Commit aed0a0e3 authored Jan 21, 2014 by David Rientjes Committed by Linus Torvalds Jan 21, 2014

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 <akpm@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 55b7c4c9

mm/page_alloc.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -2525,8 +2525,15 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
		}

		/* 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)