Revert "mm, oom: prevent premature OOM killer invocation for high order request"

Revert "mm, oom: prevent premature OOM killer invocation for high order request"

Patch series "reintroduce compaction feedback for OOM decisions".

After several people reported OOM's for order-2 allocations in 4.7 due to
Michal Hocko's OOM rework, he reverted the part that considered compaction
feedback [1] in the decisions to retry reclaim/compaction.  This was to
provide a fix quickly for 4.8 rc and 4.7 stable series, while mmotm had an
almost complete solution that instead improved compaction reliability.

This series completes the mmotm solution and reintroduces the compaction
feedback into OOM decisions.  The first two patches restore the state of
mmotm before the temporary solution was merged, the last patch should be
the missing piece for reliability.  The third patch restricts the hardened
compaction to non-costly orders, since costly orders don't result in OOMs
in the first place.

[1] http://marc.info/?i=20160822093249.GA14916%40dhcp22.suse.cz%3E

This patch (of 4):

Commit 6b4e3181d7bd ("mm, oom: prevent premature OOM killer invocation for
high order request") was intended as a quick fix of OOM regressions for
4.8 and stable 4.7.x kernels.  For a better long-term solution, we still
want to consider compaction feedback, which should be possible after some
more improvements in the following patches.

This reverts commit 6b4e3181d7bd5ca5ab6f45929e4a5ffa7ab4ab7f.

Link: http://lkml.kernel.org/r/20160906135258.18335-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>