[PATCH proxmox 02/15] resource-scheduling: scheduler: abstract post-migration stats logic

[Dominik Rusovac <d.rusovac@proxmox.com>]

DRY and hide repeatedly used closure inside reuasble function.

Signed-off-by: Dominik Rusovac <d.rusovac@proxmox.com>
---
 proxmox-resource-scheduling/src/scheduler.rs | 41 ++++++++------------
 1 file changed, 16 insertions(+), 25 deletions(-)

diff --git a/proxmox-resource-scheduling/src/scheduler.rs b/proxmox-resource-scheduling/src/scheduler.rs
index 9078fa72..a12cd519 100644
--- a/proxmox-resource-scheduling/src/scheduler.rs
+++ b/proxmox-resource-scheduling/src/scheduler.rs
@@ -56,6 +56,19 @@ fn calculate_node_imbalance(nodes: &[NodeUsage], to_load: impl Fn(&NodeUsage) ->
     cv / max_cv
 }
 
+/// Returns the hypothetical [`NodeStats`] of `node` with respect to the migration `candidate`.
+fn node_stats_after_migration(candidate: &MigrationCandidate, node: &NodeUsage) -> NodeStats {
+    let mut new_stats = node.stats;
+
+    if node.name == candidate.migration.source_node {
+        new_stats.remove_running_resource(&candidate.stats);
+    } else if node.name == candidate.migration.target_node {
+        new_stats.add_running_resource(&candidate.stats);
+    }
+
+    new_stats
+}
+
 criteria_struct! {
     /// A given alternative.
     struct PveTopsisAlternative {
@@ -216,15 +229,7 @@ impl Scheduler {
     /// See [`calculate_node_imbalance`] for more information.
     fn node_imbalance_with_migration_candidate(&self, candidate: &MigrationCandidate) -> f64 {
         calculate_node_imbalance(&self.nodes, |node| {
-            let mut new_stats = node.stats;
-
-            if node.name == candidate.migration.source_node {
-                new_stats.remove_running_resource(&candidate.stats);
-            } else if node.name == candidate.migration.target_node {
-                new_stats.add_running_resource(&candidate.stats);
-            }
-
-            new_stats.load()
+            node_stats_after_migration(candidate, node).load()
         })
     }
 
@@ -288,22 +293,8 @@ impl Scheduler {
         let matrix = candidates
             .iter()
             .map(|candidate| {
-                let resource_stats = &candidate.stats;
-                let source_node = &candidate.migration.source_node;
-                let target_node = &candidate.migration.target_node;
-
-                self.topsis_alternative_with(|node| {
-                    let mut new_stats = node.stats;
-
-                    if &node.name == source_node {
-                        new_stats.remove_running_resource(resource_stats);
-                    } else if &node.name == target_node {
-                        new_stats.add_running_resource(resource_stats);
-                    }
-
-                    new_stats
-                })
-                .into()
+                self.topsis_alternative_with(|node| node_stats_after_migration(candidate, node))
+                    .into()
             })
             .collect::<Vec<_>>();
 
-- 
2.47.3