aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMichal Hocko <mhocko@suse.com>2016-08-25 15:17:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-08-26 17:39:35 -0700
commitb32eaf71db6085f2ba54cf3ddf688bfc858219d0 (patch)
tree37b8cea65bfa8d21ab2283bb62d0d6554a002986
parenta5ff1b34e16c203397542d98c49c5c7783193946 (diff)
downloadlinux-stericsson-b32eaf71db6085f2ba54cf3ddf688bfc858219d0.tar.gz
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>
-rw-r--r--mm/Kconfig9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index 78a23c5c302d..be0ee11fa0d9 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -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