mm: introduce for_each_populated_zone() macro

Impact: cleanup

In almost cases, for_each_zone() is used with populated_zone().  It's
because almost function doesn't need memoryless node information.
Therefore, for_each_populated_zone() can help to make code simplify.

This patch has no functional change.

[akpm@linux-foundation.org: small cleanup]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 1aca6cebbb78916aaeb4764b3ec7e7da3276cf91..26ef24076b76a391e94fb395dfc3c820da545155 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -806,6 +806,14 @@ extern struct zone *next_zone(struct zone *zone);
             zone;                                      \
             zone = next_zone(zone))
 
+#define for_each_populated_zone(zone)                  \
+       for (zone = (first_online_pgdat())->node_zones; \
+            zone;                                      \
+            zone = next_zone(zone))                    \
+               if (!populated_zone(zone))              \
+                       ; /* do nothing */              \
+               else
+
 static inline struct zone *zonelist_zone(struct zoneref *zoneref)
 {
        return zoneref->zone;

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index f5fc2d7680f26dbbb84aa1af4b9afa68ba7edf8b..33e2e4a819f97014a6e70e5f06d52e246ba783b3 100644 (file)
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -321,13 +321,10 @@ static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
 
        INIT_LIST_HEAD(list);
 
-       for_each_zone(zone) {
+       for_each_populated_zone(zone) {
                unsigned long zone_start, zone_end;
                struct mem_extent *ext, *cur, *aux;
 
-               if (!populated_zone(zone))
-                       continue;
-
                zone_start = zone->zone_start_pfn;
                zone_end = zone->zone_start_pfn + zone->spanned_pages;
 
@@ -804,8 +801,8 @@ static unsigned int count_free_highmem_pages(void)
        struct zone *zone;
        unsigned int cnt = 0;
 
-       for_each_zone(zone)
-               if (populated_zone(zone) && is_highmem(zone))
+       for_each_populated_zone(zone)
+               if (is_highmem(zone))
                        cnt += zone_page_state(zone, NR_FREE_PAGES);
 
        return cnt;

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index a92c9145155975b306d52dab08fb095e3af8370e..1ee6636414b23316f75c1414255ea124fc2e44eb 100644 (file)
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -229,17 +229,16 @@ int swsusp_shrink_memory(void)
                size = count_data_pages() + PAGES_FOR_IO + SPARE_PAGES;
                tmp = size;
                size += highmem_size;
-               for_each_zone (zone)
-                       if (populated_zone(zone)) {
-                               tmp += snapshot_additional_pages(zone);
-                               if (is_highmem(zone)) {
-                                       highmem_size -=
+               for_each_populated_zone(zone) {
+                       tmp += snapshot_additional_pages(zone);
+                       if (is_highmem(zone)) {
+                               highmem_size -=
                                        zone_page_state(zone, NR_FREE_PAGES);
-                               } else {
-                                       tmp -= zone_page_state(zone, NR_FREE_PAGES);
-                                       tmp += zone->lowmem_reserve[ZONE_NORMAL];
-                               }
+                       } else {
+                               tmp -= zone_page_state(zone, NR_FREE_PAGES);
+                               tmp += zone->lowmem_reserve[ZONE_NORMAL];
                        }
+               }
 
                if (highmem_size < 0)
                        highmem_size = 0;

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a3803ea8c27d5aaaccb5bd2d1f8141786dc9cc27..cbd532161f68c78031174156d954ec94f2d667c8 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -922,13 +922,10 @@ static void drain_pages(unsigned int cpu)
        unsigned long flags;
        struct zone *zone;
 
-       for_each_zone(zone) {
+       for_each_populated_zone(zone) {
                struct per_cpu_pageset *pset;
                struct per_cpu_pages *pcp;
 
-               if (!populated_zone(zone))
-                       continue;
-
                pset = zone_pcp(zone, cpu);
 
                pcp = &pset->pcp;
@@ -1879,10 +1876,7 @@ void show_free_areas(void)
        int cpu;
        struct zone *zone;
 
-       for_each_zone(zone) {
-               if (!populated_zone(zone))
-                       continue;
-
+       for_each_populated_zone(zone) {
                show_node(zone);
                printk("%s per-cpu:\n", zone->name);
 
@@ -1922,12 +1916,9 @@ void show_free_areas(void)
                global_page_state(NR_PAGETABLE),
                global_page_state(NR_BOUNCE));
 
-       for_each_zone(zone) {
+       for_each_populated_zone(zone) {
                int i;
 
-               if (!populated_zone(zone))
-                       continue;
-
                show_node(zone);
                printk("%s"
                        " free:%lukB"
@@ -1967,12 +1958,9 @@ void show_free_areas(void)
                printk("\n");
        }
 
-       for_each_zone(zone) {
+       for_each_populated_zone(zone) {
                unsigned long nr[MAX_ORDER], flags, order, total = 0;
 
-               if (!populated_zone(zone))
-                       continue;
-
                show_node(zone);
                printk("%s: ", zone->name);
 
@@ -2784,11 +2772,7 @@ static int __cpuinit process_zones(int cpu)
 
        node_set_state(node, N_CPU);    /* this node has a cpu */
 
-       for_each_zone(zone) {
-
-               if (!populated_zone(zone))
-                       continue;
-
+       for_each_populated_zone(zone) {
                zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
                                         GFP_KERNEL, node);
                if (!zone_pcp(zone, cpu))

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1bca60f0c52792aa1196d87be55a055cba490c0a..301f057fd115b6df67a43290e5892210c99d8269 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2061,11 +2061,9 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio,
        struct zone *zone;
        unsigned long ret = 0;
 
-       for_each_zone(zone) {
+       for_each_populated_zone(zone) {
                enum lru_list l;
 
-               if (!populated_zone(zone))
-                       continue;
                if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
                        continue;
 

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 8cd81ea1ddc138cf60b93c19554a68cc645160df..9826766f127447c5ee94aec4a86566258a3babf0 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -135,11 +135,7 @@ static void refresh_zone_stat_thresholds(void)
        int cpu;
        int threshold;
 
-       for_each_zone(zone) {
-
-               if (!zone->present_pages)
-                       continue;
-
+       for_each_populated_zone(zone) {
                threshold = calculate_threshold(zone);
 
                for_each_online_cpu(cpu)
@@ -301,12 +297,9 @@ void refresh_cpu_vm_stats(int cpu)
        int i;
        int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 
-       for_each_zone(zone) {
+       for_each_populated_zone(zone) {
                struct per_cpu_pageset *p;
 
-               if (!populated_zone(zone))
-                       continue;
-
                p = zone_pcp(zone, cpu);
 
                for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)