rcu: Drive configuration directly from SMP and PREEMPT

This commit eliminates the possibility of running TREE_PREEMPT_RCU
when SMP=n and of running TINY_RCU when PREEMPT=y.  People who really
want these combinations can hand-edit init/Kconfig, but eliminating
them as choices for production systems reduces the amount of testing
required.  It will also allow cutting out a few #ifdefs.

Note that running TREE_RCU and TINY_RCU on single-CPU systems using
SMP-built kernels is still supported.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2011-06-08 16:31:33 -07:00
parent b15a2e7d16
commit 8008e129dc

View File

@ -391,7 +391,7 @@ config TREE_RCU
config TREE_PREEMPT_RCU
bool "Preemptible tree-based hierarchical RCU"
depends on PREEMPT
depends on PREEMPT && SMP
help
This option selects the RCU implementation that is
designed for very large SMP systems with hundreds or
@ -401,7 +401,7 @@ config TREE_PREEMPT_RCU
config TINY_RCU
bool "UP-only small-memory-footprint RCU"
depends on !SMP
depends on !PREEMPT && !SMP
help
This option selects the RCU implementation that is
designed for UP systems from which real-time response
@ -410,7 +410,7 @@ config TINY_RCU
config TINY_PREEMPT_RCU
bool "Preemptible UP-only small-memory-footprint RCU"
depends on !SMP && PREEMPT
depends on PREEMPT && !SMP
help
This option selects the RCU implementation that is designed
for real-time UP systems. This option greatly reduces the