[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date: Thu, 11 Oct 2012 01:48:28 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: "Paul E. McKenney" <paul.mckenney@...aro.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Frederic Weisbecker <fweisbec@...il.com>
Subject: [PATCH] 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@...il.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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists