rcu: Permit RCU_FAST_NO_HZ to be used by TREE_PREEMPT_RCU

The new implementation of RCU_FAST_NO_HZ is compatible with preemptible
RCU, so this commit removes the Kconfig restriction that previously
prohibited this.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --git a/init/Kconfig b/init/Kconfig
index 43298f9..82b6a4c 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -469,14 +469,14 @@ config RCU_FANOUT_EXACT
 
 config RCU_FAST_NO_HZ
        bool "Accelerate last non-dyntick-idle CPU's grace periods"
-       depends on TREE_RCU && NO_HZ && SMP
+       depends on NO_HZ && SMP
        default n
        help
          This option causes RCU to attempt to accelerate grace periods
-         in order to allow the final CPU 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.
+         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.