:22               ` Peter Zijlstra
2018-09-20 16:22                 ` Peter Zijlstra
2018-04-09 19:33         ` Waiman Long
2018-04-09 19:33           ` Waiman Long
2018-04-09 17:55       ` Waiman Long
2018-04-09 17:55         ` Waiman Long
2018-04-10 13:49   ` Sasha Levin
2018-04-10 13:49     ` Sasha Levin
2018-04-05 16:59 ` [PATCH 03/10] locking/qspinlock: Kill cmpxchg loop when claiming lock from head of queue Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 17:19   ` Peter Zijlstra
2018-04-05 17:19     ` Peter Zijlstra
2018-04-06 10:54     ` Will Deacon
2018-04-06 10:54       ` Will Deacon
2018-04-05 16:59 ` [PATCH 04/10] locking/qspinlock: Use atomic_cond_read_acquire Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 16:59 ` [PATCH 05/10] locking/mcs: Use smp_cond_load_acquire() in mcs spin loop Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 16:59 ` [PATCH 06/10] barriers: Introduce smp_cond_load_relaxed and atomic_cond_read_relaxed Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 17:22   ` Peter Zijlstra
2018-04-05 17:22     ` Peter Zijlstra
2018-04-06 10:55     ` Will Deacon
2018-04-06 10:55       ` Will Deacon
2018-04-05 16:59 ` [PATCH 07/10] locking/qspinlock: Use smp_cond_load_relaxed to wait for next node Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 16:59 ` [PATCH 08/10] locking/qspinlock: Merge struct __qspinlock into struct qspinlock Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-07  5:23   ` Boqun Feng
2018-04-07  5:23     ` Boqun Feng
2018-04-05 16:59 ` [PATCH 09/10] locking/qspinlock: Make queued_spin_unlock use smp_store_release Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 16:59 ` [PATCH 10/10] locking/qspinlock: Elide back-to-back RELEASE operations with smp_wmb() Will Deacon
2018-04-05 16:59   ` Will Deacon
2018-04-05 17:28   ` Peter Zijlstra [this message]
2018-04-05 17:28     ` Peter Zijlstra
2018-04-06 11:34     ` Will Deacon
2018-04-06 11:34       ` Will Deacon
2018-04-06 13:05       ` Andrea Parri
2018-04-06 13:05         ` Andrea Parri
2018-04-06 15:27         ` Will Deacon
2018-04-06 15:27           ` Will Deacon
2018-04-06 15:49           ` Andrea Parri
2018-04-06 15:49             ` Andrea Parri
2018-04-07  5:47   ` Boqun Feng
2018-04-07  5:47     ` Boqun Feng
2018-04-09 10:47     ` Will Deacon
2018-04-09 10:47       ` Will Deacon
2018-04-06 13:22 ` [PATCH 00/10] kernel/locking: qspinlock improvements Andrea Parri
2018-04-06 13:22   ` Andrea Parri
2018-04-11 10:20   ` Catalin Marinas
2018-04-11 10:20     ` Catalin Marinas
2018-04-11 15:39     ` Andrea Parri
2018-04-11 15:39       ` Andrea Parri

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