Commit 4741526b authored May 19, 2016 by Mel Gorman Committed by Linus Torvalds May 19, 2016

mm, page_alloc: restore the original nodemask if the fast path allocation failed

The page allocator fast path uses either the requested nodemask or
cpuset_current_mems_allowed if cpusets are enabled.  If the allocation
context allows watermarks to be ignored then it can also ignore memory
policies.  However, on entering the allocator slowpath the nodemask may
still be cpuset_current_mems_allowed and the policies are enforced.
This patch resets the nodemask appropriately before entering the
slowpath.

Link: http://lkml.kernel.org/r/20160504143628.GU2858@techsingularity.net


Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4e611801

mm/page_alloc.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -3636,6 +3636,12 @@ retry_cpuset:
		alloc_mask = memalloc_noio_flags(gfp_mask);
		ac.spread_dirty_pages = false;

		/*
		* Restore the original nodemask if it was potentially replaced with
		* &cpuset_current_mems_allowed to optimize the fast-path attempt.
		*/
		if (cpusets_enabled())
		ac.nodemask = nodemask;
		page = __alloc_pages_slowpath(alloc_mask, order, &ac);

		no_zone:

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