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>
---
Documentation/filesystems/resctrl.rst | 8 ++++++++
fs/resctrl/ctrlmondata.c | 21 +++++++++++++++++----
2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index ba609f8d4de5..b003bed339fd 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -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
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 2ef53161ce11..9a7dfc48cb2e 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -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 @@ static int resctrl_io_alloc_parse_line(char *line, struct rdt_resource *r,
&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;
}
--
2.51.0Hi Aaron, On 3/24/26 5:11 PM, Aaron Tomlin wrote: > 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> > --- Thank you. Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reinette
The following commit has been merged into the x86/cache branch of tip:
Commit-ID: d2bf45d067c728b0fe6e8f99a7386b8291e391e3
Gitweb: https://git.kernel.org/tip/d2bf45d067c728b0fe6e8f99a7386b8291e391e3
Author: Aaron Tomlin <atomlin@atomlin.com>
AuthorDate: Tue, 24 Mar 2026 20:11:59 -04:00
Committer: Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 02 Apr 2026 00:22:59 +02:00
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
---
Documentation/filesystems/resctrl.rst | 8 ++++++++
fs/resctrl/ctrlmondata.c | 21 +++++++++++++++++----
2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index ba609f8..b003bed 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -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
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 2ef5316..9a7dfc4 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -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;
}© 2016 - 2026 Red Hat, Inc.