When setting nocbs_nthreads to start rcutorture test with a non-zero value,
the nocb tasks will be created and invoke rcu_nocb_cpu_offload/deoffload()
to toggle CPU's callback-offload state, but this is meaningless for non-rcu
testing or CONFIG_RCU_NOCB_CPU=n kernel create nocb tasks to periodically
toggle CPU's callback-offload state and adds unnecessary testing overhead.
This commit therefore add checks for cur_ops types and CONFIG_RCU_NOCB_CPU
options when nocbs_nthreads is non-zero to avoid unnecessary nocb task
creation.
Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
---
kernel/rcu/rcutorture.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 297da28ce92d..d01127e0e8cd 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -3708,6 +3708,12 @@ rcu_torture_init(void)
pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
fqs_duration = 0;
}
+ if (nocbs_nthreads != 0 && (cur_ops != &rcu_ops ||
+ !IS_ENABLED(CONFIG_RCU_NOCB_CPU))) {
+ pr_alert("rcu-torture types: %s and CONFIG_RCU_NOCB_CPU=%d, nocb toggle disabled.\n",
+ cur_ops->name, IS_ENABLED(CONFIG_RCU_NOCB_CPU));
+ nocbs_nthreads = 0;
+ }
if (cur_ops->init)
cur_ops->init();
--
2.25.1
