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Commit 9fc52d83 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent 6bfc09e2

init/Kconfig

+3 −1
Original line number Original line Diff line number Diff line
@@ -453,7 +453,7 @@ config TREE_RCU 




config TREE_PREEMPT_RCU

config TREE_PREEMPT_RCU

	bool "Preemptible tree-based hierarchical RCU"

	bool "Preemptible tree-based hierarchical RCU"

	depends on PREEMPT && SMP

	depends on PREEMPT

	help

	help

	  This option selects the RCU implementation that is

	  This option selects the RCU implementation that is

	  designed for very large SMP systems with hundreds or

	  designed for very large SMP systems with hundreds or
@@ -461,6 +461,8 @@ config TREE_PREEMPT_RCU 
	  is also required.  It also scales down nicely to

	  is also required.  It also scales down nicely to

	  smaller systems.

	  smaller systems.





	  Select this option if you are unsure.



config TINY_RCU

config TINY_RCU

	bool "UP-only small-memory-footprint RCU"

	bool "UP-only small-memory-footprint RCU"

	depends on !PREEMPT && !SMP

	depends on !PREEMPT && !SMP