We want to propose a way to upgrade a kernel on a machine without
restarting all the user-space services. This is to be done with CRIU
project, but we need help from the kernel to preserve some data in
memory while doing kexec.
The key point of our implementation is leaving process memory in-place
during reboot. This should eliminate most io operations the services
would produce during initialization. To achieve this, we have
implemented a pseudo file system that preserves its content during
kexec. We propose saving CRIU dump files to this file system, kexec'ing
and then restoring the processes in the newly booted kernel.