rcu: restrict TREE_RCU to SMP builds with !PREEMPT

Because both TINY_RCU and TREE_PREEMPT_RCU have been in mainline for
several releases, it is time to restrict the use of TREE_RCU to SMP
non-preemptible systems.  This reduces testing/validation effort.  This
commit is a first step towards driving the selection of RCU implementation
directly off of the SMP and PREEMPT configuration parameters.

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

diff --git a/init/Kconfig b/init/Kconfig
index 2de5b1c..79ac52b 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -340,6 +340,7 @@ choice
 
 config TREE_RCU
        bool "Tree-based hierarchical RCU"
+       depends on !PREEMPT && SMP
        help
          This option selects the RCU implementation that is
          designed for very large SMP system with hundreds or