Function assign_partition_chunks 

fn assign_partition_chunks(
    domain: &Cpumask,
    counts: &[(u32, usize)],
    cpu_to_partition: &HashMap<usize, usize>,
) -> Result<HashMap<u32, Cpumask>>

Place the per-recipient CPU counts onto domain by partition chunk. The recipient with the most CPUs left takes the largest chunk that still fits, so each recipient collects whole partitions first; whatever counts remain are carved contiguously from the chunks nobody could take whole. counts must sum to the domain size.