[PATCH RFC v1 5/6] arm_mpam: Add MB_MAXHLM_NODE and Node scope
From: Fenghua Yu
Date: Mon Nov 09 2026 - 16:33:48 EST
Memory-level MSCs expose their domains as NUMA nodes, so their
hard-limit control must be named MB_MAXHLM_NODE rather than MB_MAXHLM.
Add RESCTRL_CTRL_NAME_MAXHLM_NODE and create it for memory classes.
Set the MBA resource ctrl_scope to RESCTRL_NODE for those classes.
Add resctrl_ctrl_maxhlm() so the schemata parser, group setup, default
value, and resctrl_arch_get_config()/resctrl_arch_update_one() accept
both hard-limit names.
The hard-limit control is a 0/1 HARDLIM toggle. Set its scalar range
to 0..1 with a reset value of 0 instead of inheriting the bandwidth
percentage range.
Signed-off-by: Fenghua Yu <fenghuay@xxxxxxxxxx>
---
drivers/resctrl/mpam_resctrl.c | 47 ++++++++++++++++++++++++++++++----
fs/resctrl/ctrlmondata.c | 3 ++-
fs/resctrl/rdtgroup.c | 2 +-
include/linux/resctrl.h | 12 +++++++--
4 files changed, 55 insertions(+), 9 deletions(-)
diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index ea1fb7fc7e01..f1325ffb6343 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -1266,10 +1266,14 @@ void resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_l3_mon_domain *
resctrl_arch_reset_cntr(r, d, closid, rmid, cntr_id, evtid);
}
-static void _mpam_resctrl_ctrl_init_mba(struct mpam_resctrl_ctrl *mpam_ctrl,
+static void _mpam_resctrl_ctrl_init_mba(struct rdt_resource *r,
+ struct mpam_resctrl_ctrl *mpam_ctrl,
struct mpam_props *cprops,
enum resctrl_ctrl_name name)
{
+ struct mpam_resctrl_res *res;
+ struct mpam_class *class;
+
mpam_ctrl->r_ctrl.type = RESCTRL_CTRL_SCALAR;
mpam_ctrl->r_ctrl.name = name;
INIT_LIST_HEAD_RCU(&mpam_ctrl->r_ctrl.domains);
@@ -1287,6 +1291,35 @@ static void _mpam_resctrl_ctrl_init_mba(struct mpam_resctrl_ctrl *mpam_ctrl,
mpam_ctrl->r_ctrl.scalar.gran = get_mba_granularity(cprops);
__set_bit(RESCTRL_SCALAR_FLAG_LINEAR, mpam_ctrl->r_ctrl.scalar.flags);
+
+ /*
+ * The hard-limit control is a 0/1 HARDLIM toggle. It must not
+ * inherit the bandwidth percentage range.
+ */
+ if (resctrl_ctrl_maxhlm(&mpam_ctrl->r_ctrl)) {
+ mpam_ctrl->r_ctrl.scalar.min = 0;
+ mpam_ctrl->r_ctrl.scalar.max = 1;
+ mpam_ctrl->r_ctrl.scalar.reset_val = 0;
+ mpam_ctrl->r_ctrl.scalar.gran = 1;
+ }
+
+ res = container_of(r, struct mpam_resctrl_res, resctrl_res);
+ class = res->class;
+ if (mpam_class_memory(class))
+ r->ctrl_scope = RESCTRL_NODE;
+}
+
+static enum resctrl_ctrl_name get_ctrl_name_maxhlm(struct rdt_resource *r)
+{
+ struct mpam_resctrl_res *res;
+ struct mpam_class *class;
+
+ res = container_of(r, struct mpam_resctrl_res, resctrl_res);
+ class = res->class;
+ if (mpam_class_memory(class))
+ return RESCTRL_CTRL_NAME_MAXHLM_NODE;
+
+ return RESCTRL_CTRL_NAME_MAXHLM;
}
static int mpam_resctrl_ctrl_init_mba(struct rdt_resource *r,
@@ -1305,10 +1338,10 @@ static int mpam_resctrl_ctrl_init_mba(struct rdt_resource *r,
res = container_of(r, struct mpam_resctrl_res, resctrl_res);
class = res->class;
if (mpam_class_memory(class)) {
- _mpam_resctrl_ctrl_init_mba(mpam_ctrl, cprops,
+ _mpam_resctrl_ctrl_init_mba(r, mpam_ctrl, cprops,
RESCTRL_CTRL_NAME_NODE);
} else {
- _mpam_resctrl_ctrl_init_mba(mpam_ctrl, cprops,
+ _mpam_resctrl_ctrl_init_mba(r, mpam_ctrl, cprops,
RESCTRL_CTRL_NAME_DEF);
}
@@ -1318,14 +1351,16 @@ static int mpam_resctrl_ctrl_init_mba(struct rdt_resource *r,
* this fails.
