diff options
| author | Babu Moger <babu.moger@amd.com> | 2025-11-12 18:57:32 -0600 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-11-21 23:01:54 +0100 |
| commit | 9445c7059c1c3b097ec8e924eb374df84770bee5 (patch) | |
| tree | 83d3d6b8ee4db7ec66ea0c4f60e85584fbd26f3b /drivers/net/ethernet/intel/igc | |
| parent | 48068e565045ee0c77fdb34225ac6dedb5871fc2 (diff) | |
fs/resctrl: Add user interface to enable/disable io_alloc feature
AMD's SDCIAE forces all SDCI lines to be placed into the L3 cache portions
identified by the highest-supported L3_MASK_n register, where n is the maximum
supported CLOSID.
To support this, when io_alloc resctrl feature is enabled, reserve the highest
CLOSID exclusively for I/O allocation traffic making it no longer available for
general CPU cache allocation.
Introduce user interface to enable/disable io_alloc feature and encourage users
to enable io_alloc only when running workloads that can benefit from this
functionality. On enable, initialize the io_alloc CLOSID with all usable CBMs
across all the domains.
Since CLOSIDs are managed by resctrl fs, it is least invasive to make "io_alloc
is supported by maximum supported CLOSID" part of the initial resctrl fs
support for io_alloc. Take care to minimally (only in error messages) expose
this use of CLOSID for io_alloc to user space so that this is not required from
other architectures that may support io_alloc differently in the future.
When resctrl is mounted with "-o cdp" to enable code/data prioritization,
there are two L3 resources that can support I/O allocation: L3CODE and
L3DATA. From resctrl fs perspective the two resources share a CLOSID and
the architecture's available CLOSID are halved to support this.
The architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the
CLOSID associated with the CDP_CODE resource, but from resctrl's perspective
there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus not
usable for general (CPU) cache allocation nor I/O allocation.
Keep the CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion
to user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and
vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in sync.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://patch.msgid.link/c7d3037795e653e22b02d8fc73ca80d9b075031c.1762995456.git.babu.moger@amd.com
Diffstat (limited to 'drivers/net/ethernet/intel/igc')
0 files changed, 0 insertions, 0 deletions