Convert cpu_sibling_map to be a per cpu variable

Convert cpu_sibling_map from a static array sized by NR_CPUS to a per_cpu
variable.  This saves sizeof(cpumask_t) * NR unused cpus.  Access is mostly
from startup and CPU HOTPLUG functions.

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 2 deletions

diff --git a/include/asm-powerpc/smp.h b/include/asm-powerpc/smp.h
index 19102bfc14ca..505f35bacaa9 100644
--- a/include/asm-powerpc/smp.h
+++ b/include/asm-powerpc/smp.h
@@ -26,6 +26,7 @@
 #ifdef CONFIG_PPC64
 #include <asm/paca.h>
 #endif
+#include <asm/percpu.h>
 
 extern int boot_cpuid;
 
@@ -58,7 +59,7 @@ extern int smp_hw_index[];
                                         (smp_hw_index[(cpu)] = (phys))
 #endif
 
-extern cpumask_t cpu_sibling_map[NR_CPUS];
+DECLARE_PER_CPU(cpumask_t, cpu_sibling_map);
 
 /* Since OpenPIC has only 4 IPIs, we use slightly different message numbers.
  *
@@ -77,6 +78,7 @@ void smp_init_pSeries(void);
 void smp_init_cell(void);
 void smp_init_celleb(void);
 void smp_setup_cpu_maps(void);
+void smp_setup_cpu_sibling_map(void);
 
 extern int __cpu_disable(void);
 extern void __cpu_die(unsigned int cpu);
diff --git a/include/asm-powerpc/topology.h b/include/asm-powerpc/topology.h
index 0ad21a849b5f..ca23b681ad05 100644
--- a/include/asm-powerpc/topology.h
+++ b/include/asm-powerpc/topology.h
@@ -108,7 +108,7 @@ static inline void sysfs_remove_device_from_node(struct sys_device *dev,
 #ifdef CONFIG_PPC64
 #include <asm/smp.h>
 
-#define topology_thread_siblings(cpu)   (cpu_sibling_map[cpu])
+#define topology_thread_siblings(cpu)   (per_cpu(cpu_sibling_map, cpu))
 #endif
 #endif