121  * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
123  * cachelines.  There are very few zone structures in the machine, so space
140 	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
431 struct zone {  struct
434 	/* zone watermarks, access with *_wmark_pages(zone) macros */
443 	 * wasting several GB of ram we must reserve some of the lower zone  argument
469 	 * spanned_pages is the total pages spanned by the zone, including  argument
473 	 * present_pages is physical pages existing within the zone, which
494 	 * It is a seqlock because it has to be read outside of zone->lock,
498 	 * The span_seq lock is declared along with zone->lock because it is
499 	 * frequently read in proximity to zone->lock.  It's good to
519 	 * of pageblock. Protected by zone->lock.  argument
537 	/* zone flags, see below */  argument
582 	/* Zone statistics */
604 	ZONE_BOOSTED_WATERMARK,		/* zone recently boosted watermarks.  argument
609 static inline unsigned long zone_managed_pages(struct zone *zone)  in zone_managed_pages()  argument
611 	return (unsigned long)atomic_long_read(&zone->managed_pages);  in zone_managed_pages()
614 static inline unsigned long zone_cma_pages(struct zone *zone)  in zone_cma_pages()  argument
617 	return zone->cma_pages;  in zone_cma_pages()
623 static inline unsigned long zone_end_pfn(const struct zone *zone)  in zone_end_pfn()  argument
625 	return zone->zone_start_pfn + zone->spanned_pages;  in zone_end_pfn()
628 static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)  in zone_spans_pfn()  argument
630 	return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);  in zone_spans_pfn()
633 static inline bool zone_is_initialized(struct zone *zone)  in zone_is_initialized()  argument
635 	return zone->initialized;  in zone_is_initialized()
638 static inline bool zone_is_empty(struct zone *zone)  in zone_is_empty()  argument
640 	return zone->spanned_pages == 0;  in zone_is_empty()
645  * intersection with the given zone
647 static inline bool zone_intersects(struct zone *zone,  in zone_intersects()  argument
650 	if (zone_is_empty(zone))  in zone_intersects()
652 	if (start_pfn >= zone_end_pfn(zone) ||  in zone_intersects()
653 	    start_pfn + nr_pages <= zone->zone_start_pfn)  in zone_intersects()
682  * This struct contains information about a zone in a zonelist. It is stored
686 	struct zone *zone;	/* Pointer to actual zone */  member
687 	int zone_idx;		/* zone_idx(zoneref->zone) */
696  * To speed the reading of the zonelist, the zonerefs contain the zone index
700  * zonelist_zone()	- Return the struct zone * for an entry in _zonerefs
701  * zonelist_zone_idx()	- Return the index of the zone for an entry
727  * per-zone basis.
735 	struct zone node_zones[MAX_NR_ZONES];
762 	 * Nests above zone->lock and zone->span_seqlock
862 void wakeup_kswapd(struct zone *zone, gfp_t gfp_mask, int order,
864 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
867 bool zone_watermark_ok(struct zone *z, unsigned int order,
870 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
881 extern void init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
904  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
906 #define zone_idx(zone)		((zone) - (zone)->zone_pgdat->node_zones)  argument
909  * Returns true if a zone has pages managed by the buddy allocator.
911  * populated_zone(). If the whole zone is reserved then we can easily
914 static inline bool managed_zone(struct zone *zone)  in managed_zone()  argument
916 	return zone_managed_pages(zone);  in managed_zone()
919 /* Returns true if a zone has memory */
920 static inline bool populated_zone(struct zone *zone)  in populated_zone()  argument
922 	return zone->present_pages;  in populated_zone()
926 static inline int zone_to_nid(struct zone *zone)  in zone_to_nid()  argument
928 	return zone->node;  in zone_to_nid()
931 static inline void zone_set_nid(struct zone *zone, int nid)  in zone_set_nid()  argument
933 	zone->node = nid;  in zone_set_nid()
936 static inline int zone_to_nid(struct zone *zone)  in zone_to_nid()  argument
941 static inline void zone_set_nid(struct zone *zone, int nid) {}  in zone_set_nid()  argument
977  * is_highmem - helper function to quickly check if a struct zone is a
978  *              highmem zone or not.  This is an attempt to keep references
980  * @zone - pointer to struct zone variable
982 static inline int is_highmem(struct zone *zone)  in is_highmem()  argument
985 	return is_highmem_idx(zone_idx(zone));  in is_highmem()
991 /* These two functions are used to setup the per zone pages min values */
1027 extern struct zone *next_zone(struct zone *zone);
1040  * @zone - pointer to struct zone variable
1042  * The user only needs to declare the zone variable, for_each_zone
1045 #define for_each_zone(zone)			        \  argument
1046 	for (zone = (first_online_pgdat())->node_zones; \
1047 	     zone;					\
1048 	     zone = next_zone(zone))
1050 #define for_each_populated_zone(zone)		        \  argument
1051 	for (zone = (first_online_pgdat())->node_zones; \
1052 	     zone;					\
1053 	     zone = next_zone(zone))			\
1054 		if (!populated_zone(zone))		\
1058 static inline struct zone *zonelist_zone(struct zoneref *zoneref)  in zonelist_zone()
1060 	return zoneref->zone;  in zonelist_zone()
1070 	return zone_to_nid(zoneref->zone);  in zonelist_node_idx()
1078 …* next_zones_zonelist - Returns the next zone at or below highest_zoneidx within the allowed nodem…
1080  * @highest_zoneidx - The zone index of the highest zone to return
1083  * This function returns the next zone at or below a given zone index that is
1085  * search. The zoneref returned is a cursor that represents the current zone
1099 …* first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nod…
1100  * @zonelist - The zonelist to search for a suitable zone
1101  * @highest_zoneidx - The zone index of the highest zone to return
1103  * @return - Zoneref pointer for the first suitable zone found (see below)
1105  * This function returns the first zone at or below a given zone index that is
1110  * When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
1123 …elper macro to iterate over valid zones in a zonelist at or below a given zone index and within a …
1124  * @zone - The current zone in the iterator
1127  * @highidx - The zone index of the highest zone to return
1130  * This iterator iterates though all zones at or below a given zone index and
1133 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \  argument
1134 	for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z);	\
1135 		zone;							\
1137 			zone = zonelist_zone(z))
1139 #define for_next_zone_zonelist_nodemask(zone, z, highidx, nodemask) \  argument
1140 	for (zone = z->zone;	\
1141 		zone;							\
1143 			zone = zonelist_zone(z))
1147 …ne_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
1148  * @zone - The current zone in the iterator
1151  * @highidx - The zone index of the highest zone to return
1153  * This iterator iterates though all zones at or below a given zone index.
1155 #define for_each_zone_zonelist(zone, z, zlist, highidx) \  argument
1156 	for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
1221 	/* See declaration of similar field in struct zone */