+ mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch added to -mm tree

* + mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch added to -mm tree
@ 2016-07-08 20:33 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2016-07-08 20:33 UTC (permalink / raw)
  To: mgorman, hannes, hillf.zj, iamjoonsoo.kim, mhocko, minchan, riel,
	vbabka, mm-commits


The patch titled
     Subject: mm, vmscan: only wakeup kswapd once per node for the requested classzone
has been added to the -mm tree.  Its filename is
     mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch

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------------------------------------------------------
From: Mel Gorman <mgorman@techsingularity.net>
Subject: mm, vmscan: only wakeup kswapd once per node for the requested classzone

kswapd is woken when zones are below the low watermark but the wakeup
decision is not taking the classzone into account.  Now that reclaim is
node-based, it is only required to wake kswapd once per node and only if
all zones are unbalanced for the requested classzone.

Note that one node might be checked multiple times if the zonelist is
ordered by node because there is no cheap way of tracking what nodes have
already been visited.  For zone-ordering, each node should be checked only
once.

Link: http://lkml.kernel.org/r/1467970510-21195-22-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    8 ++++++--
 mm/vmscan.c     |   13 +++++++++++--
 2 files changed, 17 insertions(+), 4 deletions(-)

diff -puN mm/page_alloc.c~mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone mm/page_alloc.c

--- a/mm/page_alloc.c~mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone
+++ a/mm/page_alloc.c
@@ -3367,10 +3367,14 @@ static void wake_all_kswapds(unsigned in
 {
 	struct zoneref *z;
 	struct zone *zone;
+	pg_data_t *last_pgdat = NULL;
 
 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
-						ac->high_zoneidx, ac->nodemask)
-		wakeup_kswapd(zone, order, ac_classzone_idx(ac));
+					ac->high_zoneidx, ac->nodemask) {
+		if (last_pgdat != zone->zone_pgdat)
+			wakeup_kswapd(zone, order, ac_classzone_idx(ac));
+		last_pgdat = zone->zone_pgdat;
+	}
 }
 
 static inline unsigned int
diff -puN mm/vmscan.c~mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone
+++ a/mm/vmscan.c
@@ -3419,6 +3419,7 @@ kswapd_try_sleep:
 void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 {
 	pg_data_t *pgdat;
+	int z;
 
 	if (!populated_zone(zone))
 		return;
@@ -3430,8 +3431,16 @@ void wakeup_kswapd(struct zone *zone, in
 	pgdat->kswapd_order = max(pgdat->kswapd_order, order);
 	if (!waitqueue_active(&pgdat->kswapd_wait))
 		return;
-	if (zone_balanced(zone, order, 0))
-		return;
+
+	/* Only wake kswapd if all zones are unbalanced */
+	for (z = 0; z <= classzone_idx; z++) {
+		zone = pgdat->node_zones + z;
+		if (!populated_zone(zone))
+			continue;
+
+		if (zone_balanced(zone, order, classzone_idx))
+			return;
+	}
 
 	trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order);
 	wake_up_interruptible(&pgdat->kswapd_wait);
_

Patches currently in -mm which might be from mgorman@techsingularity.net are

mm-meminit-always-return-a-valid-node-from-early_pfn_to_nid.patch
mm-meminit-ensure-node-is-online-before-checking-whether-pages-are-uninitialised.patch
mm-meminit-remove-early_page_nid_uninitialised.patch
mm-vmstat-add-infrastructure-for-per-node-vmstats.patch
mm-vmscan-move-lru_lock-to-the-node.patch
mm-vmscan-move-lru-lists-to-node.patch
mm-mmzone-clarify-the-usage-of-zone-padding.patch
mm-vmscan-begin-reclaiming-pages-on-a-per-node-basis.patch
mm-vmscan-have-kswapd-only-scan-based-on-the-highest-requested-zone.patch
mm-vmscan-make-kswapd-reclaim-in-terms-of-nodes.patch
mm-vmscan-remove-balance-gap.patch
mm-vmscan-simplify-the-logic-deciding-whether-kswapd-sleeps.patch
mm-vmscan-by-default-have-direct-reclaim-only-shrink-once-per-node.patch
mm-vmscan-remove-duplicate-logic-clearing-node-congestion-and-dirty-state.patch
mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone.patch
mm-vmscan-make-shrink_node-decisions-more-node-centric.patch
mm-memcg-move-memcg-limit-enforcement-from-zones-to-nodes.patch
mm-workingset-make-working-set-detection-node-aware.patch
mm-page_alloc-consider-dirtyable-memory-in-terms-of-nodes.patch
mm-move-page-mapped-accounting-to-the-node.patch
mm-rename-nr_anon_pages-to-nr_anon_mapped.patch
mm-move-most-file-based-accounting-to-the-node.patch
mm-move-vmscan-writes-and-file-write-accounting-to-the-node.patch
mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch
mm-page_alloc-wake-kswapd-based-on-the-highest-eligible-zone.patch
mm-convert-zone_reclaim-to-node_reclaim.patch
mm-vmscan-avoid-passing-in-classzone_idx-unnecessarily-to-shrink_node.patch
mm-vmscan-avoid-passing-in-classzone_idx-unnecessarily-to-compaction_ready.patch
mm-vmscan-avoid-passing-in-remaining-unnecessarily-to-prepare_kswapd_sleep.patch
mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit.patch
mm-vmscan-add-classzone-information-to-tracepoints.patch
mm-page_alloc-remove-fair-zone-allocation-policy.patch
mm-page_alloc-cache-the-last-node-whose-dirty-limit-is-reached.patch
mm-vmstat-replace-__count_zone_vm_events-with-a-zone-id-equivalent.patch
mm-vmstat-account-per-zone-stalls-and-pages-skipped-during-reclaim.patch
mm-vmstat-print-node-based-stats-in-zoneinfo-file.patch
mm-vmstat-remove-zone-and-node-double-accounting-by-approximating-retries.patch


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