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Date: Fri, 10 Dec 2010 22:14:42 +0100
From: Frederic Weisbecker <fweisbec@gmail.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 0/2 v2] rcu: Fix series of spurious RCU softirqs
Message-ID: <20101210211439.GA1713@nowhere>
References: <1292015471-19227-1-git-send-email-fweisbec@gmail.com>
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(Adding Lai in Cc, I forgot my script doesn't handle Suggested-by: tags :)

On Fri, Dec 10, 2010 at 10:11:09PM +0100, Frederic Weisbecker wrote:
> Hi,
> 
> Following Lai's idea.
> 
> An example of such series of spurious softirqs:
> 
> http://tglx.de/~fweisbec/trace_rcu_softirq.txt
> 
> In that example, the rcu softirq is raised at every tick
> during 20 secs (was perhaps more, but the trace snapshot happened
> during 20 secs). It happens randomly.
> 
> Ah and it survived several hours of rcutorture (with rcu cpu stall
> detection).
> 
> Thanks.
> 
> Frederic Weisbecker (2):
>   rcu: Stop chasing QS if another CPU did it for us
>   rcu: Keep gpnum and completed fields synchronized
> 
>  kernel/rcutree.c |   17 +++++++++++++++++
>  1 files changed, 17 insertions(+), 0 deletions(-)
> 
> -- 
> 1.7.3.2
>