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, 3 insertions, 1 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index d859354b9e51..3a5bad3ad126 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -24,12 +24,14 @@
 #define SLAB_HWCACHE_ALIGN      0x00002000UL    /* Align objs on cache lines */
 #define SLAB_CACHE_DMA          0x00004000UL    /* Use GFP_DMA memory */
 #define SLAB_STORE_USER         0x00010000UL    /* DEBUG: Store the last owner for bug hunting */
-#define SLAB_RECLAIM_ACCOUNT    0x00020000UL    /* Objects are reclaimable */
 #define SLAB_PANIC              0x00040000UL    /* Panic if kmem_cache_create() fails */
 #define SLAB_DESTROY_BY_RCU     0x00080000UL    /* Defer freeing slabs to RCU */
 #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
 #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
 
+/* The following flags affect the page allocator grouping pages by mobility */
+#define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
+#define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
 /*
  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
  *