1. A computer-implemented method comprising: evaluating, in a multi-platform system that comprises a plurality of logical partitions, a candidacy of a plurality of processes executing in a first platform of the system for migration to a second platform of the system, wherein the first platform comprises a first operating system executing in the first logical partition, and the second platform comprises a different, second operating system executing in the second logical partition of the plurality of logical partitions; based at least on evaluating the candidacy of the plurality of processes, selecting a subset of the processes to be migrated from the first platform to the second platform; determining a cost of migrating each of the processes of the subset; determining a migration priority of each of the processes of the subset based at least on the respective cost of migration of each process of the subset; and migrating a particular process of the subset from the first platform to the second platform in an order that is based at least on the migration priority of the particular process.