v4.19.13 snapshot.
diff --git a/mm/mmzone.c b/mm/mmzone.c
new file mode 100644
index 0000000..4686fdc
--- /dev/null
+++ b/mm/mmzone.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/mm/mmzone.c
+ *
+ * management codes for pgdats, zones and page flags
+ */
+
+
+#include <linux/stddef.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+
+struct pglist_data *first_online_pgdat(void)
+{
+ return NODE_DATA(first_online_node);
+}
+
+struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
+{
+ int nid = next_online_node(pgdat->node_id);
+
+ if (nid == MAX_NUMNODES)
+ return NULL;
+ return NODE_DATA(nid);
+}
+
+/*
+ * next_zone - helper magic for for_each_zone()
+ */
+struct zone *next_zone(struct zone *zone)
+{
+ pg_data_t *pgdat = zone->zone_pgdat;
+
+ if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
+ zone++;
+ else {
+ pgdat = next_online_pgdat(pgdat);
+ if (pgdat)
+ zone = pgdat->node_zones;
+ else
+ zone = NULL;
+ }
+ return zone;
+}
+
+static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
+{
+#ifdef CONFIG_NUMA
+ return node_isset(zonelist_node_idx(zref), *nodes);
+#else
+ return 1;
+#endif /* CONFIG_NUMA */
+}
+
+/* Returns the next zone at or below highest_zoneidx in a zonelist */
+struct zoneref *__next_zones_zonelist(struct zoneref *z,
+ enum zone_type highest_zoneidx,
+ nodemask_t *nodes)
+{
+ /*
+ * Find the next suitable zone to use for the allocation.
+ * Only filter based on nodemask if it's set
+ */
+ if (unlikely(nodes == NULL))
+ while (zonelist_zone_idx(z) > highest_zoneidx)
+ z++;
+ else
+ while (zonelist_zone_idx(z) > highest_zoneidx ||
+ (z->zone && !zref_in_nodemask(z, nodes)))
+ z++;
+
+ return z;
+}
+
+#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
+bool memmap_valid_within(unsigned long pfn,
+ struct page *page, struct zone *zone)
+{
+ if (page_to_pfn(page) != pfn)
+ return false;
+
+ if (page_zone(page) != zone)
+ return false;
+
+ return true;
+}
+#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
+
+void lruvec_init(struct lruvec *lruvec)
+{
+ enum lru_list lru;
+
+ memset(lruvec, 0, sizeof(struct lruvec));
+
+ for_each_lru(lru)
+ INIT_LIST_HEAD(&lruvec->lists[lru]);
+}
+
+#if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
+int page_cpupid_xchg_last(struct page *page, int cpupid)
+{
+ unsigned long old_flags, flags;
+ int last_cpupid;
+
+ do {
+ old_flags = flags = page->flags;
+ last_cpupid = page_cpupid_last(page);
+
+ flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
+ flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
+ } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
+
+ return last_cpupid;
+}
+#endif