Don't warn about order-1 allocations with __GFP_NOFAIL

Traditionally, we never failed small orders (even regardless of any
__GFP_NOFAIL flags), and slab will allocate order-1 allocations even for
small allocations that could fit in a single page (in order to avoid
excessive fragmentation).

Maybe we should remove this warning entirely, but before making that
judgement, at least limit it to bigger allocations.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index aecc9cd..5d714f8 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1153,10 +1153,10 @@ again:
                         * properly detect and handle allocation failures.
                         *
                         * We most definitely don't want callers attempting to
                         * properly detect and handle allocation failures.
                         *
                         * We most definitely don't want callers attempting to

-                        * allocate greater than single-page units with
+                        * allocate greater than order-1 page units with

                         * __GFP_NOFAIL.
                         */
                         * __GFP_NOFAIL.
                         */

-                       WARN_ON_ONCE(order > 0);
+                       WARN_ON_ONCE(order > 1);

                }
                spin_lock_irqsave(&zone->lock, flags);
                page = __rmqueue(zone, order, migratetype);
                }
                spin_lock_irqsave(&zone->lock, flags);
                page = __rmqueue(zone, order, migratetype);