From aed0a0e32de387da831284fda25021de32477195 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Tue, 21 Jan 2014 15:51:12 -0800 Subject: [PATCH] mm, page_alloc: warn for non-blockable __GFP_NOFAIL allocation failure __GFP_NOFAIL may return NULL when coupled with GFP_NOWAIT or GFP_ATOMIC. Luckily, nothing currently does such craziness. So instead of causing such allocations to loop (potentially forever), we maintain the current behavior and also warn about the new users of the deprecated flag. Suggested-by: Andrew Morton Signed-off-by: David Rientjes Cc: Mel Gorman Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 84da0e3..533e214 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2525,8 +2525,15 @@ rebalance: } /* Atomic allocations - we can't balance anything */ - if (!wait) + if (!wait) { + /* + * All existing users of the deprecated __GFP_NOFAIL are + * blockable, so warn of any new users that actually allow this + * type of allocation to fail. + */ + WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL); goto nopage; + } /* Avoid recursion of direct reclaim */ if (current->flags & PF_MEMALLOC) -- 2.7.4