mm: access zone->node via zone_to_nid() and zone_set_nid()

zone->node is configured only when CONFIG_NUMA=y, so it is a good idea to
have inline functions to access this field in order to avoid ifdef's in c
files.

Link: http://lkml.kernel.org/r/20180730101757.28058-3-osalvador@techadventures.net
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 6 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 455cc3bfae99..6b2324bc61db 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2909,10 +2909,10 @@ static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
         if (!static_branch_likely(&vm_numa_stat_key))
                 return;
 
-        if (z->node != numa_node_id())
+        if (zone_to_nid(z) != numa_node_id())
                 local_stat = NUMA_OTHER;
 
-        if (z->node == preferred_zone->node)
+        if (zone_to_nid(z) == zone_to_nid(preferred_zone))
                 __inc_numa_state(z, NUMA_HIT);
         else {
                 __inc_numa_state(z, NUMA_MISS);
@@ -5278,7 +5278,7 @@ int local_memory_node(int node)
         z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
                                    gfp_zone(GFP_KERNEL),
                                    NULL);
-        return z->zone->node;
+        return zone_to_nid(z->zone);
 }
 #endif
 
@@ -6299,9 +6299,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
                  * And all highmem pages will be managed by the buddy system.
                  */
                 zone->managed_pages = freesize;
-#ifdef CONFIG_NUMA
-                zone->node = nid;
-#endif
+                zone_set_nid(zone, nid);
                 zone->name = zone_names[j];
                 zone->zone_pgdat = pgdat;
                 spin_lock_init(&zone->lock);