Merge pull request #112649 from howardjohn/set/optimize-everything-nothing

k8s-publishing-bot · k8s-publishing-bot · commit 9e85d3af4ae2 · 2022-11-03T07:50:33.000Z
Optimize `Everything` and `Nothing` label selectors

Kubernetes-commit: bbe050dd01fbf60661b8b8d8f750a0dc675dcbb9
diff --git a/pkg/labels/selector.go b/pkg/labels/selector.go
@@ -74,9 +74,12 @@ type Selector interface {
 	RequiresExactMatch(label string) (value string, found bool)
 }
 
+// Sharing this saves 1 alloc per use; this is safe because it's immutable.
+var sharedEverythingSelector Selector = internalSelector{}
+
 // Everything returns a selector that matches all labels.
 func Everything() Selector {
-	return internalSelector{}
+	return sharedEverythingSelector
 }
 
 type nothingSelector struct{}
@@ -91,9 +94,12 @@ func (n nothingSelector) RequiresExactMatch(label string) (value string, found b
 	return "", false
 }
 
+// Sharing this saves 1 alloc per use; this is safe because it's immutable.
+var sharedNothingSelector Selector = nothingSelector{}
+
 // Nothing returns a selector that matches no labels
 func Nothing() Selector {
-	return nothingSelector{}
+	return sharedNothingSelector
 }
 
 // NewSelector returns a nil selector

Original file line number	Diff line number	Diff line change
`@@ -74,9 +74,12 @@ type Selector interface {`
`74`	`74`	`RequiresExactMatch(label string) (value string, found bool)`
`75`	`75`	`}`
`76`	`76`
	`77`	`+// Sharing this saves 1 alloc per use; this is safe because it's immutable.`
	`78`	`+var sharedEverythingSelector Selector = internalSelector{}`
	`79`	`+`
`77`	`80`	`// Everything returns a selector that matches all labels.`
`78`	`81`	`func Everything() Selector {`
`79`		`- return internalSelector{}`
	`82`	`+ return sharedEverythingSelector`
`80`	`83`	`}`
`81`	`84`
`82`	`85`	`type nothingSelector struct{}`
`@@ -91,9 +94,12 @@ func (n nothingSelector) RequiresExactMatch(label string) (value string, found b`
`91`	`94`	`return "", false`
`92`	`95`	`}`
`93`	`96`
	`97`	`+// Sharing this saves 1 alloc per use; this is safe because it's immutable.`
	`98`	`+var sharedNothingSelector Selector = nothingSelector{}`
	`99`	`+`
`94`	`100`	`// Nothing returns a selector that matches no labels`
`95`	`101`	`func Nothing() Selector {`
`96`		`- return nothingSelector{}`
	`102`	`+ return sharedNothingSelector`
`97`	`103`	`}`
`98`	`104`
`99`	`105`	`// NewSelector returns a nil selector`