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, 73 insertions, 97 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 187efd47a446..4ccb8651cf22 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1378,42 +1378,29 @@ static void zlc_mark_zone_full(struct zonelist *zonelist, struct zone **z)
  */
 static struct page *
 get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
-                struct zonelist *zonelist, int alloc_flags)
+                struct zonelist *zonelist, int high_zoneidx, int alloc_flags)
 {
         struct zone **z;
         struct page *page = NULL;
-        int classzone_idx = zone_idx(zonelist->zones[0]);
+        int classzone_idx;
         struct zone *zone, *preferred_zone;
         nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
         int zlc_active = 0;             /* set if using zonelist_cache */
         int did_zlc_setup = 0;          /* just call zlc_setup() one time */
-        enum zone_type highest_zoneidx = -1; /* Gets set for policy zonelists */
+
+        z = first_zones_zonelist(zonelist, high_zoneidx);
+        classzone_idx = zone_idx(*z);
+        preferred_zone = *z;
 
 zonelist_scan:
         /*
          * Scan zonelist, looking for a zone with enough free.
          * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
          */
-        z = zonelist->zones;
-        preferred_zone = *z;
-
-        do {
-                /*
-                 * In NUMA, this could be a policy zonelist which contains
-                 * zones that may not be allowed by the current gfp_mask.
-                 * Check the zone is allowed by the current flags
-                 */
-                if (unlikely(alloc_should_filter_zonelist(zonelist))) {
-                        if (highest_zoneidx == -1)
-                                highest_zoneidx = gfp_zone(gfp_mask);
-                        if (zone_idx(*z) > highest_zoneidx)
-                                continue;
-                }
-
+        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
                 if (NUMA_BUILD && zlc_active &&
                         !zlc_zone_worth_trying(zonelist, z, allowednodes))
                                 continue;
-                zone = *z;
                 if ((alloc_flags & ALLOC_CPUSET) &&
                         !cpuset_zone_allowed_softwall(zone, gfp_mask))
                                 goto try_next_zone;
@@ -1447,7 +1434,7 @@ try_next_zone:
                         zlc_active = 1;
                         did_zlc_setup = 1;
                 }
-        } while (*(++z) != NULL);
+        }
 
         if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
                 /* Disable zlc cache for second zonelist scan */
@@ -1465,6 +1452,7 @@ __alloc_pages(gfp_t gfp_mask, unsigned int order,
                 struct zonelist *zonelist)
 {
         const gfp_t wait = gfp_mask & __GFP_WAIT;
+        enum zone_type high_zoneidx = gfp_zone(gfp_mask);
         struct zone **z;
         struct page *page;
         struct reclaim_state reclaim_state;
@@ -1490,7 +1478,7 @@ restart:
         }
 
         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
-                                zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
+                        zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET);
         if (page)
                 goto got_pg;
 
@@ -1534,7 +1522,8 @@ restart:
          * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
          * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
          */
-        page = get_page_from_freelist(gfp_mask, order, zonelist, alloc_flags);
+        page = get_page_from_freelist(gfp_mask, order, zonelist,
+                                                high_zoneidx, alloc_flags);
         if (page)
                 goto got_pg;
 
@@ -1547,7 +1536,7 @@ rebalance:
 nofail_alloc:
                         /* go through the zonelist yet again, ignoring mins */
                         page = get_page_from_freelist(gfp_mask, order,
-                                zonelist, ALLOC_NO_WATERMARKS);
+                                zonelist, high_zoneidx, ALLOC_NO_WATERMARKS);
                         if (page)
                                 goto got_pg;
                         if (gfp_mask & __GFP_NOFAIL) {
@@ -1582,7 +1571,7 @@ nofail_alloc:
 
         if (likely(did_some_progress)) {
                 page = get_page_from_freelist(gfp_mask, order,
-                                                zonelist, alloc_flags);
+                                        zonelist, high_zoneidx, alloc_flags);
                 if (page)
                         goto got_pg;
         } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
@@ -1598,7 +1587,7 @@ nofail_alloc:
                  * under heavy pressure.
                  */
                 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
-                                zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
+                        zonelist, high_zoneidx, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
                 if (page) {
                         clear_zonelist_oom(zonelist);
                         goto got_pg;
@@ -1713,14 +1702,15 @@ EXPORT_SYMBOL(free_pages);
 
 static unsigned int nr_free_zone_pages(int offset)
 {
+        struct zone **z;
+        struct zone *zone;
+
         /* Just pick one node, since fallback list is circular */
         unsigned int sum = 0;
 
         struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
-        struct zone **zonep = zonelist->zones;
-        struct zone *zone;
 
-        for (zone = *zonep++; zone; zone = *zonep++) {
+        for_each_zone_zonelist(zone, z, zonelist, offset) {
                 unsigned long size = zone->present_pages;
                 unsigned long high = zone->pages_high;
                 if (size > high)
@@ -2078,17 +2068,15 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask)
  */
 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
 {
-        enum zone_type i;
         int j;
         struct zonelist *zonelist;
 
-        for (i = 0; i < MAX_NR_ZONES; i++) {
-                zonelist = pgdat->node_zonelists + i;
-                for (j = 0; zonelist->zones[j] != NULL; j++)
-                        ;
-                j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
-                zonelist->zones[j] = NULL;
-        }
+        zonelist = &pgdat->node_zonelists[0];
+        for (j = 0; zonelist->zones[j] != NULL; j++)
+                ;
+        j = build_zonelists_node(NODE_DATA(node), zonelist, j,
+                                                        MAX_NR_ZONES - 1);
+        zonelist->zones[j] = NULL;
 }
 
