fix(capacity): prevent cyclic eviction by checking post-eviction allocation

Signed-off-by: guoqinwill <[email protected]>

Author: guoqinwill

pkg/scheduler/plugins/capacity/capacity.go

@@ -122,9 +122,13 @@ func (cp *capacityPlugin) OnSessionOpen(ssn *framework.Session) {
 			exceptReclaimee := allocated.Clone().Sub(reclaimee.Resreq)
 			// When scalar resource not specified in deserved such as "pods", we should skip it and consider it as infinity,
 			// so the following first condition will be true and the current queue will not be reclaimed.
-			if allocated.LessEqual(attr.deserved, api.Infinity) || !attr.guarantee.LessEqual(exceptReclaimee, api.Zero) {
+			// Skip reclaim in two cases:
+			// 1. Current allocated <= deserved (queue not over-quota yet)
+			// 2. Evicting would cause allocated < deserved in any dimension (prevent cyclic eviction)
+			if allocated.LessEqual(attr.deserved, api.Infinity) || exceptReclaimee.LessPartly(attr.deserved, api.Zero) {
 				continue
 			}
+
 			allocated.Sub(reclaimee.Resreq)
 			victims = append(victims, reclaimee)
 		}