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 for CONFIG_RCU_NOCB_CPU=n
kernel, the rcu_nocb_cpu_offload/deoffload() is a no-op and this is also
meaningless for torture_type is non-rcu.
This commit therefore add member can_nocbs_toggle to rcu_torture_ops
structure to avoid unnecessary nocb tasks creation.
Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx>
---
kernel/rcu/rcutorture.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 297da28ce92d..ced0a8e1d765 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -383,6 +383,7 @@ struct rcu_torture_ops {
long cbflood_max;
int irq_capable;
int can_boost;
+ int can_nocbs_toggle;
int extendables;
int slow_gps;
int no_pi_lock;
@@ -569,6 +570,7 @@ static struct rcu_torture_ops rcu_ops = {
.stall_dur = rcu_jiffies_till_stall_check,
.irq_capable = 1,
.can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
+ .can_nocbs_toggle = IS_ENABLED(CONFIG_RCU_NOCB_CPU),
.extendables = RCUTORTURE_MAX_EXTEND,
.name = "rcu"
};
@@ -2356,7 +2358,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
"n_barrier_cbs=%d "
"onoff_interval=%d onoff_holdoff=%d "
"read_exit_delay=%d read_exit_burst=%d "
- "nocbs_nthreads=%d nocbs_toggle=%d "
+ "nocbs_nthreads=%d/%d nocbs_toggle=%d "
"test_nmis=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
@@ -2368,7 +2370,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
n_barrier_cbs,
onoff_interval, onoff_holdoff,
read_exit_delay, read_exit_burst,
- nocbs_nthreads, nocbs_toggle,
+ nocbs_nthreads, cur_ops->can_nocbs_toggle, nocbs_toggle,
test_nmis);
}
@@ -3708,6 +3710,10 @@ rcu_torture_init(void)
pr_alert("rcu-torture: ->fqs NULL and non-zero fqs_duration, fqs disabled.\n");
fqs_duration = 0;
}
+ if (!cur_ops->can_nocbs_toggle && nocbs_nthreads != 0) {
+ pr_alert("rcu-torture: ->can_nocbs_toggle false and non-zero nocbs_nthreads, nocbs_toggle disabled.\n");
+ nocbs_nthreads = 0;
+ }
if (cur_ops->init)
cur_ops->init();
--
2.25.1
