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fs/resctrl: Add "*" shorthand to set io_alloc CBM for all domains 

Configuring the io_alloc_cbm interface requires an explicit domain ID for each
cache domain. On systems with high core counts and numerous cache clusters,
this requirement becomes cumbersome for automation and management tasks that
aim to apply a uniform policy.

Introduce a wildcard domain ID selector "*" for the io_alloc_cbm interface.
This enables users to set the same Capacity Bitmask (CBM) across all cache
domains in a single operation.

Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://patch.msgid.link/20260325001159.447075-3-atomlin@atomlin.com
master
Aaron Tomlin 2026-03-24 20:11:59 -04:00 committed by Borislav Petkov (AMD)
parent d06b8e7c97
commit d2bf45d067
2 changed files with 25 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/filesystems/resctrl.rst
View File

@ -215,6 +215,14 @@ related to allocation:
# cat /sys/fs/resctrl/info/L3/io_alloc_cbm
0=00ff;1=000f
An ID of "*" configures all domains with the provided CBM.
Example on a system that does not require a minimum number of consecutive bits in the mask::
# echo "*=0" > /sys/fs/resctrl/info/L3/io_alloc_cbm
# cat /sys/fs/resctrl/info/L3/io_alloc_cbm
0=0;1=0
When CDP is enabled "io_alloc_cbm" associated with the CDP_DATA and CDP_CODE
resources may reflect the same values. For example, values read from and
written to /sys/fs/resctrl/info/L3DATA/io_alloc_cbm may be reflected by

21
fs/resctrl/ctrlmondata.c
View File

@ -954,25 +954,34 @@ static int resctrl_io_alloc_parse_line(char *line, struct rdt_resource *r,
struct resctrl_schema *s, u32 closid)
{
enum resctrl_conf_type peer_type;
unsigned long dom_id = ULONG_MAX;
struct rdt_parse_data data;
struct rdt_ctrl_domain *d;
bool update_all = false;
char *dom = NULL, *id;
unsigned long dom_id;
next:
if (!line || line[0] == '\0')
return 0;
if (update_all) {
rdt_last_cmd_puts("Configurations after global '*'\n");
return -EINVAL;
}
dom = strsep(&line, ";");
id = strsep(&dom, "=");
if (!dom || kstrtoul(id, 10, &dom_id)) {
if (dom && !strcmp(id, "*")) {
update_all = true;
} else if (!dom || kstrtoul(id, 10, &dom_id)) {
rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");
return -EINVAL;
}
dom = strim(dom);
list_for_each_entry(d, &r->ctrl_domains, hdr.list) {
if (d->hdr.id == dom_id) {
if (update_all || d->hdr.id == dom_id) {
data.buf = dom;
data.mode = RDT_MODE_SHAREABLE;
data.closid = closid;
@ -988,10 +997,14 @@ next:
&d->staged_config[s->conf_type],
sizeof(d->staged_config[0]));
}
goto next;
if (!update_all)
goto next;
}
}
if (update_all)
goto next;
rdt_last_cmd_printf("Invalid domain %lu\n", dom_id);
return -EINVAL;
}