[PATCH 11/19] rcu/nocb: Only cond_resched() from actual offloaded batch processing

From: Frederic Weisbecker
Date: Fri Nov 13 2020 - 07:14:28 EST


rcu_do_batch() will be callable concurrently by softirqs and offloaded
processing. So make sure we actually call cond resched only from the
offloaded context.

Inspired-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Neeraj Upadhyay <neeraju@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
---
kernel/rcu/tree.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 049433d0fa05..da1ecf60c541 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2510,8 +2510,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
/* Exceeded the time limit, so leave. */
break;
}
- if (offloaded) {
- WARN_ON_ONCE(in_serving_softirq());
+ if (!in_serving_softirq()) {
local_bh_enable();
lockdep_assert_irqs_enabled();
cond_resched_tasks_rcu_qs();
--
2.25.1