Allow caching based on a configurable number of hits. (#8891)

Co-authored-by: Harshavardhana <harsha@minio.io>

cmd/config/cache/config.go

@@ -34,6 +34,7 @@ type Config struct {
 	MaxUse  int      `json:"maxuse"`
 	Quota   int      `json:"quota"`
 	Exclude []string `json:"exclude"`
+	After   int      `json:"after"`
 }
 
 // UnmarshalJSON - implements JSON unmarshal interface for unmarshalling
@@ -60,7 +61,9 @@ func (cfg *Config) UnmarshalJSON(data []byte) (err error) {
 	if _cfg.Quota < 0 {
 		return errors.New("config quota value should not be null or negative")
 	}
-
+	if _cfg.After < 0 {
+		return errors.New("cache after value should not be less than 0")
+	}
 	return nil
 }