From: Peter Zijlstra <peterz@infradead.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Manfred Spraul <manfred@colorfullife.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Susanne Spraul <1vier1@web.de>,
parri.andrea@gmail.com
Subject: Re: spin_lock implicit/explicit memory barrier
Date: Fri, 19 Aug 2016 16:01:06 +0200 [thread overview]
Message-ID: <20160819140106.GJ10121@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160812025946.GA6290@tardis.cn.ibm.com>
On Fri, Aug 12, 2016 at 10:59:46AM +0800, Boqun Feng wrote:
> But if an arch implements its spin_lock() with a full barrier, even
> though the atomic is implemented by ll/sc, the STORE part of which can't
> be reordered with memory operations in the critcal sections. I think
> maybe that's the case for alpha(and also for ARM32).
Correct, Alpha only has a full fence and uses that after the ll/sc to
provide acquire semantics, ARM has other barriers but too uses a full
barrier here.
next prev parent reply other threads:[~2016-08-19 14:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-09 18:52 Manfred Spraul
2016-08-10 0:05 ` Benjamin Herrenschmidt
2016-08-10 18:21 ` Manfred Spraul
2016-08-10 19:17 ` Davidlohr Bueso
2016-08-10 21:00 ` Paul E. McKenney
2016-08-15 20:06 ` Manfred Spraul
2016-08-15 20:28 ` Paul E. McKenney
2016-08-12 2:47 ` Boqun Feng
2016-08-12 18:43 ` Manfred Spraul
2016-08-22 9:15 ` Boqun Feng
2016-08-10 20:52 ` Paul E. McKenney
2016-08-10 22:23 ` Davidlohr Bueso
2016-08-10 22:58 ` Paul E. McKenney
2016-08-10 23:29 ` Davidlohr Bueso
2016-08-11 8:11 ` Peter Zijlstra
2016-08-11 18:31 ` Davidlohr Bueso
2016-08-12 2:59 ` Boqun Feng
2016-08-19 14:01 ` Peter Zijlstra [this message]
2016-08-10 23:59 ` Benjamin Herrenschmidt
2016-08-10 18:33 ` Paul E. McKenney
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