mm: introduce zone_reclaim struct

Add zone_reclam_stat struct for later enhancement.

A later patch uses this.  This patch doesn't any behavior change (yet).

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 56 insertions, 35 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 35a7b5e19465..09c14e213b63 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -263,6 +263,19 @@ enum zone_type {
 #error ZONES_SHIFT -- too many zones configured adjust calculation
 #endif
 
+struct zone_reclaim_stat {
+        /*
+         * The pageout code in vmscan.c keeps track of how many of the
+         * mem/swap backed and file backed pages are refeferenced.
+         * The higher the rotated/scanned ratio, the more valuable
+         * that cache is.
+         *
+         * The anon LRU stats live in [0], file LRU stats in [1]
+         */
+        unsigned long           recent_rotated[2];
+        unsigned long           recent_scanned[2];
+};
+
 struct zone {
         /* Fields commonly accessed by the page allocator */
         unsigned long           pages_min, pages_low, pages_high;
@@ -315,16 +328,7 @@ struct zone {
                 unsigned long nr_scan;
         } lru[NR_LRU_LISTS];
 
-        /*
-         * The pageout code in vmscan.c keeps track of how many of the
-         * mem/swap backed and file backed pages are refeferenced.
-         * The higher the rotated/scanned ratio, the more valuable
-         * that cache is.
-         *
-         * The anon LRU stats live in [0], file LRU stats in [1]
-         */
-        unsigned long           recent_rotated[2];
-        unsigned long           recent_scanned[2];
+        struct zone_reclaim_stat reclaim_stat;
 
         unsigned long           pages_scanned;     /* since last reclaim */
         unsigned long           flags;             /* zone flags, see below */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7bf22e045318..5675b3073854 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3523,10 +3523,10 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
                         INIT_LIST_HEAD(&zone->lru[l].list);
                         zone->lru[l].nr_scan = 0;
                 }
-                zone->recent_rotated[0] = 0;
-                zone->recent_rotated[1] = 0;
-                zone->recent_scanned[0] = 0;
-                zone->recent_scanned[1] = 0;
+                zone->reclaim_stat.recent_rotated[0] = 0;
+                zone->reclaim_stat.recent_rotated[1] = 0;
+                zone->reclaim_stat.recent_scanned[0] = 0;
+                zone->reclaim_stat.recent_scanned[1] = 0;
                 zap_zone_vm_stats(zone);
                 zone->flags = 0;
                 if (!size)
diff --git a/mm/swap.c b/mm/swap.c
index 8a98a9c90704..26b07e7bc3d3 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -157,6 +157,7 @@ void  rotate_reclaimable_page(struct page *page)
 void activate_page(struct page *page)
 {
         struct zone *zone = page_zone(page);
+        struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat;
 
         spin_lock_irq(&zone->lru_lock);
         if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
@@ -169,8 +170,8 @@ void activate_page(struct page *page)
                 add_page_to_lru_list(zone, page, lru);
                 __count_vm_event(PGACTIVATE);
 
-                zone->recent_rotated[!!file]++;
-                zone->recent_scanned[!!file]++;
+                reclaim_stat->recent_rotated[!!file]++;
+                reclaim_stat->recent_scanned[!!file]++;
         }
         spin_unlock_irq(&zone->lru_lock);
 }
@@ -385,6 +386,8 @@ void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
 {
         int i;
         struct zone *zone = NULL;
+        struct zone_reclaim_stat *reclaim_stat = NULL;
+
         VM_BUG_ON(is_unevictable_lru(lru));
 
         for (i = 0; i < pagevec_count(pvec); i++) {
@@ -396,6 +399,7 @@ void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
                         if (zone)
                                 spin_unlock_irq(&zone->lru_lock);
                         zone = pagezone;
+                        reclaim_stat = &zone->reclaim_stat;
                         spin_lock_irq(&zone->lru_lock);
                 }
                 VM_BUG_ON(PageActive(page));
@@ -403,10 +407,10 @@ void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
                 VM_BUG_ON(PageLRU(page));
                 SetPageLRU(page);
                 file = is_file_lru(lru);
-                zone->recent_scanned[file]++;
+                reclaim_stat->recent_scanned[file]++;
                 if (is_active_lru(lru)) {
                         SetPageActive(page);
-                        zone->recent_rotated[file]++;
+                        reclaim_stat->recent_rotated[file]++;
                 }
                 add_page_to_lru_list(zone, page, lru);
         }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f75d924cb4f4..03ca923c6656 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -130,6 +130,12 @@ static DECLARE_RWSEM(shrinker_rwsem);
 #define scan_global_lru(sc)     (1)
 #endif
 
