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From: Josh Triplett <josh@joshtriplett.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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 16:48:29 -0800	[thread overview]
Message-ID: <20120202004828.GC29058@leaf> (raw)
In-Reply-To: <20120202004253.GA10946@linux.vnet.ibm.com>

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...

- Josh Triplett

  parent reply	other threads:[~2012-02-02  0:48 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 ` Josh Triplett [this message]
2012-02-02  1:14   ` [PATCH RFC idle] Make arm, sh, and x86 stop using RCU when idle Paul E. McKenney
2012-02-02  2:29 ` Paul Mundt
2012-02-02  4:58   ` Paul E. McKenney

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