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/lib/radix-tree.c b/lib/radix-tree.c
index 519d3f0..6b26f9d 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -98,7 +98,8 @@ radix_tree_node_alloc(struct radix_tree_root *root)
 	struct radix_tree_node *ret;
 	gfp_t gfp_mask = root_gfp_mask(root);
 
-	ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
+	ret = kmem_cache_alloc(radix_tree_node_cachep,
+				set_migrateflags(gfp_mask, __GFP_RECLAIMABLE));
 	if (ret == NULL && !(gfp_mask & __GFP_WAIT)) {
 		struct radix_tree_preload *rtp;
 
@@ -142,7 +143,8 @@ int radix_tree_preload(gfp_t gfp_mask)
 	rtp = &__get_cpu_var(radix_tree_preloads);
 	while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
 		preempt_enable();
-		node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
+		node = kmem_cache_alloc(radix_tree_node_cachep,
+				set_migrateflags(gfp_mask, __GFP_RECLAIMABLE));
 		if (node == NULL)
 			goto out;
 		preempt_disable();