On Wed, 17 Jan 2007, Guennadi Liakhovetski wrote:
...as you saw it's with 2.6.18-rc6. Trying to upgrade to 20-rc5-rt3 ATM.
Same problem with 2.6.20-rc5-rt3. Below are relevant code fragments:
The sleeper sleeps on a wait queue::
#define __hrt_wait_event_timeout(wq, condition, ret) \
do { \
DEFINE_WAIT(__wait); \
\
for (;;) { \
prepare_to_wait(&wq, &__wait, TASK_UNINTERRUPTIBLE); \
if (condition) \
break; \
ret = hrt_schedule_timeout_ns(ret); \
if (!ret) \
break; \
} \
finish_wait(&wq, &__wait); \
} while (0)
s64 hrt_schedule_timeout_ns(s64 timeout) // max. 9223372035 seconds (292 years)
{
vdm_hashtable_el_t *he = vdm_hashtable_find(&thread_hash,
(__u32)current);
os_thread_t *thread;
struct hrtimer_sleeper t;
struct timespec now, end;
s64 elapsed;
unsigned long flags;
might_sleep();
if (unlikely(!he)) {
printk(KERN_ERR "%s called from a non-hashed thread!\n",
__FUNCTION__);
WARN_ON(1);
/* Avoid endless loop in hrt_wait_event_timeout() */
return 0;
}
if (unlikely(timeout <= 0)) /* do not wait for moments in the past */
return 0;
thread = he->private;
ktime_get_ts(&now);
spin_lock_irqsave(&thread->lock, flags);
hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
t.timer.expires = ktime_add_ns(timespec_to_ktime(now), timeout);
hrtimer_init_sleeper(&t, current);
thread->sleeper = &t;
hrtimer_start(&t.timer, t.timer.expires, HRTIMER_MODE_ABS);
spin_unlock_irqrestore(&thread->lock, flags);
schedule();
spin_lock_irqsave(&thread->lock, flags);
hrtimer_cancel(&t.timer);
thread->sleeper = NULL;
spin_unlock_irqrestore(&thread->lock, flags);
ktime_get_ts(&end);
elapsed = NSEC_PER_SEC * (s64)(end.tv_sec - now.tv_sec) +
(s64)end.tv_nsec - (s64)now.tv_nsec;
rtpreempt_check_abort();
return elapsed >= timeout ? 0 : timeout - elapsed;
}
And the waker just calls wake_up() on the queue while holding the lock:
spin_lock_irqsave(&sem->lock, flags);
sem->signal++;
wake_up(&sem->wq);
spin_unlock_irqrestore(&sem->lock, flags);
Am I doing anything wrong?
Thanks
Guennadi
---------------------------------
Guennadi Liakhovetski, Ph.D.
DSA Daten- und Systemtechnik GmbH
Pascalstr. 28
D-52076 Aachen
Germany
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