No I meant this:

--- a/mm/internal.h
+++ b/mm/internal.h

@@ -225,7 +225,13 @@ struct compact_control {
        unsigned int nr_freepages;      /* Number of isolated free pages */
        unsigned int nr_migratepages;   /* Number of pages to migrate */
        unsigned long free_pfn;         /* isolate_freepages search base */
-       unsigned long migrate_pfn;      /* isolate_migratepages search base */
+       /*
+        * Acts as an in/out parameter to page isolation for migration.
+        * isolate_migratepages uses it as a search base.
+        * isolate_migratepages_block will update the value to the next pfn
+        * after the last isolated one.
+        */
+       unsigned long migrate_pfn;
        unsigned long fast_start_pfn;   /* a pfn to start linear scan from */
        struct zone *zone;
        unsigned long total_migrate_scanned;