tree 3984a30a79459defc51d96289f8d28c8b7ce72bf
parent 9303662f1616826c551b6b1e958c9cd785356892
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1346971082 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1348178151 -0700

rcu: Shrink RCU based on number of CPUs

Currently, rcu_init_geometry() only reshapes RCU's combining trees
if the leaf fanout is changed at boot time.  This means that by
default, kernels compiled with (say) NR_CPUS=4096 will keep oversized
data structures, even when running on systems with (say) four CPUs.

This commit therefore checks to see if the maximum number of CPUs on
the actual running system (nr_cpu_ids) differs from NR_CPUS, and if so
reshapes the combining trees accordingly.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>