[PATCH -mm] fix jiffies clocksource inittime

From: john stultz
Date: Wed Apr 04 2007 - 15:50:54 EST


Andrew,
In debugging a problem w/ the -rt tree, I noticed that on systems that
mark the tsc as unstable before it is registered, the TSC would still be
selected and used for a short period of time. Digging in it looks to be
a result of the mix of the clocksource list changes and my clocksource
initialization changes.

With the -rt tree, using a bad TSC, even for a short period of time can
results in a hang at boot. I was not able to reproduce this hang w/
mainline, but I'm not completely certain that someone won't trip on it.

This patch resolves the issue by initializing the jiffies clocksource
earlier so a bad TSC won't get selected just because nothing else is yet
registered.

thanks
-john

Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>

diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index 3be8da8..4c256fd 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -69,4 +69,4 @@ static int __init init_jiffies_clocksour
return clocksource_register(&clocksource_jiffies);
}

-module_init(init_jiffies_clocksource);
+core_initcall(init_jiffies_clocksource);


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