[PATCH v2 0/3] x86/resctrl: Add "*" shorthand to set minimum io_alloc CBM for all domains

Aaron Tomlin
2025-12-15T23:03:07Z

Hi Babu, Tony, Reinette,

This series was rebased on linus/master since commit 187d0801404f (tag
v6.18-12991-g187d0801404f).

As previously discussed [1], a special domain ID selector "*" has been
introduced for io_alloc_cbm that allows setting the CBM of each cache
domain to its minimum number of consecutive bits in a single operation. For
example, writing "*=0" to /sys/fs/resctrl/info/L3/io_alloc_cbm programs
each domain's CBM to the hardware-defined minimum, greatly simplifying
automation and management tasks. The user is required to specify the
correct minimum stored in /sys/fs/resctrl/info/L3/min_cbm_bits.

Please let me know your thoughts.

[1]: https://lore.kernel.org/lkml/7e117908-41ae-4f42-8863-1361101c33ab@amd.com/

Changes since v1 [2]:

- Updated each helper for consistency (Babu Moger)
- Refactored the loop logic in function resctrl_io_alloc_parse_line()
to improve readability
- Added inline keyword to each helper
- Added inline keyword to function parse_domain_cbm()

[2]: https://lore.kernel.org/lkml/20251126171653.1004321-1-atomlin@atomlin.com/

Aaron Tomlin (3):
fs/resctrl: Add helpers to check io_alloc support and enabled state
fs/resctrl: Return -EINVAL for a missing seq_show implementation
x86/resctrl: Add "*" shorthand to set minimum io_alloc CBM for all
domains

Documentation/filesystems/resctrl.rst | 10 +
arch/x86/kernel/cpu/resctrl/core.c | 2 +-
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 23 ++-
fs/resctrl/ctrlmondata.c | 215 ++++++++++++++++------
fs/resctrl/internal.h | 13 ++
fs/resctrl/rdtgroup.c | 5 +-
include/linux/resctrl.h | 30 ++-
7 files changed, 230 insertions(+), 68 deletions(-)

--
2.51.0