 /*
@@ -2096,15 +2084,12 @@ static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
  */
 static void build_thisnode_zonelists(pg_data_t *pgdat)
 {
-        enum zone_type i;
         int j;
         struct zonelist *zonelist;
 
-        for (i = 0; i < MAX_NR_ZONES; i++) {
-                zonelist = pgdat->node_zonelists + MAX_NR_ZONES + i;
-                j = build_zonelists_node(pgdat, zonelist, 0, i);
-                zonelist->zones[j] = NULL;
-        }
+        zonelist = &pgdat->node_zonelists[1];
+        j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
+        zonelist->zones[j] = NULL;
 }
 
 /*
@@ -2117,27 +2102,24 @@ static int node_order[MAX_NUMNODES];
 
 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
 {
-        enum zone_type i;
         int pos, j, node;
         int zone_type;          /* needs to be signed */
         struct zone *z;
         struct zonelist *zonelist;
 
-        for (i = 0; i < MAX_NR_ZONES; i++) {
-                zonelist = pgdat->node_zonelists + i;
-                pos = 0;
-                for (zone_type = i; zone_type >= 0; zone_type--) {
-                        for (j = 0; j < nr_nodes; j++) {
-                                node = node_order[j];
-                                z = &NODE_DATA(node)->node_zones[zone_type];
-                                if (populated_zone(z)) {
-                                        zonelist->zones[pos++] = z;
-                                        check_highest_zone(zone_type);
-                                }
+        zonelist = &pgdat->node_zonelists[0];
+        pos = 0;
+        for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
+                for (j = 0; j < nr_nodes; j++) {
+                        node = node_order[j];
+                        z = &NODE_DATA(node)->node_zones[zone_type];
+                        if (populated_zone(z)) {
+                                zonelist->zones[pos++] = z;
+                                check_highest_zone(zone_type);
                         }
                 }
-                zonelist->zones[pos] = NULL;
         }
+        zonelist->zones[pos] = NULL;
 }
 
 static int default_zonelist_order(void)
@@ -2264,19 +2246,15 @@ static void build_zonelists(pg_data_t *pgdat)
 /* Construct the zonelist performance cache - see further mmzone.h */
 static void build_zonelist_cache(pg_data_t *pgdat)
 {
-        int i;
-
-        for (i = 0; i < MAX_NR_ZONES; i++) {
-                struct zonelist *zonelist;
-                struct zonelist_cache *zlc;
-                struct zone **z;
+        struct zonelist *zonelist;
+        struct zonelist_cache *zlc;
+        struct zone **z;
 
-                zonelist = pgdat->node_zonelists + i;
-                zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
-                bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
-                for (z = zonelist->zones; *z; z++)
-                        zlc->z_to_n[z - zonelist->zones] = zone_to_nid(*z);
-        }
+        zonelist = &pgdat->node_zonelists[0];
+        zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
+        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
+        for (z = zonelist->zones; *z; z++)
+                zlc->z_to_n[z - zonelist->zones] = zone_to_nid(*z);
 }
 
 
@@ -2290,45 +2268,43 @@ static void set_zonelist_order(void)
 static void build_zonelists(pg_data_t *pgdat)
 {
         int node, local_node;
-        enum zone_type i,j;
+        enum zone_type j;
+        struct zonelist *zonelist;
 
         local_node = pgdat->node_id;
-        for (i = 0; i < MAX_NR_ZONES; i++) {
-                struct zonelist *zonelist;
 
-                zonelist = pgdat->node_zonelists + i;
+        zonelist = &pgdat->node_zonelists[0];
+        j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
 
-                j = build_zonelists_node(pgdat, zonelist, 0, i);
-                /*
-                 * Now we build the zonelist so that it contains the zones
-                 * of all the other nodes.
-                 * We don't want to pressure a particular node, so when
-                 * building the zones for node N, we make sure that the
-                 * zones coming right after the local ones are those from
-                 * node N+1 (modulo N)
-                 */
-                for (node = local_node + 1; node < MAX_NUMNODES; node++) {
-                        if (!node_online(node))
-                                continue;
-                        j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
-                }
-                for (node = 0; node < local_node; node++) {
-                        if (!node_online(node))
-                                continue;
-                        j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
-                }
-
-                zonelist->zones[j] = NULL;
+        /*
+         * Now we build the zonelist so that it contains the zones
+         * of all the other nodes.
+         * We don't want to pressure a particular node, so when
+         * building the zones for node N, we make sure that the
+         * zones coming right after the local ones are those from
+         * node N+1 (modulo N)
+         */
+        for (node = local_node + 1; node < MAX_NUMNODES; node++) {
+                if (!node_online(node))
+                        continue;
+                j = build_zonelists_node(NODE_DATA(node), zonelist, j,
+                                                        MAX_NR_ZONES - 1);
         }
+        for (node = 0; node < local_node; node++) {
+                if (!node_online(node))
+                        continue;
+                j = build_zonelists_node(NODE_DATA(node), zonelist, j,
+                                                        MAX_NR_ZONES - 1);
+        }
+
+        zonelist->zones[j] = NULL;
 }
 
 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
 static void build_zonelist_cache(pg_data_t *pgdat)
 {
-        int i;
-
-        for (i = 0; i < MAX_NR_ZONES; i++)
-                pgdat->node_zonelists[i].zlcache_ptr = NULL;
+        pgdat->node_zonelists[0].zlcache_ptr = NULL;
+        pgdat->node_zonelists[1].zlcache_ptr = NULL;
 }
 
 #endif  /* CONFIG_NUMA */