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>,
LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone
Date: Fri, 1 Jul 2016 21:01:19 +0100 [thread overview]
Message-ID: <1467403299-25786-12-git-send-email-mgorman@techsingularity.net> (raw)
In-Reply-To: <1467403299-25786-1-git-send-email-mgorman@techsingularity.net>
kswapd scans from highest to lowest for a zone that requires balancing.
This was necessary when reclaim was per-zone to fairly age pages on lower
zones. Now that we are reclaiming on a per-node basis, any eligible zone
can be used and pages will still be aged fairly. This patch avoids
reclaiming excessively unless buffer_heads are over the limit and it's
necessary to reclaim from a higher zone than requested by the waker of
kswapd to relieve low memory pressure.
[hillf.zj@alibaba-inc.com: Force kswapd reclaim no more than needed]
Link: http://lkml.kernel.org/r/1466518566-30034-12-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
mm/vmscan.c | 56 ++++++++++++++++++++++++--------------------------------
1 file changed, 24 insertions(+), 32 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 911142d25de2..2f898ba2ee2e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3141,31 +3141,36 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
sc.nr_reclaimed = 0;
- /* Scan from the highest requested zone to dma */
- for (i = classzone_idx; i >= 0; i--) {
- zone = pgdat->node_zones + i;
- if (!populated_zone(zone))
- continue;
-
- /*
- * If the number of buffer_heads in the machine
- * exceeds the maximum allowed level and this node
- * has a highmem zone, force kswapd to reclaim from
- * it to relieve lowmem pressure.
- */
- if (buffer_heads_over_limit && is_highmem_idx(i)) {
- classzone_idx = i;
- break;
- }
+ /*
+ * If the number of buffer_heads in the machine exceeds the
+ * maximum allowed level then reclaim from all zones. This is
+ * not specific to highmem as highmem may not exist but it is
+ * it is expected that buffer_heads are stripped in writeback.
+ */
+ if (buffer_heads_over_limit) {
+ for (i = MAX_NR_ZONES - 1; i >= 0; i--) {
+ zone = pgdat->node_zones + i;
+ if (!populated_zone(zone))
+ continue;
- if (!zone_balanced(zone, order, 0)) {
classzone_idx = i;
break;
}
}
- if (i < 0)
- goto out;
+ /*
+ * Only reclaim if there are no eligible zones. Check from
+ * high to low zone to avoid prematurely clearing pgdat
+ * congested state.
+ */
+ for (i = classzone_idx; i >= 0; i--) {
+ zone = pgdat->node_zones + i;
+ if (!populated_zone(zone))
+ continue;
+
+ if (zone_balanced(zone, sc.order, classzone_idx))
+ goto out;
+ }
/*
* Do some background aging of the anon list, to give
@@ -3211,19 +3216,6 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
break;
/*
- * Stop reclaiming if any eligible zone is balanced and clear
- * node writeback or congested.
- */
- for (i = 0; i <= classzone_idx; i++) {
- zone = pgdat->node_zones + i;
- if (!populated_zone(zone))
- continue;
-
- if (zone_balanced(zone, sc.order, classzone_idx))
- goto out;
- }
-
- /*
* Raise priority if scanning rate is too low or there was no
* progress in reclaiming pages
*/
--
2.6.4
--
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next prev parent reply other threads:[~2016-07-01 20:03 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-01 20:01 [PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Mel Gorman
2016-07-01 20:01 ` [PATCH 01/31] mm, vmstat: add infrastructure for per-node vmstats Mel Gorman
2016-07-04 23:50 ` Minchan Kim
2016-07-05 8:14 ` Mel Gorman
2016-07-06 0:15 ` Minchan Kim
2016-07-01 20:01 ` [PATCH 02/31] mm, vmscan: move lru_lock to the node Mel Gorman
2016-07-05 0:03 ` Minchan Kim
2016-07-01 20:01 ` [PATCH 03/31] mm, vmscan: move LRU lists to node Mel Gorman
2016-07-05 1:19 ` Minchan Kim
2016-07-05 10:14 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 04/31] mm, vmscan: begin reclaiming pages on a per-node basis Mel Gorman
2016-07-07 1:12 ` Joonsoo Kim
2016-07-07 9:48 ` Mel Gorman
2016-07-08 2:28 ` Joonsoo Kim
2016-07-08 10:05 ` Mel Gorman
2016-07-14 6:28 ` Joonsoo Kim
2016-07-14 7:48 ` Vlastimil Babka
2016-07-18 4:52 ` Joonsoo Kim
2016-07-18 12:11 ` Mel Gorman
2016-07-18 14:27 ` Mel Gorman
2016-07-19 8:30 ` Joonsoo Kim
