[RFC PATCH 02/10] mm: Helper routines

[Srivatsa S. Bhat]

From: Ankita Garg <gargankita@xxxxxxxxx>

With the introduction of regions, helper routines are needed to walk through
all the regions and zones inside a node. This patch adds these helper
routines.

Signed-off-by: Ankita Garg <gargankita@xxxxxxxxx>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---

 include/linux/mm.h     |    7 ++-----
 include/linux/mmzone.h |   22 +++++++++++++++++++---
 mm/mmzone.c            |   48 ++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 65 insertions(+), 12 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa06804..70f1009 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -693,11 +693,6 @@ static inline int page_to_nid(const struct page *page)
 }
 #endif
 
-static inline struct zone *page_zone(const struct page *page)
-{
-	return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
-}
-
 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
 static inline void set_page_section(struct page *page, unsigned long section)
 {
@@ -711,6 +706,8 @@ static inline unsigned long page_to_section(const struct page *page)
 }
 #endif
 
+struct zone *page_zone(struct page *page);
+
 static inline void set_page_zone(struct page *page, enum zone_type zone)
 {
 	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 3f9b106..6f5d533 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -800,7 +800,7 @@ unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
 /*
  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
  */
-#define zone_idx(zone)		((zone) - (zone)->zone_pgdat->node_zones)
+#define zone_idx(zone)		((zone) - (zone)->zone_mem_region->region_zones)
 
 static inline int populated_zone(struct zone *zone)
 {
@@ -907,7 +907,9 @@ extern struct pglist_data contig_page_data;
 
 extern struct pglist_data *first_online_pgdat(void);
 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
+extern struct zone *first_zone(void);
 extern struct zone *next_zone(struct zone *zone);
+extern struct mem_region *next_mem_region(struct mem_region *region);
 
 /**
  * for_each_online_pgdat - helper macro to iterate over all online nodes
@@ -917,6 +919,20 @@ extern struct zone *next_zone(struct zone *zone);
 	for (pgdat = first_online_pgdat();		\
 	     pgdat;					\
 	     pgdat = next_online_pgdat(pgdat))
+
+
+/**
+ * for_each_mem_region_in_node - helper macro to iterate over all the memory
+ * regions in a node.
+ * @region - pointer to a struct mem_region variable
+ * @nid - node id of the node
+ */
+#define for_each_mem_region_in_node(region, nid)	\
+	for (region = (NODE_DATA(nid))->node_regions;	\
+	     region;					\
+	     region = next_mem_region(region))
+
+
 /**
  * for_each_zone - helper macro to iterate over all memory zones
  * @zone - pointer to struct zone variable
@@ -925,12 +941,12 @@ extern struct zone *next_zone(struct zone *zone);
  * fills it in.
  */
 #define for_each_zone(zone)			        \
-	for (zone = (first_online_pgdat())->node_zones; \
+	for (zone = (first_zone()); 			\
 	     zone;					\
 	     zone = next_zone(zone))
 
 #define for_each_populated_zone(zone)		        \
-	for (zone = (first_online_pgdat())->node_zones; \
+	for (zone = (first_zone()); 			\
 	     zone;					\
 	     zone = next_zone(zone))			\
 		if (!populated_zone(zone))		\
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 3cef80f..d32d10a 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -23,22 +23,62 @@ struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
 	return NODE_DATA(nid);
 }
 
+struct mem_region *next_mem_region(struct mem_region *region)
+{
+	int next_region = region->region + 1;
+	pg_data_t *pgdat = NODE_DATA(region->node);
+
+	if (next_region == pgdat->nr_node_regions)
+		return NULL;
+	return &(pgdat->node_regions[next_region]);
+}
+
+struct zone *first_zone(void)
+{
+	return (first_online_pgdat())->node_regions[0].region_zones;
+}
+
+struct zone *page_zone(struct page *page)
+{
+        pg_data_t *pgdat  = NODE_DATA(page_to_nid(page));
+        unsigned long pfn = page_to_pfn(page);
+        struct mem_region *region;
+
+        for_each_mem_region_in_node(region, pgdat->node_id) {
+                unsigned long end_pfn = region->start_pfn +
+                                        region->spanned_pages;
+
+                if ((pfn >= region->start_pfn) && (pfn < end_pfn))
+                        return &region->region_zones[page_zonenum(page)];
+        }
+
+        return NULL;
+}
+
+
 /*
  * next_zone - helper magic for for_each_zone()
  */
 struct zone *next_zone(struct zone *zone)
 {
 	pg_data_t *pgdat = zone->zone_pgdat;
+	struct mem_region *region = zone->zone_mem_region;
+
+	if (zone < region->region_zones + MAX_NR_ZONES - 1)
+		return ++zone;
 
-	if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
-		zone++;
-	else {
+	region = next_mem_region(region);
+
+	if (region) {
+		zone = region->region_zones;
+	} else {
 		pgdat = next_online_pgdat(pgdat);
 		if (pgdat)
-			zone = pgdat->node_zones;
+			zone = pgdat->node_regions[0].region_zones;
 		else
 			zone = NULL;
 	}
+
 	return zone;
 }
 

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