The patch titled
Subject: mm: vmscan: do not reclaim from kswapd if there is any eligible zone
has been added to the -mm tree. Its filename is
mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm: vmscan: do not reclaim from kswapd if there is any eligible zone
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.
Link: http://lkml.kernel.org/r/1466518566-30034-12-git-send-email-mgorman@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff -puN mm/vmscan.c~mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-do-not-reclaim-from-kswapd-if-there-is-any-eligible-zone
+++ a/mm/vmscan.c
@@ -3138,24 +3138,30 @@ static int balance_pgdat(pg_data_t *pgda
sc.nr_reclaimed = 0;
- /* Scan from the highest requested zone to dma */
+ /*
+ * 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) {
+ for (i = MAX_NR_ZONES - 1; i >= 0; i--) {
+ zone = pgdat->node_zones + i;
+ if (!populated_zone(zone))
+ continue;
+
+ if (is_highmem_idx(i))
+ classzone_idx = i;
+ break;
+ }
+ }
+
+ /* Only reclaim if there are no eligible zones */
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 (!zone_balanced(zone, order, 0)) {
+ if (!zone_balanced(zone, sc.order, classzone_idx)) {
classzone_idx = i;
break;
}
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-slaub-add-__gfp_atomic-to-the-gfp-reclaim-mask.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-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-update-classzone_idx-if-buffer_heads_over_limit.patch
mm-vmscan-only-wakeup-kswapd-once-per-node-for-the-requested-classzone.patch
mm-convert-zone_reclaim-to-node_reclaim.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
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