Memory System Resource Partitioning and Monitoring (MPAM) is an
optional extension to the Arm architecture that allows each
transaction issued to the memory system to be labelled with a
Partition identifier (PARTID) and Performance Monitoring Group
identifier (PMG).

Memory system components, such as the caches, can be configured with
policies to control how much of various physical resources (such as
memory bandwidth or cache memory) the transactions labelled with each
PARTID can consume. Depending on the capabilities of the hardware,
the PARTID and PMG can also be used as filtering criteria to measure
the memory system resource consumption of different parts of a
workload.

Use of this extension requires CPU support, support in the
Memory System Components (MSC), and a description from firmware
of where the MSCs are in the address space.

MPAM is exposed to user-space via the resctrl pseudo filesystem.

This option enables the extra context switch code.

source code:

arch/arm64/kernel/mpam.c