*/
if (mpam_has_feature(mpam_feat_mbw_max_hardlim_rw, cprops)) {
+ enum resctrl_ctrl_name name;
+
ctrl_maxhlm = kzalloc_obj(*ctrl_maxhlm);
if (!ctrl_maxhlm) {
kfree(mpam_ctrl);
return -ENOMEM;
}
- _mpam_resctrl_ctrl_init_mba(ctrl_maxhlm, cprops,
- RESCTRL_CTRL_NAME_MAXHLM);
+ name = get_ctrl_name_maxhlm(r);
+ _mpam_resctrl_ctrl_init_mba(r, ctrl_maxhlm, cprops, name);
}
/*
@@ -1588,6 +1623,7 @@ u32 resctrl_arch_get_config(struct rdt_resource *r, struct resctrl_ctrl *ctrl,
configured_by = mpam_feat_mbw_max;
break;
case RESCTRL_CTRL_NAME_MAXHLM:
+ case RESCTRL_CTRL_NAME_MAXHLM_NODE:
configured_by = mpam_feat_mbw_max_hardlim_rw;
break;
default:
@@ -1671,6 +1707,7 @@ int resctrl_arch_update_one(struct rdt_resource *r, struct resctrl_ctrl *ctrl,
}
return -EINVAL;
case RESCTRL_CTRL_NAME_MAXHLM:
+ case RESCTRL_CTRL_NAME_MAXHLM_NODE:
if (mpam_has_feature(mpam_feat_mbw_max_hardlim_rw, cprops) &&
mpam_has_feature(mpam_feat_mbw_max, cprops)) {
/*
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index 9111b0130783..352a3f847b4b 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -189,7 +189,7 @@ static int parse_bw(struct rdt_parse_data *data, struct rdt_resource_final *f,
}
/* Parse mb_maxhlm line */
- if (ctrl->name == RESCTRL_CTRL_NAME_MAXHLM) {
+ if (resctrl_ctrl_maxhlm(ctrl)) {
if (!mb_maxhlm_validate(data->buf, &bw_val, r, ctrl))
return -EINVAL;
@@ -397,6 +397,7 @@ static const char * const resctrl_ctrl_name[] = {
[RESCTRL_CTRL_NAME_REGION0_MIN] = "REGION0_MIN",
[RESCTRL_CTRL_NAME_REGION0_MAX] = "REGION0_MAX",
[RESCTRL_CTRL_NAME_MAXHLM] = "MAXHLM",
+ [RESCTRL_CTRL_NAME_MAXHLM_NODE] = "MAXHLM_NODE",
};
const char *resctrl_ctrl_name_str(enum resctrl_ctrl_name name)
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 01e69d0d9e96..1a6dbad15fd5 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -4429,7 +4429,7 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
for_each_enabled_ctrl(ctrl, r) {
if (r->rid == RDT_RESOURCE_MBA ||
r->rid == RDT_RESOURCE_SMBA) {
- if (ctrl->name == RESCTRL_CTRL_NAME_MAXHLM) {
+ if (resctrl_ctrl_maxhlm(ctrl)) {
rdtgroup_init_mb_hlim(ctrl);
continue;
}
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 5711154145f8..1c75ac68d68f 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -403,6 +403,7 @@ struct resctrl_mon {
* @RESCTRL_CTRL_NAME_REGION0_MIN: "REGION0_MIN"
* @RESCTRL_CTRL_NAME_REGION0_MAX: "REGION0_MAX"
* @RESCTRL_CTRL_NAME_MAXHLM: "MAXHLM"
+ * @RESCTRL_CTRL_NAME_MAXHLM_NODE:"MAXHLM_NODE"
*/
enum resctrl_ctrl_name {
RESCTRL_CTRL_NAME_DEF,
@@ -412,7 +413,8 @@ enum resctrl_ctrl_name {
RESCTRL_CTRL_NAME_REGION0_MIN,
RESCTRL_CTRL_NAME_REGION0_MAX,
RESCTRL_CTRL_NAME_MAXHLM,
- RESCTRL_CTRL_NAME_LAST = RESCTRL_CTRL_NAME_MAXHLM
+ RESCTRL_CTRL_NAME_MAXHLM_NODE,
+ RESCTRL_CTRL_NAME_LAST = RESCTRL_CTRL_NAME_MAXHLM_NODE
};
/**
@@ -603,6 +605,12 @@ int resctrl_arch_control_mode_set(struct rdt_resource *r,
*/
void resctrl_arch_sync_cpu_closid_rmid(void *info);
+static inline bool resctrl_ctrl_maxhlm(struct resctrl_ctrl *ctrl)
+{
+ return ctrl->name == RESCTRL_CTRL_NAME_MAXHLM ||
+ ctrl->name == RESCTRL_CTRL_NAME_MAXHLM_NODE;
+}
+
/**
* resctrl_get_default_ctrlval() - Return the default control value for this
* control.
@@ -619,7 +627,7 @@ static inline u32 resctrl_get_default_ctrlval(struct resctrl_ctrl *ctrl)
return BIT_MASK(ctrl->bitmap.cbm_len) - 1;
case RESCTRL_CTRL_SCALAR:
/* The hard-limit toggle defaults to off. */
- if (ctrl->name == RESCTRL_CTRL_NAME_MAXHLM)
+ if (resctrl_ctrl_maxhlm(ctrl))
return 0;
return ctrl->scalar.reset_val;
--
2.53.0