From: Julia Cartwright Date: Wed, 12 Oct 2016 11:21:14 -0500 Subject: [PATCH 164/290] rcu: enable rcu_normal_after_boot by default for RT Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=eb935a53cab85b5354d0dea339bdc8c6aacff1ea 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_FULL. Suggested-by: Luiz Capitulino Acked-by: Paul E. McKenney Signed-off-by: Julia Cartwright Signed-off-by: Sebastian Andrzej Siewior --- kernel/rcu/update.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 6ffafb1b1584..16d8dba23329 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -68,7 +68,7 @@ extern int rcu_expedited; /* from sysctl */ module_param(rcu_expedited, int, 0); extern int rcu_normal; /* from sysctl */ module_param(rcu_normal, int, 0); -static int rcu_normal_after_boot; +static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT_FULL); module_param(rcu_normal_after_boot, int, 0); #endif /* #ifndef CONFIG_TINY_RCU */