Merge pull request #17313 from danwinship/speed-up-ovs-healthcheck

Automatic merge from submit-queue.

Trivial fix to do fewer allocations in OVS healthcheck

Make `ovsController.AlreadySetUp()` scan the flows in reverse order; the flow we're looking for is in the highest-numbered table, and `ovs-ofctl dump-flows` returns the flows sorted by table number, so if we parse them in forward order, we'll end up unnecessarily parsing every single flow, while parsing them in reverse means we only parse one.

(Also stop parsing further flows once we found the one we were looking for, even if it has the wrong value.)

Fixes #17312

(We can also make improvements to ParseFlow itself later, but this just seemed like the simplest fix for the immediate problem.)

Author: openshift-merge-robot

pkg/network/node/ovscontroller.go

@@ -58,10 +58,11 @@ func (oc *ovsController) AlreadySetUp() bool {
 		return false
 	}
 	expectedVersionNote := oc.getVersionNote()
-	for _, flow := range flows {
-		parsed, err := ovs.ParseFlow(ovs.ParseForDump, flow)
-		if err == nil && parsed.Table == ruleVersionTable && parsed.NoteHasPrefix(expectedVersionNote) {
-			return true
+	// The "version" flow should be the last one, so scan from the end
+	for i := len(flows) - 1; i >= 0; i-- {
+		parsed, err := ovs.ParseFlow(ovs.ParseForDump, flows[i])
+		if err == nil && parsed.Table == ruleVersionTable {
+			return parsed.NoteHasPrefix(expectedVersionNote)
 		}
 	}
 	return false