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Date: Fri, 21 Sep 2012 13:31:49 -0700
From: Tony Lindgren <tony@atomide.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Walmsley <paul@pwsan.com>, "Bruce, Becky" <bbruce@ti.com>,
        "Paul E. McKenney" <paul.mckenney@linaro.org>,
        "<linux-kernel@vger.kernel.org>" <linux-kernel@vger.kernel.org>,
        "<linux-omap@vger.kernel.org>" <linux-omap@vger.kernel.org>,
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	<linux-arm-kernel@lists.infradead.org>,
        "Hilman, Kevin" <khilman@ti.com>,
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        "Hunter, Jon" <jon-hunter@ti.com>,
        "<snijsure@grid-net.com>" <snijsure@grid-net.com>, fweisbec@gmail.com
Subject: Re: rcu self-detected stall messages on OMAP3, 4 boards
Message-ID: <20120921203149.GI28835@atomide.com>
References: <20120920000351.GI2455@linux.vnet.ibm.com>
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* Paul E. McKenney <paulmck@linux.vnet.ibm.com> [120921 12:58]:
> 
> Just to make sure I understand the combinations:
> 
> o	All stalls have happened when running a minimal userspace.
> o	CONFIG_NO_HZ=n suppresses the stalls.
> o	CONFIG_RCU_FAST_NO_HZ (which depends on CONFIG_NO_HZ=y) has
> 	no observable effect on the stalls.

The reason why you may need minimal userspace is to cut down
the number of timers waking up the system with NO_HZ.
Booting with init=/bin/sh might also do the trick for that.

Regards,

Tony