+ mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch added to -mm tree

+ mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/page_alloc: adding same penalty is enough to get round-robin order
has been added to the -mm tree.  Its filename is
     mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch

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------------------------------------------------------
From: Wei Yang <richard.weiyang@gmail.com>
Subject: mm/page_alloc: adding same penalty is enough to get round-robin order

To make node order in round-robin in the same distance group, we add a
penalty to the first node we got in each round.

To get a round-robin order in the same distance group, we don't need to
decrease the penalty since:

  * find_next_best_node() always iterates node in the same order
  * distance matters more then penalty in find_next_best_node()
  * in nodes with the same distance, the first one would be picked up

So it is fine to increase same penalty when we get the first node in the
same distance group.

Link: https://lkml.kernel.org/r/20220123013537.20491-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Krupa Ramakrishnan <krupa.ramakrishnan@amd.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/mm/page_alloc.c~mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order
+++ a/mm/page_alloc.c
@@ -6319,13 +6319,12 @@ static void build_thisnode_zonelists(pg_
 static void build_zonelists(pg_data_t *pgdat)
 {
 	static int node_order[MAX_NUMNODES];
-	int node, load, nr_nodes = 0;
+	int node, nr_nodes = 0;
 	nodemask_t used_mask = NODE_MASK_NONE;
 	int local_node, prev_node;
 
 	/* NUMA-aware ordering of nodes */
 	local_node = pgdat->node_id;
-	load = nr_online_nodes;
 	prev_node = local_node;
 
 	memset(node_order, 0, sizeof(node_order));
@@ -6337,11 +6336,10 @@ static void build_zonelists(pg_data_t *p
 		 */
 		if (node_distance(local_node, node) !=
 		    node_distance(local_node, prev_node))
-			node_load[node] += load;
+			node_load[node] += nr_online_nodes;
 
 		node_order[nr_nodes++] = node;
 		prev_node = node;
-		load--;
 	}
 
 	build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
_

Patches currently in -mm which might be from richard.weiyang@gmail.com are

mm-page-mapping-folio-mapping-should-have-the-same-offset.patch
mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch
mm-page_alloc-add-penalty-to-local_node.patch