rcu: Allow TREE_PREEMPT_RCU on UP systems

The TINY_PREEMPT_RCU is complex, does not provide that much memory savings, and therefore TREE_PREEMPT_RCU should be used instead. The systems where the difference between TINY_PREEMPT_RCU and TREE_PREEMPT_RCU are quite small compared to the memory footprint of CONFIG_PREEMPT. This commit therefore takes a first step towards eliminating TINY_PREEMPT_RCU by allowing TREE_PREEMPT_RCU to be configured on !SMP systems. Signed-off-by: Paul E. McKenney <[email protected]> Reviewed-by: Josh Triplett <[email protected]>
sjhung · Jan 29, 2013 · 9fc52d8 · 9fc52d8
1 parent 6bfc09e
commit 9fc52d8
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/init/Kconfig b/init/Kconfig
@@ -453,14 +453,16 @@ config TREE_RCU
 
 config TREE_PREEMPT_RCU
 	bool "Preemptible tree-based hierarchical RCU"
-	depends on PREEMPT && SMP
+	depends on PREEMPT
 	help
 	  This option selects the RCU implementation that is
 	  designed for very large SMP systems with hundreds or
 	  thousands of CPUs, but for which real-time response
 	  is also required.  It also scales down nicely to
 	  smaller systems.
 
+	  Select this option if you are unsure.
+
 config TINY_RCU
 	bool "UP-only small-memory-footprint RCU"
 	depends on !PREEMPT && !SMP