[PATCH] Swap Migration V5: LRU operations

[linux-2.6-omap-h63xx.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 428c5801d4b45cf19be318079ed23c8c55a7ccfd..261a56ee11b690b8e182fbbe84a0b42c097c446f 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -593,20 +593,18 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
                page = lru_to_page(src);
                prefetchw_prev_lru_page(page, src, flags);
 
-               if (!TestClearPageLRU(page))
-                       BUG();
-               list_del(&page->lru);
-               if (get_page_testone(page)) {
-                       /*
-                        * It is being freed elsewhere
-                        */
-                       __put_page(page);
-                       SetPageLRU(page);
-                       list_add(&page->lru, src);
-                       continue;
-               } else {
-                       list_add(&page->lru, dst);
+               switch (__isolate_lru_page(page)) {
+               case 1:
+                       /* Succeeded to isolate page */
+                       list_move(&page->lru, dst);
                        nr_taken++;
+                       break;
+               case -ENOENT:
+                       /* Not possible to isolate */
+                       list_move(&page->lru, src);
+                       break;
+               default:
+                       BUG();
                }
        }
 
@@ -614,6 +612,48 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
        return nr_taken;
 }
 
+static void lru_add_drain_per_cpu(void *dummy)
+{
+       lru_add_drain();
+}
+
+/*
+ * Isolate one page from the LRU lists and put it on the
+ * indicated list. Do necessary cache draining if the
+ * page is not on the LRU lists yet.
+ *
+ * Result:
+ *  0 = page not on LRU list
+ *  1 = page removed from LRU list and added to the specified list.
+ * -ENOENT = page is being freed elsewhere.
+ */
+int isolate_lru_page(struct page *page)
+{
+       int rc = 0;
+       struct zone *zone = page_zone(page);
+
+redo:
+       spin_lock_irq(&zone->lru_lock);
+       rc = __isolate_lru_page(page);
+       if (rc == 1) {
+               if (PageActive(page))
+                       del_page_from_active_list(zone, page);
+               else
+                       del_page_from_inactive_list(zone, page);
+       }
+       spin_unlock_irq(&zone->lru_lock);
+       if (rc == 0) {
+               /*
+                * Maybe this page is still waiting for a cpu to drain it
+                * from one of the lru lists?
+                */
+               rc = schedule_on_each_cpu(lru_add_drain_per_cpu, NULL);
+               if (rc == 0 && PageLRU(page))
+                       goto redo;
+       }
+       return rc;
+}
+
 /*
  * shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed
  */
@@ -679,6 +719,40 @@ done:
        pagevec_release(&pvec);
 }
 
+static inline void move_to_lru(struct page *page)
+{
+       list_del(&page->lru);
+       if (PageActive(page)) {
+               /*
+                * lru_cache_add_active checks that
+                * the PG_active bit is off.
+                */
+               ClearPageActive(page);
+               lru_cache_add_active(page);
+       } else {
+               lru_cache_add(page);
+       }
+       put_page(page);
+}
+
+/*
+ * Add isolated pages on the list back to the LRU
+ *
+ * returns the number of pages put back.
+ */
+int putback_lru_pages(struct list_head *l)
+{
+       struct page *page;
+       struct page *page2;
+       int count = 0;
+
+       list_for_each_entry_safe(page, page2, l, lru) {
+               move_to_lru(page);
+               count++;
+       }
+       return count;
+}
+
 /*
  * This moves pages from the active list to the inactive list.
  *