[patch 4/5] sched: Switch wait_task_inactive to schedule_hrtimeout()

From: Thomas Gleixner
Date: Wed Feb 23 2011 - 18:53:55 EST


When we force thread hard and soft interrupts the startup of ksoftirqd
would hang in kthread_bind() when wait_task_inactive() calls
schedule_timeout_uninterruptible() because there is no softirq yet
which will wake us up.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/sched.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6-tip/kernel/sched.c
===================================================================
--- linux-2.6-tip.orig/kernel/sched.c
+++ linux-2.6-tip/kernel/sched.c
@@ -2224,7 +2224,10 @@ unsigned long wait_task_inactive(struct
* yield - it could be a while.
*/
if (unlikely(on_rq)) {
- schedule_timeout_uninterruptible(1);
+ ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ);
+
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ schedule_hrtimeout(&to, HRTIMER_MODE_REL);
continue;
}



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