[PATCH tip/core/rcu 18/27] rcu: Add comment to the last sleep in the rcu tasks loop

Paul E. McKenney
2018-06-26T00:35:04Z

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

At the end of rcu_tasks_kthread() there's a lonely
schedule_timeout_uninterruptible() call with no apparent rationale for
its existence. But there is. It is to keep the thread from going into
a tight loop if there's some anomaly. That really needs a comment.

Link: http://lkml.kernel.org/r/20180524223839.GU3803@linux.vnet.ibm.com
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcu/update.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 4c7c49c106ee..39cb23d22109 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -814,6 +814,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
list = next;
cond_resched();
}
+ /* Paranoid sleep to keep this from entering a tight loop */
schedule_timeout_uninterruptible(HZ/10);
}
}
--
2.17.1