This patch introduces a new Vmemmap page-type so we can better
picture and handle those kind of pages.
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
include/linux/mm.h | 6 ++++++
include/linux/mm_types.h | 5 +++++
include/linux/page-flags.h | 6 ++++++
3 files changed, 17 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ef360fe70aaf..48845f054136 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3126,6 +3126,12 @@ static inline bool debug_guardpage_enabled(void) { return false; }
static inline bool page_is_guard(struct page *page) { return false; }
#endif /* CONFIG_DEBUG_PAGEALLOC */
+static __always_inline unsigned long vmemmap_nr_pages(struct page *page)
+{
+ struct page *head = (struct page *)page->vmemmap_head;
+ return head->vmemmap_pages - (page - head);
+}
+
#if MAX_NUMNODES > 1
void __init setup_nr_node_ids(void);
#else
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index ae891c0c55fc..0bb8de4262c3 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -171,6 +171,11 @@ struct page {
* pmem backed DAX files are mapped.
*/
};
+ struct { /* Vmemmap pages */
+ unsigned long vmemmap_head;
+ unsigned long vmemmap_sections; /* Number of sections */
+ unsigned long vmemmap_pages; /* Number of pages */
+ };
/** @rcu_head: You can use this to free a page by RCU. */
struct rcu_head rcu_head;
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 4f6ba9379112..2bad207515fa 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -718,6 +718,7 @@ PAGEFLAG_FALSE(DoubleMap)
#define PG_kmemcg 0x00000200
#define PG_table 0x00000400
#define PG_guard 0x00000800
+#define PG_vmemmap 0x00001000
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
@@ -784,6 +785,11 @@ PAGE_TYPE_OPS(Table, table)
*/
PAGE_TYPE_OPS(Guard, guard)
+/*
+ * Vmemmap pages (see include/linux/memory_hotplug.h).
+ */
+PAGE_TYPE_OPS(Vmemmap, vmemmap)
+
extern bool is_free_buddy_page(struct page *page);
__PAGEFLAG(Isolated, isolated, PF_ANY);
--
2.26.2
