[PATCH 12/16] rcu/nocb: Only cond_resched() from actual offloaded batch processing

Frederic Weisbecker
2020-10-23T14:47:55Z

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@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
---
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 6bad7018dc18..35834ce2d042 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2491,8 +2491,7 @@ 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