From: Zqiang qiang1.zhang@intel.com
Given a non-zero rcutorture.nocbs_nthreads module parameter, the specified number of nocb kthreads will be created, regardless of whether or not the RCU implementation under test is capable of offloading callbacks. Please note that even vanilla RCU is incapable of offloading in kernels built with CONFIG_RCU_NOCB_CPU=n. And when the RCU implementation is incapable of offloading callbacks, there is no point in creating those kthreads.
This commit therefore checks the cur_ops.torture_type module parameter and CONFIG_RCU_NOCB_CPU Kconfig option in order to avoid creating unnecessary nocb tasks.
Signed-off-by: Zqiang qiang1.zhang@intel.com Reviewed-by: Joel Fernandes (Google) joel@joelfernandes.org Signed-off-by: Paul E. McKenney paulmck@kernel.org Signed-off-by: Boqun Feng boqun.feng@gmail.com --- kernel/rcu/rcutorture.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index c0b2fd687bbb..2d1c7e15cd72 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -3525,6 +3525,12 @@ 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();