From d677124b1fc3b2706a13e92f1b329f1ac77e5f20 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 11 Oct 2012 01:48:28 +0200 Subject: rcu: Advise most users not to enable RCU user mode Discourage distros from enabling CONFIG_RCU_USER_QS because it brings overhead for no benefits yet. It's not a useful feature on its own until we can fully run an adaptive tickless kernel. Signed-off-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney --- init/Kconfig | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index c26b8a1d2b57..89093e178c27 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -451,6 +451,12 @@ config RCU_USER_QS excluded from the global RCU state machine and thus doesn't to keep the timer tick on for RCU. + Unless you want to hack and help the development of the full + tickless feature, you shouldn't enable this option. It adds + unnecessary overhead. + + If unsure say N + config RCU_USER_QS_FORCE bool "Force userspace extended QS by default" depends on RCU_USER_QS @@ -459,6 +465,12 @@ config RCU_USER_QS_FORCE test this feature that treats userspace as an extended quiescent state until we have a real user like a full adaptive nohz option. + Unless you want to hack and help the development of the full + tickless feature, you shouldn't enable this option. It adds + unnecessary overhead. + + If unsure say N + config RCU_FANOUT int "Tree-based hierarchical RCU fanout value" range 2 64 if 64BIT -- cgit v1.2.3-59-g8ed1b