mm: pagecache insertion fewer atomics

Setting and clearing the page locked when inserting it into swapcache /
pagecache when it has no other references can use non-atomic page flags
operations because no other CPU may be operating on it at this time.

This saves one atomic operation when inserting a page into pagecache.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 43cda7b4b808..3353c9029cef 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -303,7 +303,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
                  * re-using the just freed swap entry for an existing page.
                  * May fail (-ENOMEM) if radix-tree node allocation failed.
                  */
-                set_page_locked(new_page);
+                __set_page_locked(new_page);
                 SetPageSwapBacked(new_page);
                 err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
                 if (likely(!err)) {
@@ -315,7 +315,7 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
                         return new_page;
                 }
                 ClearPageSwapBacked(new_page);
-                clear_page_locked(new_page);
+                __clear_page_locked(new_page);
                 swap_free(entry);
         } while (err != -ENOMEM);