We should discuss a new approach for increasing KVM virtual CPU (vCPU) priority when guests need low latency. The last RFC posting [1] on this is thought to be too rigid and baking too much policy into the kernel. Incorporating complex policy logic directly into KVM seems problematic long-term for maintenance. Lets discuss leveraging BPF programs to offload more scheduling policy decisions to BPF / userspace. Specific issues to discuss: * Add support for enabling BPF programs to share memory and interface with guest. * Create a kernel function allowing BPF programs to call sched_setscheduler(), facilitating priority boosting. * UAPI concerns. * Challenges with loading BPF programs in guest userspace we don't control. [1] https://lore.kernel.org/all/20231214024727.3503870-1-vineeth@xxxxxxxxxxxxxxx/
