+ mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix.patch added to -mm tree

+ mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm, vmscan: prevent kswapd sleeping prematurely due to mismatched classzone_idx -fix
has been added to the -mm tree.  Its filename is
     mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix.patch

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------------------------------------------------------
From: Mel Gorman <mgorman@suse.de>
Subject: mm, vmscan: prevent kswapd sleeping prematurely due to mismatched classzone_idx -fix

The patch "mm, vmscan: prevent kswapd sleeping prematurely due to mismatched
classzone_idx" has different initial starting conditions when kswapd
is asleep. kswapd initialises it properly when it starts but the patch
initialises kswapd_classzone_idx early and trips on a warning in
free_area_init_node. This patch leaves the kswapd_classzone_idx as zero
and defers to kswapd to initialise it properly when it starts.

This is a fix to the mmotm patch
mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx.patch

Link: http://lkml.kernel.org/r/20170406174538.5msrznj6nt6qpbx5@suse.de
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory_hotplug.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff -puN mm/memory_hotplug.c~mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix
+++ a/mm/memory_hotplug.c
@@ -1208,10 +1208,14 @@ static pg_data_t __ref *hotadd_new_pgdat
 
 		arch_refresh_nodedata(nid, pgdat);
 	} else {
-		/* Reset the nr_zones, order and classzone_idx before reuse */
+		/*
+		 * Reset the nr_zones, order and classzone_idx before reuse.
+		 * Note that kswapd will init kswapd_classzone_idx properly
+		 * when it starts in the near future.
+		 */
 		pgdat->nr_zones = 0;
 		pgdat->kswapd_order = 0;
-		pgdat->kswapd_classzone_idx = MAX_NR_ZONES;
+		pgdat->kswapd_classzone_idx = 0;
 	}
 
 	/* we can use NODE_DATA(nid) from here */
_

Patches currently in -mm which might be from mgorman@suse.de are

mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx-fix.patch