Function plan_llcs 

pub fn plan_llcs(
    cpu_to_llc: &[(u32, u32)],
    primary_cpus: &[u32],
    max_llcs: usize,
) -> LlcPlan

Build the LLC plan from a synthetic (cpu, llc) map.

LLC ids are expected to be dense (0-based). An empty map, or a map with more domains than max_llcs, disables LLC awareness entirely so the BPF side falls back to the current placement behavior. Every CPU the map does not cover (unknown or out of range) keeps the MLFQ_MAX_LLCS sentinel, never the 0 of a valid domain, so an unmapped CPU can never be attributed to LLC 0.