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

From: Pavel Tatashin
Date: Wed Jul 25 2018 - 18:01:41 EST


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.

OpenGrok was used to find places where zone->node is accessed. A public one
is available here: http://src.illumos.org/source/

Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
---
include/linux/mm.h | 9 ---------
include/linux/mmzone.h | 26 ++++++++++++++++++++------
mm/mempolicy.c | 4 ++--
mm/mm_init.c | 9 ++-------
mm/page_alloc.c | 10 ++++------
5 files changed, 28 insertions(+), 30 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index fc14a4bec36d..446fc3e6a85b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -942,15 +942,6 @@ static inline int page_zone_id(struct page *page)
return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
}

-static inline int zone_to_nid(struct zone *zone)
-{
-#ifdef CONFIG_NUMA
- return zone->node;
-#else
- return 0;
-#endif
-}
-
#ifdef NODE_NOT_IN_PAGE_FLAGS
extern int page_to_nid(const struct page *page);
#else
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 83b1d11e90eb..805b990b27ab 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -841,6 +841,25 @@ static inline bool populated_zone(struct zone *zone)
return zone->present_pages;
}

+#ifdef CONFIG_NUMA
+static inline int zone_to_nid(struct zone *zone)
+{
+ return zone->node;
+}
+
+static inline void zone_set_nid(struct zone *zone, int nid)
+{
+ zone->node = nid;
+}
+#else
+static inline int zone_to_nid(struct zone *zone)
+{
+ return 0;
+}
+
+static inline void zone_set_nid(struct zone *zone, int nid) {}
+#endif
+
extern int movable_zone;

#ifdef CONFIG_HIGHMEM
@@ -956,12 +975,7 @@ static inline int zonelist_zone_idx(struct zoneref *zoneref)

static inline int zonelist_node_idx(struct zoneref *zoneref)
{
-#ifdef CONFIG_NUMA
- /* zone_to_nid not available in this context */
- return zoneref->zone->node;
-#else
- return 0;
-#endif /* CONFIG_NUMA */
+ return zone_to_nid(zoneref->zone);
}

struct zoneref *__next_zones_zonelist(struct zoneref *z,
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index f0fcf70bcec7..8c1c09b3852a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1784,7 +1784,7 @@ unsigned int mempolicy_slab_node(void)
zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
z = first_zones_zonelist(zonelist, highest_zoneidx,
&policy->v.nodes);
- return z->zone ? z->zone->node : node;
+ return z->zone ? zone_to_nid(z->zone) : node;
}

default:
@@ -2326,7 +2326,7 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
node_zonelist(numa_node_id(), GFP_HIGHUSER),
gfp_zone(GFP_HIGHUSER),
&pol->v.nodes);
- polnid = z->zone->node;
+ polnid = zone_to_nid(z->zone);
break;

default:
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 5b72266b4b03..6838a530789b 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -53,13 +53,8 @@ void __init mminit_verify_zonelist(void)
zone->name);

/* Iterate the zonelist */
- for_each_zone_zonelist(zone, z, zonelist, zoneid) {
-#ifdef CONFIG_NUMA
- pr_cont("%d:%s ", zone->node, zone->name);
-#else
- pr_cont("0:%s ", zone->name);
-#endif /* CONFIG_NUMA */
- }
+ for_each_zone_zonelist(zone, z, zonelist, zoneid)
+ pr_cont("%d:%s ", zone_to_nid(zone), zone->name);
pr_cont("\n");
}
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2dec8056a091..1e6c377ef7d9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2908,10 +2908,10 @@ 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);
@@ -5277,7 +5277,7 @@ 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

@@ -6277,9 +6277,7 @@ 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);
--
2.18.0