sched: Allow SD_NODES_PER_DOMAIN to be overridden

We want to override the default value of SD_NODES_PER_DOMAIN on ppc64,
so move it into linux/topology.h.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

include/linux/topology.h

@@ -201,6 +201,10 @@ int arch_update_cpu_topology(void);
 	.balance_interval	= 64,					\
 }
 
+#ifndef SD_NODES_PER_DOMAIN
+#define SD_NODES_PER_DOMAIN 16
+#endif
+
 #ifdef CONFIG_SCHED_BOOK
 #ifndef SD_BOOK_INIT
 #error Please define an appropriate SD_BOOK_INIT in include/asm/topology.h!!!

kernel/sched.c

@@ -6947,8 +6947,6 @@ static int __init isolated_cpu_setup(char *str)
 
 __setup("isolcpus=", isolated_cpu_setup);
 
-#define SD_NODES_PER_DOMAIN 16
-
 #ifdef CONFIG_NUMA
 
 /**