[PATCH] page migration: fail if page is in a vma flagged VM_LOCKED

page migration currently simply retries a couple of times if try_to_unmap()
fails without inspecting the return code.

However, SWAP_FAIL indicates that the page is in a vma that has the
VM_LOCKED flag set (if ignore_refs ==1).  We can check for that return code
and avoid retrying the migration.

migrate_page_remove_references() now needs to return a reason why the
failure occured.  So switch migrate_page_remove_references to use -Exx
style error messages.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 62cfd17dc5fe..a9b399402007 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3060,6 +3060,7 @@ int buffer_migrate_page(struct page *newpage, struct page *page)
 {
         struct address_space *mapping = page->mapping;
         struct buffer_head *bh, *head;
+        int rc;
 
         if (!mapping)
                 return -EAGAIN;
@@ -3069,8 +3070,9 @@ int buffer_migrate_page(struct page *newpage, struct page *page)
 
         head = page_buffers(page);
 
-        if (migrate_page_remove_references(newpage, page, 3))
-                return -EAGAIN;
+        rc = migrate_page_remove_references(newpage, page, 3);
+        if (rc)
+                return rc;
 
         bh = head;
         do {