On Thu 25-02-16 13:36:11, Nikolay Borisov wrote: [...] > > + /* > > + * We most definitely don't want callers attempting to > > + * allocate greater than order-1 page units with __GFP_NOFAIL. > > + */ > > + WARN_ON_ONCE(unlikely(gfp_flags & __GFP_NOFAIL) && (order > 1)); > > WARN_ON_ONCE already includes an unlikely in its definition: > http://lxr.free-electrons.com/source/include/asm-generic/bug.h#L109
OK, I just wanted to keep the condition untouched but you are right the unlikely can be removed. > Reviewed-by: Nikolay Borisov <[email protected]> Thanks! --- >From 6ddc73c6d659224e996d1060974f5a14a1c5bf7d Mon Sep 17 00:00:00 2001 From: Michal Hocko <[email protected]> Date: Thu, 25 Feb 2016 11:29:12 +0100 Subject: [PATCH] mm: remove __GFP_NOFAIL is deprecated comment 647757197cd3 ("mm: clarify __GFP_NOFAIL deprecation status") was incomplete and didn't remove the comment about __GFP_NOFAIL being deprecated in buffered_rmqueue. Let's get rid of this leftover but keep the WARN_ON_ONCE for order > 1 because we should really discourage from using __GFP_NOFAIL with higher order allocations because those are just too subtle. Signed-off-by: Michal Hocko <[email protected]> Reviewed-by: Nikolay Borisov <[email protected]> --- mm/page_alloc.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1993894b4219..b5b7a7b0cad0 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2347,19 +2347,11 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, list_del(&page->lru); pcp->count--; } else { - if (unlikely(gfp_flags & __GFP_NOFAIL)) { - /* - * __GFP_NOFAIL is not to be used in new code. - * - * All __GFP_NOFAIL callers should be fixed so that they - * properly detect and handle allocation failures. - * - * We most definitely don't want callers attempting to - * allocate greater than order-1 page units with - * __GFP_NOFAIL. - */ - WARN_ON_ONCE(order > 1); - } + /* + * We most definitely don't want callers attempting to + * allocate greater than order-1 page units with __GFP_NOFAIL. + */ + WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); spin_lock_irqsave(&zone->lock, flags); page = NULL; -- 2.7.0 -- Michal Hocko SUSE Labs
