From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Josh Triplett <josh@joshtriplett.org>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, Valdis.Kletnieks@vt.edu,
dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com,
fweisbec@gmail.com, patches@linaro.org
Subject: Re: [PATCH RFC idle] Make arm, sh, and x86 stop using RCU when idle
Date: Wed, 1 Feb 2012 17:14:47 -0800 [thread overview]
Message-ID: <20120202011447.GS2382@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120202004828.GC29058@leaf>
On Wed, Feb 01, 2012 at 04:48:29PM -0800, Josh Triplett wrote:
> On Wed, Feb 01, 2012 at 04:42:53PM -0800, Paul E. McKenney wrote:
> > RCU's shiny new diagnostics (thank you, Frederic!) for using RCU when idle
> > located a few problems in arm, sh, and x86. This patch series contains
> > alleged fixes for these problems. And they are real problems -- if RCU
> > believes that the CPU is idle, it is ignoring it. Which means that the
> > idle CPU can say "rcu_read_lock()" all it like, but there will be no
> > useful effect.
>
> Having to put these calls down in every idle driver seems like such an
> ugly layering violation. Not that I have a better alternative to
> suggest...
If you do happen to think of one, I would very much like to hear of it! ;-)
Thanx, Paul
next prev parent reply other threads:[~2012-02-02 1:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-02 0:42 [PATCH RFC idle] Make arm, sh, and x86 stop using RCU when idle Paul E. McKenney
2012-02-02 0:43 ` [PATCH RFC idle 1/3] x86: Avoid invoking RCU when CPU is idle Paul E. McKenney
2012-02-02 0:43 ` [PATCH RFC idle 3/3] sh: " Paul E. McKenney
2012-02-02 1:54 ` [PATCH RFC idle 1/3] x86: " Frederic Weisbecker
2012-02-02 4:55 ` Paul E. McKenney
2012-02-02 0:48 ` [PATCH RFC idle] Make arm, sh, and x86 stop using RCU when idle Josh Triplett
2012-02-02 1:14 ` Paul E. McKenney [this message]
2012-02-02 2:29 ` Paul Mundt
2012-02-02 4:58 ` Paul E. McKenney
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