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-rw-r--r--include/linux/mm_inline.h22
-rw-r--r--include/linux/swap.h3
-rw-r--r--mm/vmscan.c100
3 files changed, 112 insertions, 13 deletions
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 47762ca..49cc68a 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -38,3 +38,25 @@ del_page_from_lru(struct zone *zone, struct page *page)
zone->nr_inactive--;
}
}
+
+/*
+ * Isolate one page from the LRU lists.
+ *
+ * - zone->lru_lock must be held
+ */
+static inline int __isolate_lru_page(struct page *page)
+{
+ if (unlikely(!TestClearPageLRU(page)))
+ return 0;
+
+ if (get_page_testone(page)) {
+ /*
+ * It is being freed elsewhere
+ */
+ __put_page(page);
+ SetPageLRU(page);
+ return -ENOENT;
+ }
+
+ return 1;
+}
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 556617b..a491125 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -175,6 +175,9 @@ extern int try_to_free_pages(struct zone **, gfp_t);
extern int shrink_all_memory(int);
extern int vm_swappiness;
+extern int isolate_lru_page(struct page *p);
+extern int putback_lru_pages(struct list_head *l);
+
#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 428c580..261a56e 100644
--- 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.
*
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