Group short-lived and reclaimable kernel allocations

This patch marks a number of allocations that are either short-lived such as
network buffers or are reclaimable such as inode allocations.  When something
like updatedb is called, long-lived and unmovable kernel allocations tend to
be spread throughout the address space which increases fragmentation.

This patch groups these allocations together as much as possible by adding a
new MIGRATE_TYPE.  The MIGRATE_RECLAIMABLE type is for allocations that can be
reclaimed on demand, but not moved.  i.e.  they can be migrated by deleting
them and re-reading the information from elsewhere.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 7d7e4fe0fda8..4721e9aa3ced 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -35,10 +35,12 @@
 
 #ifdef CONFIG_PAGE_GROUP_BY_MOBILITY
 #define MIGRATE_UNMOVABLE     0
-#define MIGRATE_MOVABLE       1
-#define MIGRATE_TYPES         2
+#define MIGRATE_RECLAIMABLE   1
+#define MIGRATE_MOVABLE       2
+#define MIGRATE_TYPES         3
 #else
 #define MIGRATE_UNMOVABLE     0
+#define MIGRATE_UNRECLAIMABLE 0
 #define MIGRATE_MOVABLE       0
 #define MIGRATE_TYPES         1
 #endif