[$] A pair of memory-allocation improvements in 5.13

Among the many changes merged for 5.13 can be found performance
improvements throughout the kernel. This work does not always stand out
the way that new features do, but it is vitally important for the future of
the kernel overall. In the memory-management area, a couple of
long-running patch sets have finally made it into the mainline; these
provide a bulk page-allocation interface and
huge-page mappings in the vmalloc() area.
Both of these changes should make things faster, at least for some
workloads.