[PATCH] SwapMig: CONFIG_MIGRATION fixes

Move move_to_lru, putback_lru_pages and isolate_lru in section surrounded by
CONFIG_MIGRATION saving some codesize for single processor kernels.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 117add066f00d186ce7435167526ef8877245a23..997d838f0e70f7f028ee9daf75937c78b97a7cfd 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -175,10 +175,9 @@ extern int try_to_free_pages(struct zone **, gfp_t);
 extern int shrink_all_memory(int);
 extern int vm_swappiness;
 
+#ifdef CONFIG_MIGRATION
 extern int isolate_lru_page(struct page *p);
 extern int putback_lru_pages(struct list_head *l);
-
-#ifdef CONFIG_MIGRATION
 extern int migrate_pages(struct list_head *l, struct list_head *t);
 #endif
 

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 58270aea669a8e1202ccdf6cc900b26ccb10ba56..daed4a73b761c0abdff9367e9c23235f2598202f 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -569,6 +569,40 @@ keep:
 }
 
 #ifdef CONFIG_MIGRATION
+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;
+}
+
 /*
  * swapout a single page
  * page is locked upon entry, unlocked on exit
@@ -709,6 +743,48 @@ retry_later:
 
        return nr_failed + retry;
 }
+
+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;
+}
 #endif
 
 /*
@@ -758,48 +834,6 @@ 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
  */
@@ -865,40 +899,6 @@ 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.
  *