From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Davidlohr Bueso <dave@stgolabs.net>, George Spelvin <linux@horizon.com>
Cc: tglx@linutronix.de, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, manfred@colorfullife.com,
peterz@infradead.org
Subject: Re: [PATCH] ipc/msg: Implement lockless pipelined wakeups
Date: Tue, 3 Nov 2015 15:15:28 +0100 [thread overview]
Message-ID: <5638C180.6050901@linutronix.de> (raw)
In-Reply-To: <20151031190633.GA1707@linux-uzut.site>
On 10/31/2015 08:06 PM, Davidlohr Bueso wrote:
> On Sat, 31 Oct 2015, Bueso wrote:
>
>> Yes, and this confirms that we still rely on the implicit barrier
>> from the cmpxchg as tglx mentioned. As such, we also need to keep
>> the pairing when reading 'r_msg' in do_msgrcv(), instead of dropping
>> the comments.
>
> Hmm having r_msg as volatile seems even less needed now, we should
> drop it. I imagine it was there initially for the busy-wait on the variable
> becoming non-nil, but we had cpu_relax _anyway_, so ...
Didn't noticed that. So that volatile part and the casts are gone, too.
Sebastian
next prev parent reply other threads:[~2015-11-03 14:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-30 11:26 [PATCH] ipc/msg: Implement lockless pipelined wakeups Sebastian Andrzej Siewior
2015-10-30 22:30 ` George Spelvin
2015-11-03 14:01 ` Sebastian Andrzej Siewior
2015-10-31 10:31 ` Thomas Gleixner
2015-10-31 13:02 ` George Spelvin
2015-10-31 15:17 ` Thomas Gleixner
2015-10-31 18:54 ` Davidlohr Bueso
2015-10-31 19:06 ` Davidlohr Bueso
2015-11-03 14:15 ` Sebastian Andrzej Siewior [this message]
2015-11-03 14:11 ` Sebastian Andrzej Siewior
2015-11-01 4:32 ` Manfred Spraul
2015-11-03 14:51 ` Sebastian Andrzej Siewior
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