Date: Thu, 16 Aug 2007 16:16:49 -0400
From: Dave Jones <davej@redhat.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: khvcd
Message-ID: <20070816201649.GA5375@redhat.com>
Mail-Followup-To: Dave Jones <davej@redhat.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Linux Kernel <linux-kernel@vger.kernel.org>
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Hi Rusty,
 In profiling bootup time, we noticed something new appeared
on the graph at http://pjones.fedorapeople.org/bootchart-preinit.png
in the name of khvcd.

"wtf is this" was my first reaction.
Followed shortly by much headscratching after finding it's
created by drivers/char/hvc_console.c whose Kconfig yeilds..

config HVC_DRIVER
        bool
        help
          Users of pSeries machines that want to utilize the hvc console front-end
          module for their backend console driver should select this option.

Which is a little confusing for those of us not actually using a pSeries.
The above profile came from a x86 box.
A little more grepping around revealed that lguest select's HVC_DRIVER,
thus sneaking this config option into the build.

asides from the needed Kconfig clarification, is it necessary for khvcd
to run at all if the lguest module hasn't been loaded ?  Is it possible
we can somehow delay creation of the kthread ?

	Dave

-- 
http://www.codemonkey.org.uk
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