Linux 5.15 Addressing Scalability Issue That Caused Huge IBM Servers 30+ Minutes To Boot

Very large IBM mainframes/servers were taking 30+ minutes to boot the Linux kernel... No, just not for POST'ing the system with memory training and the like, but for loading Linux. Fortunately, with the Linux 5.15 kernel there is a set of scalability enhancements to allow these large IBM systems to be able to boot in around five minutes...