From c2dfcaf0df0cf879cbfabc0cee67c370b06673c9 Mon Sep 17 00:00:00 2001
From: Jonathan Innis <joinnis@amazon.com>
Date: Thu, 30 Jan 2025 15:41:56 -0800
Subject: [PATCH] Don't create new sets when checking compatability

---
 pkg/scheduling/requirement.go  | 40 ++++++++++++++++++++++++++++++++++
 pkg/scheduling/requirements.go |  3 +--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/pkg/scheduling/requirement.go b/pkg/scheduling/requirement.go
index a491baaab6..81c266206a 100644
--- a/pkg/scheduling/requirement.go
+++ b/pkg/scheduling/requirement.go
@@ -187,6 +187,46 @@ func (r *Requirement) Intersection(requirement *Requirement) *Requirement {
 	return &Requirement{Key: r.Key, values: values, complement: complement, greaterThan: greaterThan, lessThan: lessThan, MinValues: minValues}
 }
 
+// nolint:gocyclo
+// HasIntersection is a more efficient implementation of Intersection
+// It validates whether there is an intersection between the two requirements without actually creating the sets
+// This prevents the garbage collector from having to spend cycles cleaning up all of these created set objects
+func (r *Requirement) HasIntersection(requirement *Requirement) bool {
+	greaterThan := maxIntPtr(r.greaterThan, requirement.greaterThan)
+	lessThan := minIntPtr(r.lessThan, requirement.lessThan)
+	if greaterThan != nil && lessThan != nil && *greaterThan >= *lessThan {
+		return false
+	}
+	// Both requirements have a complement
+	if r.complement && requirement.complement {
+		return true
+	}
+	// Only one requirement has a complement
+	if r.complement && !requirement.complement {
+		for value := range requirement.values {
+			if !r.values.Has(value) && withinIntPtrs(value, greaterThan, lessThan) {
+				return true
+			}
+		}
+		return false
+	}
+	if !r.complement && requirement.complement {
+		for value := range r.values {
+			if !requirement.values.Has(value) && withinIntPtrs(value, greaterThan, lessThan) {
+				return true
+			}
+		}
+		return false
+	}
+	// Both requirements are non-complement requirements
+	for value := range r.values {
+		if requirement.values.Has(value) && withinIntPtrs(value, greaterThan, lessThan) {
+			return true
+		}
+	}
+	return false
+}
+
 func (r *Requirement) Any() string {
 	switch r.Operator() {
 	case corev1.NodeSelectorOpIn:
diff --git a/pkg/scheduling/requirements.go b/pkg/scheduling/requirements.go
index 87c36179c4..4f32f417a7 100644
--- a/pkg/scheduling/requirements.go
+++ b/pkg/scheduling/requirements.go
@@ -284,8 +284,7 @@ func (r Requirements) Intersects(requirements Requirements) (errs error) {
 	for key := range r.intersectKeys(requirements) {
 		existing := r.Get(key)
 		incoming := requirements.Get(key)
-		// There must be some value, except
-		if existing.Intersection(incoming).Len() == 0 {
+		if !existing.HasIntersection(incoming) {
 			// where the incoming requirement has operator { NotIn, DoesNotExist }
 			if operator := incoming.Operator(); operator == corev1.NodeSelectorOpNotIn || operator == corev1.NodeSelectorOpDoesNotExist {
 				// and the existing requirement has operator { NotIn, DoesNotExist }