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From: Peter Zijlstra <peterz@infradead.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Will Deacon <will@kernel.org>, Boqun Feng <boqun.feng@gmail.com>,
	Ingo Molnar <mingo@redhat.com>, Waiman Long <longman@redhat.com>,
	Anton Blanchard <anton@ozlabs.org>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH 2/8] powerpc/pseries: use smp_rmb() in H_CONFER spin yield
Date: Thu, 2 Jul 2020 10:28:40 +0200	[thread overview]
Message-ID: <20200702082840.GC4781@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200702074839.1057733-3-npiggin@gmail.com>

On Thu, Jul 02, 2020 at 05:48:33PM +1000, Nicholas Piggin wrote:
> There is no need for rmb(), this allows faster lwsync here.

Since you determined this; I'm thinking you actually understand the
ordering here. How about recording this understanding in a comment?

Also, should the lock->slock load not use READ_ONCE() ?


  reply	other threads:[~2020-07-02  8:28 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-02  7:48 [PATCH 0/8] powerpc: queued spinlocks and rwlocks Nicholas Piggin
2020-07-02  7:48 ` [PATCH 1/8] powerpc/powernv: must include hvcall.h to get PAPR defines Nicholas Piggin
2020-07-02  7:48 ` [PATCH 2/8] powerpc/pseries: use smp_rmb() in H_CONFER spin yield Nicholas Piggin
2020-07-02  8:28   ` Peter Zijlstra [this message]
2020-07-02 10:36     ` Nicholas Piggin
2020-07-02  7:48 ` [PATCH 3/8] powerpc/pseries: move some PAPR paravirt functions to their own file Nicholas Piggin
2020-07-02  7:48 ` [PATCH 4/8] powerpc: move spinlock implementation to simple_spinlock Nicholas Piggin
2020-07-02  7:48 ` [PATCH 5/8] powerpc/64s: implement queued spinlocks and rwlocks Nicholas Piggin
2020-07-02  8:02   ` Will Deacon
2020-07-02 10:25     ` Nicholas Piggin
2020-07-02 10:35       ` Will Deacon
2020-07-02 10:47         ` Nicholas Piggin
2020-07-02 10:48           ` Will Deacon
2020-07-03 10:52           ` Michael Ellerman
2020-07-02  7:48 ` [PATCH 6/8] powerpc/pseries: implement paravirt qspinlocks for SPLPAR Nicholas Piggin
2020-07-02 16:15   ` kernel test robot
2020-07-03  0:36     ` Waiman Long
2020-07-02 21:01   ` Waiman Long
2020-07-02  7:48 ` [PATCH 7/8] powerpc/qspinlock: optimised atomic_try_cmpxchg_lock that adds the lock hint Nicholas Piggin
2020-07-02  7:48 ` [PATCH 8/8] powerpc/64s: remove paravirt from simple spinlocks (RFC only) Nicholas Piggin

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