[RFC][patch 05/12] clocksource watchdog resume logic

Martin Schwidefsky
2009-07-29T13:43:51Z

[-- Attachment #1: watchdog-resume.diff --]
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From: Martin Schwidefsky <schwidefsky@de.ibm.com>

To resume the clocksource watchdog just remove the CLOCK_SOURCE_WATCHDOG
bit from the watched clocksource.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
kernel/time/clocksource.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)

Index: linux-2.6/kernel/time/clocksource.c
===================================================================
--- linux-2.6.orig/kernel/time/clocksource.c
+++ linux-2.6/kernel/time/clocksource.c
@@ -145,7 +145,6 @@ static struct clocksource *watchdog;
static struct timer_list watchdog_timer;
static DEFINE_SPINLOCK(watchdog_lock);
static cycle_t watchdog_last;
-static unsigned long watchdog_resumed;

/*
* Interval: 0.5sec Threshold: 0.0625s
@@ -167,12 +166,9 @@ static void clocksource_watchdog(unsigne
struct clocksource *cs, *tmp;
cycle_t csnow, wdnow;
int64_t wd_nsec, cs_nsec;
- int resumed;

spin_lock(&watchdog_lock);

- resumed = test_and_clear_bit(0, &watchdog_resumed);
-
wdnow = watchdog->read(watchdog);
wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
watchdog_last = wdnow;
@@ -223,14 +219,26 @@ static void clocksource_watchdog(unsigne
}
spin_unlock(&watchdog_lock);
}
+
+static inline void clocksource_reset_watchdog(void)
+{
+ struct clocksource *cs;
+
+ list_for_each_entry(cs, &watchdog_list, wd_list)
+ cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
+}
+
static void clocksource_resume_watchdog(void)
{
- set_bit(0, &watchdog_resumed);
+ unsigned long flags;
+
+ spin_lock_irqsave(&watchdog_lock, flags);
+ clocksource_reset_watchdog();
+ spin_unlock_irqrestore(&watchdog_lock, flags);
}

static void clocksource_check_watchdog(struct clocksource *cs)
{
- struct clocksource *cse;
unsigned long flags;

spin_lock_irqsave(&watchdog_lock, flags);
@@ -256,8 +264,7 @@ static void clocksource_check_watchdog(s
watchdog_timer.function = clocksource_watchdog;

/* Reset watchdog cycles */
- list_for_each_entry(cse, &watchdog_list, wd_list)
- cse->flags &= ~CLOCK_SOURCE_WATCHDOG;
+ clocksource_reset_watchdog();
/* Start if list is not empty */
if (!list_empty(&watchdog_list)) {
watchdog_last = watchdog->read(watchdog);