rcu: increment quiescent state counter in ksoftirqd()
If a machine is flooded by network frames, a cpu can loop
100% of its time inside ksoftirqd() without calling schedule().
This can delay RCU grace period to insane values.
Adding rcu_qsctr_inc() call in ksoftirqd() solves this problem.
Paul: "This regression was a result of the recent change from
"schedule()" to "cond_resched()", which got rid of that quiescent
state in the common case where a reschedule is not needed".
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/softirq.c b/kernel/softirq.c
index bdbe9de..9041ea7 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -626,6 +626,7 @@
preempt_enable_no_resched();
cond_resched();
preempt_disable();
+ rcu_qsctr_inc((long)__bind_cpu);
}
preempt_enable();
set_current_state(TASK_INTERRUPTIBLE);