Commit b32eaf71 authored Aug 25, 2016 by Michal Hocko Committed by Linus Torvalds Aug 26, 2016

mm: clarify COMPACTION Kconfig text

The current wording of the COMPACTION Kconfig help text doesn't
emphasise that disabling COMPACTION might cripple the page allocator
which relies on the compaction quite heavily for high order requests and
an unexpected OOM can happen with the lack of compaction.  Make sure we
are vocal about that.

Link: http://lkml.kernel.org/r/20160823091726.GK23577@dhcp22.suse.cz


Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a5ff1b34

mm/Kconfig

+8 −1

Original line number	Diff line number	Diff line
		@@ -262,7 +262,14 @@ config COMPACTION
		select MIGRATION
		depends on MMU
		help
		Allows the compaction of memory for the allocation of huge pages.
		Compaction is the only memory management component to form
		high order (larger physically contiguous) memory blocks
		reliably. The page allocator relies on compaction heavily and
		the lack of the feature can lead to unexpected OOM killer
		invocations for high order memory requests. You shouldn't
		disable this option unless there really is a strong reason for
		it and then we would be really interested to hear about that at
		linux-mm@kvack.org.

		#
		# support for page migration

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