swap: use an array for the LRU pagevecs

Turn the pagevecs into an array just like the LRUs.  This significantly
cleans up the source code and reduces the size of the kernel by about 13kB
after all the LRU lists have been created further down in the split VM
patch series.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: 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>
diff --git a/mm/swap.c b/mm/swap.c
index 82c2b3a..e304504 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -34,8 +34,7 @@
 /* How many pages do we try to swap or page in/out together? */
 int page_cluster;
 
-static DEFINE_PER_CPU(struct pagevec, lru_add_pvecs);
-static DEFINE_PER_CPU(struct pagevec, lru_add_active_pvecs);
+static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
 static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
 
 /*
@@ -186,28 +185,29 @@
 
 EXPORT_SYMBOL(mark_page_accessed);
 
-/**
- * lru_cache_add: add a page to the page lists
- * @page: the page to add
- */
-void lru_cache_add(struct page *page)
+void __lru_cache_add(struct page *page, enum lru_list lru)
 {
-	struct pagevec *pvec = &get_cpu_var(lru_add_pvecs);
+	struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
 
 	page_cache_get(page);
 	if (!pagevec_add(pvec, page))
-		__pagevec_lru_add(pvec);
+		____pagevec_lru_add(pvec, lru);
 	put_cpu_var(lru_add_pvecs);
 }
 
-void lru_cache_add_active(struct page *page)
+/**
+ * lru_cache_add_lru - add a page to a page list
+ * @page: the page to be added to the LRU.
+ * @lru: the LRU list to which the page is added.
+ */
+void lru_cache_add_lru(struct page *page, enum lru_list lru)
 {
-	struct pagevec *pvec = &get_cpu_var(lru_add_active_pvecs);
+	if (PageActive(page)) {
+		ClearPageActive(page);
+	}
 
-	page_cache_get(page);
-	if (!pagevec_add(pvec, page))
-		__pagevec_lru_add_active(pvec);
-	put_cpu_var(lru_add_active_pvecs);
+	VM_BUG_ON(PageLRU(page) || PageActive(page));
+	__lru_cache_add(page, lru);
 }
 
 /*
@@ -217,15 +217,15 @@
  */
 static void drain_cpu_pagevecs(int cpu)
 {
+	struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu);
 	struct pagevec *pvec;
+	int lru;
 
-	pvec = &per_cpu(lru_add_pvecs, cpu);
-	if (pagevec_count(pvec))
-		__pagevec_lru_add(pvec);
-
-	pvec = &per_cpu(lru_add_active_pvecs, cpu);
-	if (pagevec_count(pvec))
-		__pagevec_lru_add_active(pvec);
+	for_each_lru(lru) {
+		pvec = &pvecs[lru - LRU_BASE];
+		if (pagevec_count(pvec))
+			____pagevec_lru_add(pvec, lru);
+	}
 
 	pvec = &per_cpu(lru_rotate_pvecs, cpu);
 	if (pagevec_count(pvec)) {
@@ -380,7 +380,7 @@
  * Add the passed pages to the LRU, then drop the caller's refcount
  * on them.  Reinitialises the caller's pagevec.
  */
-void __pagevec_lru_add(struct pagevec *pvec)
+void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru)
 {
 	int i;
 	struct zone *zone = NULL;
@@ -397,7 +397,9 @@
 		}
 		VM_BUG_ON(PageLRU(page));
 		SetPageLRU(page);
-		add_page_to_inactive_list(zone, page);
+		if (is_active_lru(lru))
+			SetPageActive(page);
+		add_page_to_lru_list(zone, page, lru);
 	}
 	if (zone)
 		spin_unlock_irq(&zone->lru_lock);
@@ -405,34 +407,7 @@
 	pagevec_reinit(pvec);
 }
 
-EXPORT_SYMBOL(__pagevec_lru_add);
-
-void __pagevec_lru_add_active(struct pagevec *pvec)
-{
-	int i;
-	struct zone *zone = NULL;
-
-	for (i = 0; i < pagevec_count(pvec); i++) {
-		struct page *page = pvec->pages[i];
-		struct zone *pagezone = page_zone(page);
-
-		if (pagezone != zone) {
-			if (zone)
-				spin_unlock_irq(&zone->lru_lock);
-			zone = pagezone;
-			spin_lock_irq(&zone->lru_lock);
-		}
-		VM_BUG_ON(PageLRU(page));
-		SetPageLRU(page);
-		VM_BUG_ON(PageActive(page));
-		SetPageActive(page);
-		add_page_to_active_list(zone, page);
-	}
-	if (zone)
-		spin_unlock_irq(&zone->lru_lock);
-	release_pages(pvec->pages, pvec->nr, pvec->cold);
-	pagevec_reinit(pvec);
-}
+EXPORT_SYMBOL(____pagevec_lru_add);
 
 /*
  * Try to drop buffers from the pages in a pagevec