Chapter 16. Kernel

sched_ext scheduler for creating a custom scheduler

In RHEL 10, with sched_ext you can create custom process scheduling code in extended Berkeley Packet Filter (eBPF) at runtime. The sched_ext scheduler allows you to replace the standard kernel scheduler with your own scheduling logic to control process prioritization, resource allocation, and execution behavior.

CFS is replaced with the EEVDF scheduler

The Completely Fair Scheduler (CFS) is replaced with a new scheduler, Enhanced Earliest Deadline First (EEVDF). This includes the following changes:

Secure Boot shim signing for RHEL 10 on x86_64 and aarch64

Red Hat Enterprise Linux (RHEL) 10 requires a signed shim binary to support Secure Boot on x86_64 and aarch64 architectures. The shim functions as the initial bootloader, verifying and loading subsequent boot components if you enabled Secure Boot. If a signed and trusted shim is not available, RHEL 10 cannot boot on systems with Secure Boot enforced. This limitation might affect deployments in enterprise and cloud environments.