2016-07-19 14:25 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 05/31] mm, vmscan: have kswapd only scan based on the highest requested zone Mel Gorman
2016-07-01 20:01 ` [PATCH 06/31] mm, vmscan: make kswapd reclaim in terms of nodes Mel Gorman
2016-07-01 20:01 ` [PATCH 07/31] mm, vmscan: remove balance gap Mel Gorman
2016-07-01 20:01 ` [PATCH 08/31] mm, vmscan: simplify the logic deciding whether kswapd sleeps Mel Gorman
2016-07-05 5:59 ` Minchan Kim
2016-07-05 10:26 ` Mel Gorman
2016-07-06 0:30 ` Minchan Kim
2016-07-06 8:31 ` Mel Gorman
2016-07-07 5:51 ` Minchan Kim
2016-07-07 9:56 ` Mel Gorman
2016-07-07 1:20 ` Joonsoo Kim
2016-07-07 10:17 ` Mel Gorman
2016-07-08 2:44 ` Joonsoo Kim
2016-07-08 10:11 ` Mel Gorman
2016-07-14 5:23 ` Joonsoo Kim
2016-07-14 8:32 ` Vlastimil Babka
2016-07-18 5:07 ` Joonsoo Kim
2016-07-18 6:51 ` Vlastimil Babka
2016-07-18 7:24 ` Joonsoo Kim
2016-07-14 9:05 ` Mel Gorman
2016-07-18 5:03 ` Joonsoo Kim
2016-07-01 20:01 ` [PATCH 09/31] mm, vmscan: by default have direct reclaim only shrink once per node Mel Gorman
2016-07-07 1:43 ` Joonsoo Kim
2016-07-07 10:27 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 10/31] mm, vmscan: remove duplicate logic clearing node congestion and dirty state Mel Gorman
2016-07-01 20:01 ` Mel Gorman [this message]
2016-07-05 6:11 ` [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Minchan Kim
2016-07-05 10:38 ` Mel Gorman
2016-07-06 1:25 ` Minchan Kim
2016-07-06 8:42 ` Mel Gorman
2016-07-07 6:27 ` Minchan Kim
2016-07-07 10:55 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 12/31] mm, vmscan: make shrink_node decisions more node-centric Mel Gorman
2016-07-05 6:24 ` Minchan Kim
2016-07-05 10:40 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 13/31] mm, memcg: move memcg limit enforcement from zones to nodes Mel Gorman
2016-07-01 20:01 ` [PATCH 14/31] mm, workingset: make working set detection node-aware Mel Gorman
2016-07-01 20:01 ` [PATCH 15/31] mm, page_alloc: consider dirtyable memory in terms of nodes Mel Gorman
2016-07-01 20:01 ` [PATCH 16/31] mm: move page mapped accounting to the node Mel Gorman
2016-07-01 20:01 ` [PATCH 17/31] mm: rename NR_ANON_PAGES to NR_ANON_MAPPED Mel Gorman
2016-07-01 20:01 ` [PATCH 18/31] mm: move most file-based accounting to the node Mel Gorman
2016-07-01 20:01 ` [PATCH 19/31] mm: move vmscan writes and file write " Mel Gorman
2016-07-01 20:01 ` [PATCH 20/31] mm, vmscan: only wakeup kswapd once per node for the requested classzone Mel Gorman
2016-07-07 1:24 ` Joonsoo Kim
2016-07-07 10:58 ` Mel Gorman
2016-07-01 20:01 ` [PATCH 21/31] mm, page_alloc: Wake kswapd based on the highest eligible zone Mel Gorman
2016-07-01 20:01 ` [PATCH 22/31] mm: convert zone_reclaim to node_reclaim Mel Gorman
2016-07-01 20:01 ` [PATCH 23/31] mm, vmscan: Avoid passing in classzone_idx unnecessarily to shrink_node Mel Gorman
2016-07-01 20:01 ` [PATCH 24/31] mm, vmscan: Avoid passing in classzone_idx unnecessarily to compaction_ready Mel Gorman
2016-07-01 20:01 ` [PATCH 25/31] mm, vmscan: add classzone information to tracepoints Mel Gorman
2016-07-01 20:01 ` [PATCH 26/31] mm, page_alloc: remove fair zone allocation policy Mel Gorman
2016-07-01 20:01 ` [PATCH 27/31] mm: page_alloc: cache the last node whose dirty limit is reached Mel Gorman
2016-07-01 20:01 ` [PATCH 28/31] mm: vmstat: replace __count_zone_vm_events with a zone id equivalent Mel Gorman
2016-07-01 20:01 ` [PATCH 29/31] mm: vmstat: account per-zone stalls and pages skipped during reclaim Mel Gorman
2016-07-01 20:01 ` [PATCH 30/31] mm, vmstat: print node-based stats in zoneinfo file Mel Gorman
2016-07-01 20:01 ` [PATCH 31/31] mm, vmstat: Remove zone and node double accounting by approximating retries Mel Gorman
2016-07-06 0:02 ` Minchan Kim
2016-07-06 8:58 ` Mel Gorman
2016-07-06 9:33 ` Mel Gorman
2016-07-07 6:47 ` Minchan Kim
2016-07-06 18:12 ` Dave Hansen
2016-07-07 11:26 ` Mel Gorman
2016-07-04 1:37 ` [PATCH 00/31] Move LRU page reclaim from zones to nodes v8 Minchan Kim
2016-07-04 4:34 ` Mel Gorman
2016-07-04 8:04 ` Minchan Kim
2016-07-04 9:55 ` Mel Gorman
2016-07-06 1:51 ` Minchan Kim
-- strict thread matches above, loose matches on Subject: below --
2016-07-01 15:37 Mel Gorman
2016-07-01 15:37 ` [PATCH 11/31] mm: vmscan: do not reclaim from kswapd if there is any eligible zone Mel Gorman
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