mm, compaction: simplify __alloc_pages_direct_compact feedback interface

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__alloc_pages_direct_compact communicates potential back off by two
variables:
	- deferred_compaction tells that the compaction returned
	  COMPACT_DEFERRED
	- contended_compaction is set when there is a contention on
	  zone->lock resp. zone->lru_lock locks

__alloc_pages_slowpath then backs of for THP allocation requests to
prevent from long stalls. This is rather messy and it would be much
cleaner to return a single compact result value and hide all the nasty
details into __alloc_pages_direct_compact.

This patch shouldn't introduce any functional changes.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

...

This commit is contained in:

Michal Hocko 2016-05-20 16:56:53 -07:00 • committed by Linus Torvalds

parent 4f9a358c36

commit c5d01d0d18

1 changed files with 31 additions and 36 deletions

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mm/page_alloc.c

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