While making other modifications it was easy to confuse the two struct
members node_zones and node_zonelists. For those already familiar with
the code, this might seem to be a silly patch, but it's quite helpful to
disambiguate the similar-sounding fields
While here, add a small comment on why nr_zones isn't simply MAX_NR_ZONES
Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
---
include/linux/mmzone.h | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git include/linux/mmzone.h include/linux/mmzone.h
index 1b9de7d220fb..4f7c95e9bad8 100644
--- include/linux/mmzone.h
+++ include/linux/mmzone.h
@@ -665,9 +665,21 @@ struct deferred_split {
* per-zone basis.
*/
typedef struct pglist_data {
+ /*
+ * node_zones contains just the zones for THIS node. Not all of the
+ * zones may be populated, but it is the full list. It is referenced by
+ * this node's node_zonelists as well as other node's node_zonelists.
+ */
struct zone node_zones[MAX_NR_ZONES];
+
+ /*
+ * node_zonelists contains references to all zones in all nodes.
+ * Generally the first zones will be references to this node's
+ * node_zones.
+ */
struct zonelist node_zonelists[MAX_ZONELISTS];
- int nr_zones;
+
+ int nr_zones; /* number of populated zones in this node */
#ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
struct page *node_mem_map;
#ifdef CONFIG_PAGE_EXTENSION
--
2.26.2
