diff options
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-04-21 09:22:14 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-05-27 12:59:06 -0700
commit26730f55c2842b4ee06a5307d58265db7dd26065 (patch)
parentrcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT_LEAF (diff)
rcu: Make RCU able to tolerate undefined CONFIG_RCU_KTHREAD_PRIO
This commit updates the initialization of the kthread_prio boot parameter so that RCU will build even when CONFIG_RCU_KTHREAD_PRIO is undefined. The kthread_prio boot parameter is set to CONFIG_RCU_KTHREAD_PRIO if that is defined, otherwise to 1 if CONFIG_RCU_BOOST is defined and to zero otherwise. This commit then makes CONFIG_RCU_KTHREAD_PRIO depend on CONFIG_RCU_EXPERT, so that Kconfig users won't be asked about CONFIG_RCU_KTHREAD_PRIO unless they want to be. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
2 files changed, 5 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 78176001f73b..af2c93c4a105 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -671,6 +671,7 @@ config RCU_KTHREAD_PRIO
range 0 99 if !RCU_BOOST
default 1 if RCU_BOOST
default 0 if !RCU_BOOST
+ depends on RCU_EXPERT
This option specifies the SCHED_FIFO priority value that will be
assigned to the rcuc/n and rcub/n threads and is also the value
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1edd11298224..0e9ce1272971 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -165,7 +165,11 @@ static void invoke_rcu_core(void);
static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp);
/* rcuc/rcub kthread realtime priority */
static int kthread_prio = CONFIG_RCU_KTHREAD_PRIO;
+#else /* #ifdef CONFIG_RCU_KTHREAD_PRIO */
+static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0;
+#endif /* #else #ifdef CONFIG_RCU_KTHREAD_PRIO */
module_param(kthread_prio, int, 0644);
/* Delay in jiffies for grace-period initialization delays, debug only. */