From: Johannes Weiner <hannes@cmpxchg.org>
Date: Wed, 6 Aug 2014 23:06:10 +0000 (-0700)
Subject: mm: vmscan: remove remains of kswapd-managed zone->all_unreclaimable
X-Git-Tag: v4.9.8~5947^2~147
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8d07429319b2836604061f48f7e3dfe78acc060c;p=platform%2Fkernel%2Flinux-rpi3.git

mm: vmscan: remove remains of kswapd-managed zone->all_unreclaimable

shrink_zones() has a special branch to skip the all_unreclaimable()
check during hibernation, because a frozen kswapd can't mark a zone
unreclaimable.

But ever since commit 6e543d5780e3 ("mm: vmscan: fix
do_try_to_free_pages() livelock"), determining a zone to be
unreclaimable is done by directly looking at its scan history and no
longer relies on kswapd setting the per-zone flag.

Remove this branch and let shrink_zones() check the reclaimability of
the target zones regardless of hibernation state.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: KOSAKI Motohiro <Kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0f16ffe..19b5b80 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2534,14 +2534,6 @@ out:
 	if (sc->nr_reclaimed)
 		return sc->nr_reclaimed;
 
-	/*
-	 * As hibernation is going on, kswapd is freezed so that it can't mark
-	 * the zone into all_unreclaimable. Thus bypassing all_unreclaimable
-	 * check.
-	 */
-	if (oom_killer_disabled)
-		return 0;
-
 	/* Aborted reclaim to try compaction? don't OOM, then */
 	if (aborted_reclaim)
 		return 1;