mm: use two zonelist that are filtered by GFP mask

Currently a node has two sets of zonelists, one for each zone type in the
system and a second set for GFP_THISNODE allocations.  Based on the zones
allowed by a gfp mask, one of these zonelists is selected.  All of these
zonelists consume memory and occupy cache lines.

This patch replaces the multiple zonelists per-node with two zonelists.  The
first contains all populated zones in the system, ordered by distance, for
fallback allocations when the target/preferred node has no free pages.  The
second contains all populated zones in the node suitable for GFP_THISNODE
allocations.

An iterator macro is introduced called for_each_zone_zonelist() that interates
through each zone allowed by the GFP flags in the selected zonelist.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 19ebbfb20689..80d20cc1c0f8 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1285,6 +1285,8 @@ static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
 #ifdef CONFIG_NUMA
         struct zonelist *zonelist;
         struct zone **z;
+        struct zone *zone;
+        enum zone_type high_zoneidx = gfp_zone(flags);
         struct page *page;
 
         /*
@@ -1310,12 +1312,12 @@ static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
                 return NULL;
 
         zonelist = node_zonelist(slab_node(current->mempolicy), flags);
-        for (z = zonelist->zones; *z; z++) {
+        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
                 struct kmem_cache_node *n;
 
-                n = get_node(s, zone_to_nid(*z));
+                n = get_node(s, zone_to_nid(zone));
 
-                if (n && cpuset_zone_allowed_hardwall(*z, flags) &&
+                if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
                                 n->nr_partial > MIN_PARTIAL) {
                         page = get_partial_node(n);
                         if (page)