mm: migrate: Add a tracepoint for migrate_pages

The pgmigrate_success and pgmigrate_fail vmstat counters tells the user
about migration activity but not the type or the reason. This patch adds
a tracepoint to identify the type of page migration and why the page is
being migrated.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index ce7e6671968b..9d1c159e2427 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -7,6 +7,15 @@
 
 typedef struct page *new_page_t(struct page *, unsigned long private, int **);
 
+enum migrate_reason {
+        MR_COMPACTION,
+        MR_MEMORY_FAILURE,
+        MR_MEMORY_HOTPLUG,
+        MR_SYSCALL,             /* also applies to cpusets */
+        MR_MEMPOLICY_MBIND,
+        MR_CMA
+};
+
 #ifdef CONFIG_MIGRATION
 
 extern void putback_lru_pages(struct list_head *l);
@@ -14,7 +23,7 @@ extern int migrate_page(struct address_space *,
                         struct page *, struct page *, enum migrate_mode);
 extern int migrate_pages(struct list_head *l, new_page_t x,
                         unsigned long private, bool offlining,
-                        enum migrate_mode mode);
+                        enum migrate_mode mode, int reason);
 extern int migrate_huge_page(struct page *, new_page_t x,
                         unsigned long private, bool offlining,
                         enum migrate_mode mode);
@@ -35,7 +44,7 @@ extern int migrate_huge_page_move_mapping(struct address_space *mapping,
 static inline void putback_lru_pages(struct list_head *l) {}
 static inline int migrate_pages(struct list_head *l, new_page_t x,
                 unsigned long private, bool offlining,
-                enum migrate_mode mode) { return -ENOSYS; }
+                enum migrate_mode mode, int reason) { return -ENOSYS; }
 static inline int migrate_huge_page(struct page *page, new_page_t x,
                 unsigned long private, bool offlining,
                 enum migrate_mode mode) { return -ENOSYS; }