Now that RCU scans both running tasks and tasks that have blocked within
their current RCU Tasks Trace read-side critical section, there is no
need for it to scan the idle tasks. After all, an idle loop should not
be remain within an RCU Tasks Trace read-side critical section across
exit from idle, and from a BPF viewpoint, functions invoked from the
idle loop should not sleep. So only running idle tasks can be within
RCU Tasks Trace read-side critical sections.
This commit therefore removes the scan of the idle tasks from the
rcu_tasks_trace_postscan() function.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Neeraj Upadhyay <quic_neeraju@xxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andrii Nakryiko <andrii@xxxxxxxxxx>
Cc: Martin KaFai Lau <kafai@xxxxxx>
Cc: KP Singh <kpsingh@xxxxxxxxxx>
---
kernel/rcu/tasks.h | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index d318cdfd2309c..272c905995e56 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1533,16 +1533,10 @@ static void rcu_tasks_trace_pregp_step(struct list_head *hop)
}
/*
- * Do intermediate processing between task and holdout scans and
- * pick up the idle tasks.
+ * Do intermediate processing between task and holdout scans.
*/
static void rcu_tasks_trace_postscan(struct list_head *hop)
{
- int cpu;
-
- for_each_online_cpu(cpu)
- rcu_tasks_trace_pertask(idle_task(cpu), hop);
-
// Re-enable CPU hotplug now that the tasklist scan has completed.
cpus_read_unlock();
--
2.31.1.189.g2e36527f23
