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Message-ID: <20100326153423.GA4044@elte.hu>
Date: Fri, 26 Mar 2010 16:34:23 +0100
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-fixes-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
Thanks,
Ingo
------------------>
Andrew Morton (1):
timer stats: Fix del_timer_sync() and try_to_del_timer_sync()
John Stultz (1):
time: Fix accumulation bug triggered by long delay.
Stanislaw Gruszka (1):
posix-cpu-timers: Reset expire cache when no timer is running
Thomas Gleixner (1):
clockevents: Sanitize min_delta_ns adjustment and prevent overflows
include/linux/clockchips.h | 2 +
kernel/posix-cpu-timers.c | 10 ++++++--
kernel/time/tick-oneshot.c | 52 +++++++++++++++++++++++++++++++++----------
kernel/time/timekeeping.c | 3 +-
kernel/time/timer_list.c | 3 +-
kernel/timer.c | 1 +
6 files changed, 54 insertions(+), 17 deletions(-)
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 0cf725b..fc53492 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -73,6 +73,7 @@ enum clock_event_nofitiers {
* @list: list head for the management code
* @mode: operating mode assigned by the management code
* @next_event: local storage for the next event in oneshot mode
+ * @retries: number of forced programming retries
*/
struct clock_event_device {
const char *name;
@@ -93,6 +94,7 @@ struct clock_event_device {
struct list_head list;
enum clock_event_mode mode;
ktime_t next_event;
+ unsigned long retries;
};
/*
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 438ff45..edec25a 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1060,9 +1060,9 @@ static void check_thread_timers(struct task_struct *tsk,
}
}
-static void stop_process_timers(struct task_struct *tsk)
+static void stop_process_timers(struct signal_struct *sig)
{
- struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+ struct thread_group_cputimer *cputimer = &sig->cputimer;
unsigned long flags;
if (!cputimer->running)
@@ -1071,6 +1071,10 @@ static void stop_process_timers(struct task_struct *tsk)
spin_lock_irqsave(&cputimer->lock, flags);
cputimer->running = 0;
spin_unlock_irqrestore(&cputimer->lock, flags);
+
+ sig->cputime_expires.prof_exp = cputime_zero;
+ sig->cputime_expires.virt_exp = cputime_zero;
+ sig->cputime_expires.sched_exp = 0;
}
static u32 onecputick;
@@ -1131,7 +1135,7 @@ static void check_process_timers(struct task_struct *tsk,
list_empty(&timers[CPUCLOCK_VIRT]) &&
cputime_eq(sig->it[CPUCLOCK_VIRT].expires, cputime_zero) &&
list_empty(&timers[CPUCLOCK_SCHED])) {
- stop_process_timers(tsk);
+ stop_process_timers(sig);
return;
}
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 0a8a213..aada0e5 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -22,6 +22,29 @@
#include "tick-internal.h"
+/* Limit min_delta to a jiffie */
+#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
+
+static int tick_increase_min_delta(struct clock_event_device *dev)
+{
+ /* Nothing to do if we already reached the limit */
+ if (dev->min_delta_ns >= MIN_DELTA_LIMIT)
+ return -ETIME;
+
+ if (dev->min_delta_ns < 5000)
+ dev->min_delta_ns = 5000;
+ else
+ dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+ if (dev->min_delta_ns > MIN_DELTA_LIMIT)
+ dev->min_delta_ns = MIN_DELTA_LIMIT;
+
+ printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
+ dev->name ? dev->name : "?",
+ (unsigned long long) dev->min_delta_ns);
+ return 0;
+}
+
/**
* tick_program_event internal worker function
*/
@@ -37,23 +60,28 @@ int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
if (!ret || !force)
return ret;
+ dev->retries++;
/*
- * We tried 2 times to program the device with the given
- * min_delta_ns. If that's not working then we double it
+ * We tried 3 times to program the device with the given
+ * min_delta_ns. If that's not working then we increase it
* and emit a warning.
*/
if (++i > 2) {
/* Increase the min. delta and try again */
- if (!dev->min_delta_ns)
- dev->min_delta_ns = 5000;
- else
- dev->min_delta_ns += dev->min_delta_ns >> 1;
-
- printk(KERN_WARNING
- "CE: %s increasing min_delta_ns to %llu nsec\n",
- dev->name ? dev->name : "?",
- (unsigned long long) dev->min_delta_ns << 1);
-
+ if (tick_increase_min_delta(dev)) {
+ /*
+ * Get out of the loop if min_delta_ns
+ * hit the limit already. That's
+ * better than staying here forever.
+ *
+ * We clear next_event so we have a
+ * chance that the box survives.
+ */
+ printk(KERN_WARNING
+ "CE: Reprogramming failure. Giving up\n");
+ dev->next_event.tv64 = KTIME_MAX;
+ return -ETIME;
+ }
i = 0;
}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 1673637..39f6177 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -818,7 +818,8 @@ void update_wall_time(void)
shift = min(shift, maxshift);
while (offset >= timekeeper.cycle_interval) {
offset = logarithmic_accumulation(offset, shift);
- shift--;
+ if(offset < timekeeper.cycle_interval<<shift)
+ shift--;
}
/* correct the clock when NTP error is too big */
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index bdfb8dd..1a4a7dd 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -228,6 +228,7 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
SEQ_printf(m, " event_handler: ");
print_name_offset(m, dev->event_handler);
SEQ_printf(m, "\n");
+ SEQ_printf(m, " retries: %lu\n", dev->retries);
}
static void timer_list_show_tickdevices(struct seq_file *m)
@@ -257,7 +258,7 @@ static int timer_list_show(struct seq_file *m, void *v)
u64 now = ktime_to_ns(ktime_get());
int cpu;
- SEQ_printf(m, "Timer List Version: v0.5\n");
+ SEQ_printf(m, "Timer List Version: v0.6\n");
SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
diff --git a/kernel/timer.c b/kernel/timer.c
index c61a794..fc965ea 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -880,6 +880,7 @@ int try_to_del_timer_sync(struct timer_list *timer)
if (base->running_timer == timer)
goto out;
+ timer_stats_timer_clear_start_info(timer);
ret = 0;
if (timer_pending(timer)) {
detach_timer(timer, 1);
--
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