| From: Julia Cartwright <julia@ni.com> |
| Date: Wed, 12 Oct 2016 11:21:14 -0500 |
| Subject: [PATCH] rcu: enable rcu_normal_after_boot by default for RT |
| |
| The forcing of an expedited grace period is an expensive and very |
| RT-application unfriendly operation, as it forcibly preempts all running |
| tasks on CPUs which are preventing the gp from expiring. |
| |
| By default, as a policy decision, disable the expediting of grace |
| periods (after boot) on configurations which enable PREEMPT_RT. |
| |
| Suggested-by: Luiz Capitulino <lcapitulino@redhat.com> |
| Acked-by: Paul E. McKenney <paulmck@linux.ibm.com> |
| Signed-off-by: Julia Cartwright <julia@ni.com> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| kernel/rcu/update.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/kernel/rcu/update.c |
| +++ b/kernel/rcu/update.c |
| @@ -54,8 +54,10 @@ |
| #ifndef CONFIG_TINY_RCU |
| module_param(rcu_expedited, int, 0); |
| module_param(rcu_normal, int, 0); |
| -static int rcu_normal_after_boot; |
| +static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT); |
| +#ifndef CONFIG_PREEMPT_RT |
| module_param(rcu_normal_after_boot, int, 0); |
| +#endif |
| #endif /* #ifndef CONFIG_TINY_RCU */ |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
