the attached patch fixes a race noticed by Mike Galbraith: the scheduler
can lose a rebalance tick if some task happens to not be rescheduled in
time. This is not a fatal condition, but an inconsistency nevertheless.
Ingo
--- linux/kernel/sched.c.orig
+++ linux/kernel/sched.c
@@ -1180,7 +1180,7 @@ void scheduler_tick(int user_ticks, int
/* Task might have expired already, but not scheduled off yet */
if (p->array != rq->active) {
set_tsk_need_resched(p);
- return;
+ goto out;
}
spin_lock(&rq->lock);
/*
@@ -1207,7 +1207,7 @@ void scheduler_tick(int user_ticks, int
dequeue_task(p, rq->active);
enqueue_task(p, rq->active);
}
- goto out;
+ goto out_unlock;
}
if (!--p->time_slice) {
dequeue_task(p, rq->active);
@@ -1223,8 +1223,9 @@ void scheduler_tick(int user_ticks, int
} else
enqueue_task(p, rq->active);
}
-out:
+out_unlock:
spin_unlock(&rq->lock);
+out:
rebalance_tick(rq, 0);
}
-
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This archive was generated by hypermail 2b29 : Fri May 23 2003 - 22:00:33 EST