+static struct zone_reclaim_stat *get_reclaim_stat(struct zone *zone,
+                                                  struct scan_control *sc)
+{
+        return &zone->reclaim_stat;
+}
+
 /*
  * Add a shrinker callback to be called from the vm
  */
@@ -1029,6 +1035,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
         struct pagevec pvec;
         unsigned long nr_scanned = 0;
         unsigned long nr_reclaimed = 0;
+        struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 
         pagevec_init(&pvec, 1);
 
@@ -1072,10 +1079,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
 
                 if (scan_global_lru(sc)) {
                         zone->pages_scanned += nr_scan;
-                        zone->recent_scanned[0] += count[LRU_INACTIVE_ANON];
-                        zone->recent_scanned[0] += count[LRU_ACTIVE_ANON];
-                        zone->recent_scanned[1] += count[LRU_INACTIVE_FILE];
-                        zone->recent_scanned[1] += count[LRU_ACTIVE_FILE];
+                        reclaim_stat->recent_scanned[0] +=
+                                                      count[LRU_INACTIVE_ANON];
+                        reclaim_stat->recent_scanned[0] +=
+                                                      count[LRU_ACTIVE_ANON];
+                        reclaim_stat->recent_scanned[1] +=
+                                                      count[LRU_INACTIVE_FILE];
+                        reclaim_stat->recent_scanned[1] +=
+                                                      count[LRU_ACTIVE_FILE];
                 }
                 spin_unlock_irq(&zone->lru_lock);
 
@@ -1136,7 +1147,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                         add_page_to_lru_list(zone, page, lru);
                         if (PageActive(page) && scan_global_lru(sc)) {
                                 int file = !!page_is_file_cache(page);
-                                zone->recent_rotated[file]++;
+                                reclaim_stat->recent_rotated[file]++;
                         }
                         if (!pagevec_add(&pvec, page)) {
                                 spin_unlock_irq(&zone->lru_lock);
@@ -1196,6 +1207,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
         struct page *page;
         struct pagevec pvec;
         enum lru_list lru;
+        struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 
         lru_add_drain();
         spin_lock_irq(&zone->lru_lock);
@@ -1208,7 +1220,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
          */
         if (scan_global_lru(sc)) {
                 zone->pages_scanned += pgscanned;
-                zone->recent_scanned[!!file] += pgmoved;
+                reclaim_stat->recent_scanned[!!file] += pgmoved;
         }
 
         if (file)
@@ -1251,7 +1263,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
          * pages in get_scan_ratio.
          */
         if (scan_global_lru(sc))
-                zone->recent_rotated[!!file] += pgmoved;
+                reclaim_stat->recent_rotated[!!file] += pgmoved;
 
         while (!list_empty(&l_inactive)) {
                 page = lru_to_page(&l_inactive);
@@ -1344,6 +1356,7 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
         unsigned long anon, file, free;
         unsigned long anon_prio, file_prio;
         unsigned long ap, fp;
+        struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 
         /* If we have no swap space, do not bother scanning anon pages. */
         if (nr_swap_pages <= 0) {
@@ -1376,17 +1389,17 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
          *
          * anon in [0], file in [1]
          */
-        if (unlikely(zone->recent_scanned[0] > anon / 4)) {
+        if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
                 spin_lock_irq(&zone->lru_lock);
-                zone->recent_scanned[0] /= 2;
-                zone->recent_rotated[0] /= 2;
+                reclaim_stat->recent_scanned[0] /= 2;
+                reclaim_stat->recent_rotated[0] /= 2;
                 spin_unlock_irq(&zone->lru_lock);
         }
 
-        if (unlikely(zone->recent_scanned[1] > file / 4)) {
+        if (unlikely(reclaim_stat->recent_scanned[1] > file / 4)) {
                 spin_lock_irq(&zone->lru_lock);
-                zone->recent_scanned[1] /= 2;
-                zone->recent_rotated[1] /= 2;
+                reclaim_stat->recent_scanned[1] /= 2;
+                reclaim_stat->recent_rotated[1] /= 2;
                 spin_unlock_irq(&zone->lru_lock);
         }
 
@@ -1402,11 +1415,11 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
          * proportional to the fraction of recently scanned pages on
          * each list that were recently referenced and in active use.
          */
-        ap = (anon_prio + 1) * (zone->recent_scanned[0] + 1);
-        ap /= zone->recent_rotated[0] + 1;
+        ap = (anon_prio + 1) * (reclaim_stat->recent_scanned[0] + 1);
+        ap /= reclaim_stat->recent_rotated[0] + 1;
 
-        fp = (file_prio + 1) * (zone->recent_scanned[1] + 1);
-        fp /= zone->recent_rotated[1] + 1;
+        fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1);
+        fp /= reclaim_stat->recent_rotated[1] + 1;
 
         /* Normalize to percentages */
         percent[0] = 100 * ap / (ap + fp + 1);