sched/numa: Export info needed for NUMA balancing on complex topologies

Export some information that is necessary to do placement of
tasks on systems with multi-level NUMA topologies.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: chegu_vinod@hp.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1413530994-9732-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Author: Rik van Riel

kernel/sched/core.c

@@ -6129,6 +6129,7 @@ static void claim_allocations(int cpu, struct sched_domain *sd)
 #ifdef CONFIG_NUMA
 static int sched_domains_numa_levels;
 static int *sched_domains_numa_distance;
+int sched_max_numa_distance;
 static struct cpumask ***sched_domains_numa_masks;
 static int sched_domains_curr_level;
 #endif
@@ -6300,7 +6301,7 @@ static void sched_numa_warn(const char *str)
 	printk(KERN_WARNING "\n");
 }
 
-static bool find_numa_distance(int distance)
+bool find_numa_distance(int distance)
 {
 	int i;
 
@@ -6447,6 +6448,7 @@ static void sched_init_numa(void)
 	sched_domain_topology = tl;
 
 	sched_domains_numa_levels = level;
+	sched_max_numa_distance = sched_domains_numa_distance[level - 1];
 }
 
 static void sched_domains_numa_masks_set(int cpu)

kernel/sched/sched.h

@@ -678,6 +678,11 @@ static inline u64 rq_clock_task(struct rq *rq)
 	return rq->clock_task;
 }
 
+#ifdef CONFIG_NUMA
+extern int sched_max_numa_distance;
+extern bool find_numa_distance(int distance);
+#endif
+
 #ifdef CONFIG_NUMA_BALANCING
 extern void sched_setnuma(struct task_struct *p, int node);
 extern int migrate_task_to(struct task_struct *p, int cpu);