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From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>, Linux-MM <linux-mm@kvack.org>
Cc: Rik van Riel <riel@surriel.com>, Vlastimil Babka <vbabka@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 09/27] mm, vmscan: By default have direct reclaim only shrink once per node
Date: Fri, 15 Apr 2016 10:13:15 +0100	[thread overview]
Message-ID: <1460711613-2761-10-git-send-email-mgorman@techsingularity.net> (raw)
In-Reply-To: <1460711613-2761-1-git-send-email-mgorman@techsingularity.net>

Direct reclaim iterates over all zones in the zonelist and shrinking them
but this is in conflict with node-based reclaim. In the default case,
only shrink once per node.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
---
 mm/vmscan.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index ef1cfa835138..f0bb2412fc01 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2545,14 +2545,6 @@ static inline bool compaction_ready(struct zone *zone, int order)
  * try to reclaim pages from zones which will satisfy the caller's allocation
  * request.
  *
- * We reclaim from a zone even if that zone is over high_wmark_pages(zone).
- * Because:
- * a) The caller may be trying to free *extra* pages to satisfy a higher-order
- *    allocation or
- * b) The target zone may be at high_wmark_pages(zone) but the lower zones
- *    must go *over* high_wmark_pages(zone) to satisfy the `incremental min'
- *    zone defense algorithm.
- *
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
  *
@@ -2567,6 +2559,7 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc,
 	unsigned long nr_soft_scanned;
 	gfp_t orig_mask;
 	bool reclaimable = false;
+	pg_data_t *last_pgdat = NULL;
 
 	/*
 	 * If the number of buffer_heads in the machine exceeds the maximum
@@ -2579,11 +2572,17 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc,
 
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
 					classzone_idx, sc->nodemask) {
-		if (!populated_zone(zone)) {
-			sc->reclaim_idx--;
-			classzone_idx--;
+		BUG_ON(!populated_zone(zone));
+
+		/*
+		 * Shrink each node in the zonelist once. If the zonelist is
+		 * ordered by zone (not the default) then a node may be
+		 * shrunk multiple times but in that case the user prefers
+		 * lower zones being preserved
+		 */
+		if (zone->zone_pgdat == last_pgdat)
 			continue;
-		}
+		last_pgdat = zone->zone_pgdat;
 
 		/*
 		 * Take care memory controller reclaiming has small influence
-- 
2.6.4

  parent reply	other threads:[~2016-04-15  9:15 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-15  9:13 [PATCH 00/27] Move LRU page reclaim from zones to nodes v5 Mel Gorman
2016-04-15  9:13 ` [PATCH 01/27] mm, vmstat: Add infrastructure for per-node vmstats Mel Gorman
2016-04-15  9:13 ` [PATCH 02/27] mm, vmscan: Move lru_lock to the node Mel Gorman
2016-04-15  9:13 ` [PATCH 03/27] mm, vmscan: Move LRU lists to node Mel Gorman
2016-04-15  9:13 ` [PATCH 04/27] mm, vmscan: Begin reclaiming pages on a per-node basis Mel Gorman
2016-04-15  9:13 ` [PATCH 05/27] mm, vmscan: Have kswapd only scan based on the highest requested zone Mel Gorman
2016-04-15  9:13 ` [PATCH 06/27] mm, vmscan: Make kswapd reclaim in terms of nodes Mel Gorman
2016-04-28  8:36   ` Vlastimil Babka
2016-04-15  9:13 ` [PATCH 07/27] mm, vmscan: Remove balance gap Mel Gorman
2016-04-15  9:13 ` [PATCH 08/27] mm, vmscan: Simplify the logic deciding whether kswapd sleeps Mel Gorman
2016-04-15  9:13 ` Mel Gorman [this message]
2016-04-15  9:13 ` [PATCH 10/27] mm, vmscan: Clear congestion, dirty and need for compaction on a per-node basis Mel Gorman
2016-04-15  9:13 ` [PATCH 11/27] mm: vmscan: Do not reclaim from kswapd if there is any eligible zone Mel Gorman
2016-04-15  9:13 ` [PATCH 12/27] mm, vmscan: Make shrink_node decisions more node-centric Mel Gorman
2016-04-15  9:13 ` [PATCH 13/27] mm, memcg: Move memcg limit enforcement from zones to nodes Mel Gorman
2016-04-15  9:13 ` [PATCH 14/27] mm, workingset: Make working set detection node-aware Mel Gorman
2016-04-15  9:13 ` [PATCH 15/27] mm, page_alloc: Consider dirtyable memory in terms of nodes Mel Gorman
2016-04-15  9:13 ` [PATCH 16/27] mm: Move page mapped accounting to the node Mel Gorman
2016-04-15  9:13 ` [PATCH 17/27] mm: Rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman
2016-04-15  9:13 ` [PATCH 18/27] mm: Move most file-based accounting to the node Mel Gorman
2016-04-15  9:13 ` [PATCH 19/27] mm: Move vmscan writes and file write " Mel Gorman
2016-04-15  9:13 ` [PATCH 20/27] mm, vmscan: Update classzone_idx if buffer_heads_over_limit Mel Gorman
2016-04-15  9:13 ` [PATCH 21/27] mm, vmscan: Only wakeup kswapd once per node for the requested classzone Mel Gorman
2016-04-15  9:13 ` [PATCH 22/27] mm: Convert zone_reclaim to node_reclaim Mel Gorman
2016-04-15  9:13 ` [PATCH 23/27] mm, vmscan: Add classzone information to tracepoints Mel Gorman
2016-04-15  9:13 ` [PATCH 24/27] mm, page_alloc: Remove fair zone allocation policy Mel Gorman
2016-04-15  9:13 ` [PATCH 25/27] mm: page_alloc: Cache the last node whose dirty limit is reached Mel Gorman
2016-04-15  9:13 ` [PATCH 26/27] mm: vmstat: Replace __count_zone_vm_events with a zone id equivalent Mel Gorman
2016-04-15  9:13 ` [PATCH 27/27] mm: vmstat: Account per-zone stalls and pages skipped during reclaim Mel Gorman
  -- strict thread matches above, loose matches on Subject: below --
2016-06-21 14:15 [PATCH 00/27] Move LRU page reclaim from zones to nodes v7 Mel Gorman
2016-06-21 14:15 ` [PATCH 09/27] mm, vmscan: By default have direct reclaim only shrink once per node Mel Gorman
2016-06-09 18:04 [PATCH 00/27] Move LRU page reclaim from zones to nodes v6 Mel Gorman
2016-06-09 18:04 ` [PATCH 09/27] mm, vmscan: By default have direct reclaim only shrink once per node Mel Gorman
2016-06-16  8:59   ` Vlastimil Babka
2016-04-06 11:19 [RFC PATCH 00/27] Move LRU page reclaim from zones to nodes v3 Mel Gorman
2016-04-06 11:20 ` [PATCH 09/27] mm, vmscan: By default have direct reclaim only shrink once per node Mel Gorman

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