Re: [PATCH v10 5/8] mm/demotion: Build demotion targets based on explicit memory tiers

[Aneesh Kumar K.V]

I missed folding a list walking fix. Use this diff on top
for testing.

diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index b2da34a1f06c..f3d720b7dc6c 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -300,12 +300,12 @@ static void establish_migration_targets(void)
 		nd = &node_demotion[node];
 
 		memtier = __node_get_memory_tier(node);
-		if (!memtier || list_is_last(&memtier->list, &memory_tiers))
+		if (!memtier || list_is_first(&memtier->list, &memory_tiers))
 			continue;
 		/*
 		 * Get the next memtier to find the  demotion node list.
 		 */
-		memtier = list_next_entry(memtier, list);
+		memtier = list_prev_entry(memtier, list);
 
 		/*
 		 * find_next_best_node, use 'used' nodemask as a skip list.
@@ -342,7 +342,7 @@ static void establish_migration_targets(void)
 	 * Once we detect such a memory tier, we consider that tier
 	 * as top tiper from which promotion is not allowed.
 	 */
-	list_for_each_entry_reverse(memtier, &memory_tiers, list) {
+	list_for_each_entry(memtier, &memory_tiers, list) {
 		nodes_and(used, node_states[N_CPU], memtier->nodelist);
 		if (!nodes_empty(used)) {
 			top_tier_id = memtier->id;
@@ -364,7 +364,7 @@ static void establish_migration_targets(void)
 	 */
 	nodes_and(lower_tier, node_states[N_MEMORY], lower_tier);
 
-	list_for_each_entry(memtier, &memory_tiers, list) {
+	list_for_each_entry_reverse(memtier, &memory_tiers, list) {
 		/*
 		 * Keep removing current tier from lower_tier nodes,
 		 * This will remove all nodes in current and above