Post Syndicated from original https://lwn.net/Articles/902094/

A 64-bit pointer can address a lot of memory — far more than just about any
application could ever need. As a result, there are bits within that pointer that
are not really needed to address memory, and which might be put to other
needs. Storing a few bits of metadata within a pointer is a common enough
use case that multiple architectures are adding support for it at the
hardware level. Intel is no exception; support for its “Linear Address
Masking” (LAM) feature has been slowly making its way toward the mainline
kernel.