question: public static IgniteLogger logger ( GridKernalContext ctx , AtomicReference < IgniteLogger > logRef , Class < ? > cls ) { IgniteLogger log = logRef . get ( ) ; if ( log == null ) { logRef . compareAndSet ( null , ctx . log ( cls ) ) ; log = logRef . get ( ) ; } return log ; }
target:  Initializes logger into/from log reference passed in.