Group high-order atomic allocations

In rare cases, the kernel needs to allocate a high-order block of pages
without sleeping.  For example, this is the case with e1000 cards configured
to use jumbo frames.  Migrating or reclaiming pages in this situation is not
an option.

This patch groups these allocations together as much as possible by adding a
new MIGRATE_TYPE.  The MIGRATE_HIGHATOMIC type are exactly what they sound
like.  Care is taken that pages of other migrate types do not use the same
blocks as high-order atomic allocations.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4721e9aa3ced..a8140a9a65e8 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -37,11 +37,13 @@
 #define MIGRATE_UNMOVABLE     0
 #define MIGRATE_RECLAIMABLE   1
 #define MIGRATE_MOVABLE       2
-#define MIGRATE_TYPES         3
+#define MIGRATE_HIGHATOMIC    3
+#define MIGRATE_TYPES         4
 #else
 #define MIGRATE_UNMOVABLE     0
 #define MIGRATE_UNRECLAIMABLE 0
 #define MIGRATE_MOVABLE       0
+#define MIGRATE_HIGHATOMIC    0
 #define MIGRATE_TYPES         1
 #endif