rcu: Update RCU_FAST_NO_HZ help text

The RCU_FAST_NO_HZ help text included a warning about overhead on large
systems, but that issue has since been resolved.  The main remaining
issue with RCU_FAST_NO_HZ is increased real-time latency.  This commit
therefore updates the help text accordingly.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/init/Kconfig b/init/Kconfig
index 6fdd6e339326a079a2b6b5a3a1d2940b2bd81bd8..b63e7982c1c67e1322bfb1e04655a499f645e0e7 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -582,14 +582,13 @@ config RCU_FAST_NO_HZ
        depends on NO_HZ && SMP
        default n
        help
-         This option causes RCU to attempt to accelerate grace periods
-         in order to allow CPUs to enter dynticks-idle state more
-         quickly.  On the other hand, this option increases the overhead
-         of the dynticks-idle checking, particularly on systems with
-         large numbers of CPUs.
-
-         Say Y if energy efficiency is critically important, particularly
-               if you have relatively few CPUs.
+         This option causes RCU to attempt to accelerate grace periods in
+         order to allow CPUs to enter dynticks-idle state more quickly.
+         On the other hand, this option increases the overhead of the
+         dynticks-idle checking, thus degrading scheduling latency.
+
+         Say Y if energy efficiency is critically important, and you don't
+               care about real-time response.
 
          Say N if you are unsure.