mm: migrate: support non-lru movable page migration

[mirror_ubuntu-zesty-kernel.git] / Documentation / filesystems / vfs.txt

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index c61a223ef3ff9edea7a95b575871a0f441dade40..900360cbcdaed762b597d1d3fe1343c15b907df2 100644 (file)
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -592,9 +592,14 @@ struct address_space_operations {
        int (*releasepage) (struct page *, int);
        void (*freepage)(struct page *);
        ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
+       /* isolate a page for migration */
+       bool (*isolate_page) (struct page *, isolate_mode_t);
        /* migrate the contents of a page to the specified target */
        int (*migratepage) (struct page *, struct page *);
+       /* put migration-failed page back to right list */
+       void (*putback_page) (struct page *);
        int (*launder_page) (struct page *);
+
        int (*is_partially_uptodate) (struct page *, unsigned long,
                                        unsigned long);
        void (*is_dirty_writeback) (struct page *, bool *, bool *);
@@ -747,6 +752,10 @@ struct address_space_operations {
         and transfer data directly between the storage and the
         application's address space.
 
+  isolate_page: Called by the VM when isolating a movable non-lru page.
+       If page is successfully isolated, VM marks the page as PG_isolated
+       via __SetPageIsolated.
+
   migrate_page:  This is used to compact the physical memory usage.
         If the VM wants to relocate a page (maybe off a memory card
         that is signalling imminent failure) it will pass a new page
@@ -754,6 +763,8 @@ struct address_space_operations {
        transfer any private data across and update any references
         that it has to the page.
 
+  putback_page: Called by the VM when isolated page's migration fails.
+
   launder_page: Called before freeing a page - it writes back the dirty page. To
        prevent redirtying the page, it is kept locked during the whole
        operation.