[$] Improving the merging of anonymous VMAs

The virtual memory area (VMA), represented by structvm_area_struct, is one of the core abstractions of the kernel'smemory-management subsystem; a VMA represents a portion of a process'saddress space with the same characteristics. A memory-mapped file will berepresented by (at least) one VMA, as will the process's stack or a regionof anonymous memory. Efficiently managing VMAs and the logic around themis crucial for good performance overall. Lorenzo Stoakes focused on onespecific problem area: the merging of anonymous VMAs, during thememory-management track at the 2025 Linux Storage, Filesystem,Memory-Management, and BPF Summit.