Commit 948ac6d7 authored Mar 25, 2007 by Thomas Gleixner Committed by Linus Torvalds Mar 25, 2007

[PATCH] clocksource: Fix thinko in watchdog selection



The watchdog implementation excludes low res / non continuous
clocksources from being selected as a watchdog reference
unintentionally.

Allow using jiffies/PIT as a watchdog reference as long as no better
clocksource is available. This is necessary to detect TSC breakage on
systems, which have no pmtimer/hpet.

The main goal of the initial patch (preventing to switch to highres/nohz
when no reliable fallback clocksource is available) is still guaranteed
by the checks in clocksource_watchdog().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9501b6cf

kernel/time/clocksource.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -151,7 +151,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
		watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
		add_timer(&watchdog_timer);
		}
		} else if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) {
		} else {
		if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
		cs->flags \|= CLOCK_SOURCE_VALID_FOR_HRES;

		if (!watchdog \|\| cs->rating > watchdog->rating) {