rcu: Awaken grace-period kthread if too long since FQS
Recent kernels can fail to awaken the grace-period kthread for
quiescent-state forcing. This commit is a crude hack that does
a wakeup if a scheduling-clock interrupt sees that it has been
too long since force-quiescent-state (FQS) processing.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index df668c0..34d3973 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -513,6 +513,8 @@
unsigned long jiffies_force_qs; /* Time at which to invoke */
/* force_quiescent_state(). */
+ unsigned long jiffies_kick_kthreads; /* Time at which to kick */
+ /* kthreads, if configured. */
unsigned long n_force_qs; /* Number of calls to */
/* force_quiescent_state(). */
unsigned long n_force_qs_lh; /* ~Number of calls leaving */