From 9fc52d832b5e7f6e175f3b20ae94504b780b9fd3 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 8 Jan 2013 15:48:33 -0800 Subject: [PATCH] rcu: Allow TREE_PREEMPT_RCU on UP systems The TINY_PREEMPT_RCU is complex, does not provide that much memory savings, and therefore TREE_PREEMPT_RCU should be used instead. The systems where the difference between TINY_PREEMPT_RCU and TREE_PREEMPT_RCU are quite small compared to the memory footprint of CONFIG_PREEMPT. This commit therefore takes a first step towards eliminating TINY_PREEMPT_RCU by allowing TREE_PREEMPT_RCU to be configured on !SMP systems. Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- init/Kconfig | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index a5e90e139ba5..fb19b46c0042 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -453,7 +453,7 @@ config TREE_RCU config TREE_PREEMPT_RCU bool "Preemptible tree-based hierarchical RCU" - depends on PREEMPT && SMP + depends on PREEMPT help This option selects the RCU implementation that is designed for very large SMP systems with hundreds or @@ -461,6 +461,8 @@ config TREE_PREEMPT_RCU is also required. It also scales down nicely to smaller systems. + Select this option if you are unsure. + config TINY_RCU bool "UP-only small-memory-footprint RCU" depends on !PREEMPT && !SMP