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authorFrederic Weisbecker <fweisbec@gmail.com>2012-10-11 01:48:28 +0200
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-10-10 17:35:01 -0700
commitd677124b1fc3b2706a13e92f1b329f1ac77e5f20 (patch)
tree8068ec66f9adfb2ce982b627b16226c3cff23036 /init
parenta4fbe35a124526e6759be07bd9c7ea796ba1e00d (diff)
downloadlinaro-lsk-d677124b1fc3b2706a13e92f1b329f1ac77e5f20.tar.gz
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 <fweisbec@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig12
1 files changed, 12 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index c26b8a1d2b5..89093e178c2 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