From: Davidlohr Bueso <dave@stgolabs.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, George Spelvin <linux@horizon.com>,
Thomas Gleixner <tglx@linutronix.de>,
Manfred Spraul <manfred@colorfullife.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2] ipc/msg: Implement lockless pipelined wakeups
Date: Wed, 4 Nov 2015 09:32:17 -0800 [thread overview]
Message-ID: <20151104173217.GA15994@linux-uzut.site> (raw)
In-Reply-To: <20151104115538.GK17308@twins.programming.kicks-ass.net>
On Wed, 04 Nov 2015, Peter Zijlstra wrote:
>On Tue, Nov 03, 2015 at 04:03:29PM +0100, Sebastian Andrzej Siewior wrote:
>
>> - struct msg_msg *volatile r_msg;
>> + struct msg_msg *r_msg;
>
>> + wake_q_add(wake_q, msr->r_tsk);
>> msr->r_msg = msg;
>> + /*
>> + * Rely on the implicit cmpxchg barrier from
>> + * wake_q_add such that we can ensure that
>
>Davidlohr, didn't you want to make that cmpxchg_relaxed() or
>cmpxchg_release() ?
Right, I had forgotten about that. iirc we ended up deciding to fully
relax the cmpxchg and update the callers instead.
next prev parent reply other threads:[~2015-11-04 17:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-03 15:03 [PATCH v2] ipc/msg: Implement lockless pipelined wakeups Sebastian Andrzej Siewior
2015-11-03 17:30 ` Davidlohr Bueso
2015-11-03 20:12 ` Sebastian Andrzej Siewior
2015-11-04 18:11 ` Davidlohr Bueso
2015-11-04 11:55 ` Peter Zijlstra
2015-11-04 17:32 ` Davidlohr Bueso [this message]
2015-11-04 12:02 ` Peter Zijlstra
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