[folded-merged] mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit-fix.patch removed from -mm tree

[folded-merged] mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit-fix.patch removed from -mm tree

[akpm]

The patch titled
     Subject: mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit -fix
has been removed from the -mm tree.  Its filename was
     mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit-fix.patch

This patch was dropped because it was folded into mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit.patch

------------------------------------------------------
From: Mel Gorman <mgorman@techsingularity.net>
Subject: mm, vmscan: Have kswapd reclaim from all zones if reclaiming and buffer_heads_over_limit -fix

Johannes reported that the comment about buffer_heads_over_limit in
balance_pgdat only made sense in the context of the patch. This patch
clarifies the reasoning and how it applies to 32 and 64 bit systems.

This is a fix to the mmotm patch
mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit.patch

Link: http://lkml.kernel.org/r/1468404004-5085-2-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmscan.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff -puN mm/vmscan.c~mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit-fix mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-have-kswapd-reclaim-from-all-zones-if-reclaiming-and-buffer_heads_over_limit-fix
+++ a/mm/vmscan.c
@@ -3134,12 +3134,13 @@ static int balance_pgdat(pg_data_t *pgda
 
 		/*
 		 * If the number of buffer_heads exceeds the maximum allowed
-		 * then consider reclaiming from all zones. This is not
-		 * specific to highmem which may not exist but it is it is
-		 * expected that buffer_heads are stripped in writeback.
-		 * Reclaim may still not go ahead if all eligible zones
-		 * for the original allocation request are balanced to
-		 * avoid excessive reclaim from kswapd.
+		 * then consider reclaiming from all zones. This has a dual
+		 * purpose -- on 64-bit systems it is expected that
+		 * buffer_heads are stripped during active rotation. On 32-bit
+		 * systems, highmem pages can pin lowmem memory and shrinking
+		 * buffers can relieve lowmem pressure. Reclaim may still not
+		 * go ahead if all eligible zones for the original allocation
+		 * request are balanced to avoid excessive reclaim from kswapd.
 		 */
 		if (buffer_heads_over_limit) {
 			for (i = MAX_NR_ZONES - 1; i >= 0; i--) {
_

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

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-account-per-zone-stalls-and-pages-skipped-during-reclaim-fix.patch
mm-vmstat-print-node-based-stats-in-zoneinfo-file.patch
mm-vmstat-remove-zone-and-node-double-accounting-by-approximating-retries.patch
mm-vmstat-remove-zone-and-node-double-accounting-by-approximating-retries-fix.patch
mm-pagevec-release-reacquire-lru_lock-on-pgdat-change.patch
mm-vmscan-update-all-zone-lru-sizes-before-updating-memcg.patch
mm-vmscan-remove-redundant-check-in-shrink_zones.patch
mm-vmscan-release-reacquire-lru_lock-on-pgdat-change.patch
mm-vmscan-release-reacquire-lru_lock-on-pgdat-change-fix.patch
mm-add-per-zone-lru-list-stat-fix.patch
mm-vmscan-remove-highmem_file_pages.patch
mm-vmscan-remove-highmem_file_pages-fix.patch
mm-remove-reclaim-and-compaction-retry-approximations.patch
mm-consider-whether-to-decivate-based-on-eligible-zones-inactive-ratio.patch
mm-vmscan-account-for-skipped-pages-as-a-partial-scan.patch