[PATCH] page migration reorg

Centralize the page migration functions in anticipation of additional
tinkering.  Creates a new file mm/migrate.c

1. Extract buffer_migrate_page() from fs/buffer.c

2. Extract central migration code from vmscan.c

3. Extract some components from mempolicy.c

4. Export pageout() and remove_from_swap() from vmscan.c

5. Make it possible to configure NUMA systems without page migration
   and non-NUMA systems with page migration.

I had to so some #ifdeffing in mempolicy.c that may need a cleanup.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/swap_state.c b/mm/swap_state.c
index db8a3d3..d7af296 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -15,6 +15,7 @@
 #include <linux/buffer_head.h>
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
+#include <linux/migrate.h>
 
 #include <asm/pgtable.h>