[PATCH 0/2 v2] rcu: Fix series of spurious RCU softirqs

From: Frederic Weisbecker <fweisbec@gmail.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH 0/2 v2] rcu: Fix series of spurious RCU softirqs
Date: Fri, 10 Dec 2010 22:11:09 +0100	[thread overview]
Message-ID: <1292015471-19227-1-git-send-email-fweisbec@gmail.com> (raw)

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(-)

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1.7.3.2