diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2009-08-14 15:47:22 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2009-08-15 10:55:46 +0200 |
| commit | 8cf4e750f8459d51c2e8a035a201da4bf7aa996a (patch) | |
| tree | b197e6074bae727556cce983c21cfdcf17dc6388 /kernel | |
| parent | clocksource: Cleanup clocksource selection (diff) | |
| download | linux-8cf4e750f8459d51c2e8a035a201da4bf7aa996a.tar.xz linux-8cf4e750f8459d51c2e8a035a201da4bf7aa996a.zip | |
clocksource: Delay clocksource watchdog highres enablement
The clocksource watchdog marks a clock as highres capable before it
checked the deviation from the watchdog clocksource even for a single
time. Make sure that the deviation is at least checked once before
doing the switch to highres mode.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Daniel Walker <dwalker@fifo99.com>
LKML-Reference: <20090814134808.627795883@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/clocksource.c | 47 |
1 files changed, 22 insertions, 25 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index e91662e87cde..76256c5aecb8 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -153,11 +153,8 @@ static unsigned long watchdog_resumed; #define WATCHDOG_INTERVAL (HZ >> 1) #define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4) -static void clocksource_ratewd(struct clocksource *cs, int64_t delta) +static void clocksource_unstable(struct clocksource *cs, int64_t delta) { - if (delta > -WATCHDOG_THRESHOLD && delta < WATCHDOG_THRESHOLD) - return; - printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n", cs->name, delta); cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG); @@ -183,31 +180,31 @@ static void clocksource_watchdog(unsigned long data) list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) { csnow = cs->read(cs); - if (unlikely(resumed)) { + /* Clocksource initialized ? */ + if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) { + cs->flags |= CLOCK_SOURCE_WATCHDOG; cs->wd_last = csnow; continue; } - /* Initialized ? */ - if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) { - if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && - (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) { - cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; - /* - * We just marked the clocksource as - * highres-capable, notify the rest of the - * system as well so that we transition - * into high-res mode: - */ - tick_clock_notify(); - } - cs->flags |= CLOCK_SOURCE_WATCHDOG; - cs->wd_last = csnow; - } else { - cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask); - cs->wd_last = csnow; - /* Check the delta. Might remove from the list ! */ - clocksource_ratewd(cs, cs_nsec - wd_nsec); + /* Check the deviation from the watchdog clocksource. */ + cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask); + cs->wd_last = csnow; + if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) { + clocksource_unstable(cs, cs_nsec - wd_nsec); + continue; + } + + if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) && + (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) && + (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) { + cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES; + /* + * We just marked the clocksource as highres-capable, + * notify the rest of the system as well so that we + * transition into high-res mode: + */ + tick_clock_notify(); } } |