I have a task to disable CPU hotplug in RHEL5 kernel (2.6.18-el5.xxx). I have no problem recompiling an own kernel from the sources with an old config.
But as soon as I disable CPU hotplug, I get kernel panic during the boot, every boot with a different error codes.
So, is there any way to disable CPU hotplug on 2.6.18-el5? Or any other method to spread iowait between the CPUs in system? Our developers read somewhere that disabling CPU hotplug allows Linux kernel to do it. But how to turn a hotplug off?
It seems the CPU hotplug is not a feature but a requirement for the Linux kernel to work properly...