summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorBen Widawsky <ben.widawsky@intel.com>2020-06-10 18:41:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-10 19:14:18 -0700
commit496df3d3ab8a407f83330fb8d7160a5f91898c55 (patch)
tree282b6daef9d09f9a0e1a89aed9f99c568fd6e6eb
parentcc989e78472e29c69b196d6985e718c8834027b7 (diff)
mm: add comments on pglist_data zones
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@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200520205443.2757414-1-ben.widawsky@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/mmzone.h14
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index df1f08486d81..c4c37fd12104 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -660,9 +660,21 @@ 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