[RFC 02/11] mm/migrate_device: flags for selecting device private THP pages

[Balbir Singh]

Add flags to mark zone device migration pages.

MIGRATE_VMA_SELECT_COMPOUND will be used to select THP pages during
migrate_vma_setup() and MIGRATE_PFN_COMPOUND will make migrating
device pages as compound pages during device pfn migration.

Signed-off-by: Balbir Singh <balbirs at nvidia.com>
---
 include/linux/migrate.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 61899ec7a9a3..b5e4f51e64c7 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -167,6 +167,7 @@ static inline int migrate_misplaced_folio(struct folio *folio, int node)
 #define MIGRATE_PFN_VALID	(1UL << 0)
 #define MIGRATE_PFN_MIGRATE	(1UL << 1)
 #define MIGRATE_PFN_WRITE	(1UL << 3)
+#define MIGRATE_PFN_COMPOUND	(1UL << 4)
 #define MIGRATE_PFN_SHIFT	6
 
 static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
@@ -185,6 +186,7 @@ enum migrate_vma_direction {
 	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
 	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
 	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
+	MIGRATE_VMA_SELECT_COMPOUND = 1 << 3,
 };
 
 struct migrate_vma {
-- 
2.48.1