Commit 496df3d3 authored Jun 10, 2020 by Ben Widawsky Committed by Linus Torvalds Jun 10, 2020

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>

parent cc989e78

include/linux/mmzone.h

+13 −1

Original line number	Diff line number	Diff line
		@@ -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