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Message-ID: <20110619085118.GA24512@elte.hu>
Date: Sun, 19 Jun 2011 10:51:18 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] timer fixes
Linus,
Please pull the latest timers-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-urgent-for-linus
Thanks,
Ingo
------------------>
Max Asbock (1):
timerfd: Fix wakeup of processes when timer is cancelled on clock change
Thomas Gleixner (1):
clocksource: Make watchdog robust vs. interruption
fs/timerfd.c | 5 ++++-
include/linux/clocksource.h | 1 +
kernel/time/clocksource.c | 24 +++++++++++++-----------
3 files changed, 18 insertions(+), 12 deletions(-)
diff --git a/fs/timerfd.c b/fs/timerfd.c
index f67acbd..dffeb37 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -61,7 +61,9 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
/*
* Called when the clock was set to cancel the timers in the cancel
- * list.
+ * list. This will wake up processes waiting on these timers. The
+ * wake-up requires ctx->ticks to be non zero, therefore we increment
+ * it before calling wake_up_locked().
*/
void timerfd_clock_was_set(void)
{
@@ -76,6 +78,7 @@ void timerfd_clock_was_set(void)
spin_lock_irqsave(&ctx->wqh.lock, flags);
if (ctx->moffs.tv64 != moffs.tv64) {
ctx->moffs.tv64 = KTIME_MAX;
+ ctx->ticks++;
wake_up_locked(&ctx->wqh);
}
spin_unlock_irqrestore(&ctx->wqh.lock, flags);
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index d4646b4..18a1baf 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -188,6 +188,7 @@ struct clocksource {
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
/* Watchdog related data, used by the framework */
struct list_head wd_list;
+ cycle_t cs_last;
cycle_t wd_last;
#endif
} ____cacheline_aligned;
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 1c95fd6..e0980f0 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -185,7 +185,6 @@ static struct clocksource *watchdog;
static struct timer_list watchdog_timer;
static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
static DEFINE_SPINLOCK(watchdog_lock);
-static cycle_t watchdog_last;
static int watchdog_running;
static int clocksource_watchdog_kthread(void *data);
@@ -254,11 +253,6 @@ static void clocksource_watchdog(unsigned long data)
if (!watchdog_running)
goto out;
- wdnow = watchdog->read(watchdog);
- wd_nsec = clocksource_cyc2ns((wdnow - watchdog_last) & watchdog->mask,
- watchdog->mult, watchdog->shift);
- watchdog_last = wdnow;
-
list_for_each_entry(cs, &watchdog_list, wd_list) {
/* Clocksource already marked unstable? */
@@ -268,19 +262,28 @@ static void clocksource_watchdog(unsigned long data)
continue;
}
+ local_irq_disable();
csnow = cs->read(cs);
+ wdnow = watchdog->read(watchdog);
+ local_irq_enable();
/* Clocksource initialized ? */
if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
cs->flags |= CLOCK_SOURCE_WATCHDOG;
- cs->wd_last = csnow;
+ cs->wd_last = wdnow;
+ cs->cs_last = csnow;
continue;
}
- /* Check the deviation from the watchdog clocksource. */
- cs_nsec = clocksource_cyc2ns((csnow - cs->wd_last) &
+ wd_nsec = clocksource_cyc2ns((wdnow - cs->wd_last) & watchdog->mask,
+ watchdog->mult, watchdog->shift);
+
+ cs_nsec = clocksource_cyc2ns((csnow - cs->cs_last) &
cs->mask, cs->mult, cs->shift);
- cs->wd_last = csnow;
+ cs->cs_last = csnow;
+ cs->wd_last = wdnow;
+
+ /* Check the deviation from the watchdog clocksource. */
if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
clocksource_unstable(cs, cs_nsec - wd_nsec);
continue;
@@ -318,7 +321,6 @@ static inline void clocksource_start_watchdog(void)
return;
init_timer(&watchdog_timer);
watchdog_timer.function = clocksource_watchdog;
- watchdog_last = watchdog->read(watchdog);
watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask));
watchdog_running = 1;
--
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