[PATCH 8/8] Revert "vmscan: limit direct reclaim for higher order allocations"

[Andrea Arcangeli]

This reverts commit e0887c19b2daa140f20ca8104bdc5740f39dbb86.

If reclaim runs with an high order allocation, it means compaction
failed. That means something went wrong with compaction so we can't
stop reclaim too. We can't assume it failed and was deferred only
because of the too low watermarks in compaction_suitable, it may have
failed for other reasons.

Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
---
 mm/vmscan.c |   16 ----------------
 1 files changed, 0 insertions(+), 16 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index b1a3cb0..a9d1ba4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2128,22 +2128,6 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
 				continue;
 			if (zone->all_unreclaimable && priority != DEF_PRIORITY)
 				continue;	/* Let kswapd poll it */
-			if (COMPACTION_BUILD) {
-				/*
-				 * If we already have plenty of memory
-				 * free for compaction, don't free any
-				 * more.  Even though compaction is
-				 * invoked for any non-zero order,
-				 * only frequent costly order
-				 * reclamation is disruptive enough to
-				 * become a noticable problem, like
-				 * transparent huge page allocations.
-				 */
-				if (sc->order > PAGE_ALLOC_COSTLY_ORDER &&
-					(compaction_suitable(zone, sc->order) ||
-					 compaction_deferred(zone)))
-					continue;
-			}
 			/*
 			 * This steals pages from memory cgroups over softlimit
 			 * and returns the number of reclaimed pages and
--
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