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 <fweis...@gmail.com>
---
 init/Kconfig |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index c26b8a1..89093e1 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
-- 
1.7.5.4

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