mm: return boolean from page_is_file_cache()

page_is_file_cache() has been used for both boolean checks and LRU
arithmetic, which was always a bit weird.

Now that page_lru_base_type() exists for LRU arithmetic, make
page_is_file_cache() a real predicate function and adjust the
boolean-using callsites to drop those pesky double negations.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-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/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 99977ff..8835b87 100644 (file)
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -5,7 +5,7 @@
  * page_is_file_cache - should the page be on a file LRU or anon LRU?
  * @page: the page to test
  *
- * Returns LRU_FILE if @page is page cache page backed by a regular filesystem,
+ * Returns 1 if @page is page cache page backed by a regular filesystem,
  * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed.
  * Used by functions that manipulate the LRU lists, to sort a page
  * onto the right LRU list.
@@ -16,11 +16,7 @@
  */
 static inline int page_is_file_cache(struct page *page)
 {
-       if (PageSwapBacked(page))
-               return 0;
-
-       /* The page is page cache backed by a normal filesystem. */
-       return LRU_FILE;
+       return !PageSwapBacked(page);
 }
 
 static inline void

diff --git a/mm/migrate.c b/mm/migrate.c
index b535a2c..e97e513 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -68,7 +68,7 @@ int putback_lru_pages(struct list_head *l)
        list_for_each_entry_safe(page, page2, l, lru) {
                list_del(&page->lru);
                dec_zone_page_state(page, NR_ISOLATED_ANON +
-                                   !!page_is_file_cache(page));
+                               page_is_file_cache(page));
                putback_lru_page(page);
                count++;
        }
@@ -701,7 +701,7 @@ unlock:
                 */
                list_del(&page->lru);
                dec_zone_page_state(page, NR_ISOLATED_ANON +
-                                   !!page_is_file_cache(page));
+                               page_is_file_cache(page));
                putback_lru_page(page);
        }
 
@@ -751,7 +751,7 @@ int migrate_pages(struct list_head *from,
        local_irq_save(flags);
        list_for_each_entry(page, from, lru)
                __inc_zone_page_state(page, NR_ISOLATED_ANON +
-                                     !!page_is_file_cache(page));
+                               page_is_file_cache(page));
        local_irq_restore(flags);
 
        if (!swapwrite)

diff --git a/mm/swap.c b/mm/swap.c
index 168d53e..4a8a59e 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -189,7 +189,7 @@ void activate_page(struct page *page)
                add_page_to_lru_list(zone, page, lru);
                __count_vm_event(PGACTIVATE);
 
-               update_page_reclaim_stat(zone, page, !!file, 1);
+               update_page_reclaim_stat(zone, page, file, 1);
        }
        spin_unlock_irq(&zone->lru_lock);
 }

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 30e56ee..172119c 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -821,7 +821,7 @@ int __isolate_lru_page(struct page *page, int mode, int file)
        if (mode != ISOLATE_BOTH && (!PageActive(page) != !mode))
                return ret;
 
-       if (mode != ISOLATE_BOTH && (!page_is_file_cache(page) != !file))
+       if (mode != ISOLATE_BOTH && page_is_file_cache(page) != file)
                return ret;
 
        /*