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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2012-10-11 01:48:28 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-10-10 17:35:01 -0700 |
| commit | d677124b1fc3b2706a13e92f1b329f1ac77e5f20 (patch) | |
| tree | 8068ec66f9adfb2ce982b627b16226c3cff23036 /init | |
| parent | a4fbe35a124526e6759be07bd9c7ea796ba1e00d (diff) | |
| download | lwn-d677124b1fc3b2706a13e92f1b329f1ac77e5f20.tar.gz lwn-d677124b1fc3b2706a13e92f1b329f1ac77e5f20.zip | |
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/Kconfig | 12 |
1 files changed, 12 insertions, 0 deletions
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 |