[$] A herd of migration discussions

Migration is the act of moving data from one location in physicalmemory to another. The kernel may migrate pages for many reasons,including defragmentation, improving NUMA locality, moving data to or frommemory hosted on a peripheral device, or freeing a range ofmemory for other uses. Given the importance of migration to thememory-management subsystem, there is a lot of interest in improving itsperformance and removing impediments to its success. Several sessions inthe memory-management track of the 2025 Linux Storage, Filesystem,Memory-Management, and BPF Summit were dedicated to this topic.