Hi Reinette,
On 5/22/2025 4:02 PM, Reinette Chatre wrote:
Hi Babu,
shortlog: "at domain" -> "per domain"?
Sure.
On 5/15/25 3:51 PM, Babu Moger wrote:
In mbm_cntr_assign mode hardware counters are assigned/unassigned to an
MBM event of a monitor group. Hardware counters are assigned/unassigned
at monitoring domain level.
Manage a monitoring domain's hardware counters using a per monitoring
domain array of struct mbm_cntr_cfg that is indexed by the hardware
counter ID. A hardware counter's configuration contains the MBM event
ID and points to the monitoring group that it is assigned to, with a
NULL pointer meaning that the hardware counter is available for assignment.
There is no direct way to determine which hardware counters are assigned
to a particular monitoring group. Check every entry of every hardware
counter configuration array in every monitoring domain to query which
MBM events of a monitoring group is tracked by hardware. Such queries are
acceptable because of a very small number of assignable counters (32
to 64).
Suggested-by: Peter Newman <peternewman@xxxxxxxxxx>
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v13: Resolved conflicts caused by the recent FS/ARCH code restructure.
The files monitor.c/rdtgroup.c have been split between FS and ARCH directories.
v12: Fixed the struct mbm_cntr_cfg code documentation.
Removed few strange charactors in changelog.
Added the counter range for better understanding.
Moved the struct mbm_cntr_cfg definition to resctrl/internal.h as
suggested by James.
v11: Refined the change log based on Reinette's feedback.
Fixed few style issues.
v10: Patch changed completely to handle the counters at domain level.
https://lore.kernel.org/lkml/CALPaoCj+zWq1vkHVbXYP0znJbe6Ke3PXPWjtri5AFgD9cQDCUg@xxxxxxxxxxxxxx/
Removed Reviewed-by tag.
Did not see the need to add cntr_id in mbm_state structure. Not used in the code.
v9: Added Reviewed-by tag. No other changes.
v8: Minor commit message changes.
v7: Added check mbm_cntr_assignable for allocating bitmap mbm_cntr_map
v6: New patch to add domain level assignment.
---
fs/resctrl/rdtgroup.c | 11 +++++++++++
include/linux/resctrl.h | 16 ++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 51f8f8d3ccbc..e2005fc9acd9 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -4085,6 +4085,7 @@ static void rdtgroup_setup_default(void)
static void domain_destroy_mon_state(struct rdt_mon_domain *d)
{
+ kfree(d->cntr_cfg);
bitmap_free(d->rmid_busy_llc);
kfree(d->mbm_total);
kfree(d->mbm_local);
@@ -4171,6 +4172,16 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_mon_domain
return -ENOMEM;
}
}
+ if (resctrl_is_mbm_enabled() && r->mon.mbm_cntr_assignable) {
+ tsize = sizeof(*d->cntr_cfg);
+ d->cntr_cfg = kcalloc(r->mon.num_mbm_cntrs, tsize, GFP_KERNEL);
+ if (!d->cntr_cfg) {
+ bitmap_free(d->rmid_busy_llc);
+ kfree(d->mbm_total);
+ kfree(d->mbm_local);
+ return -ENOMEM;
+ }
+ }
return 0;
}
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index bdb264875ef6..d77981d1fcb9 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -156,6 +156,20 @@ struct rdt_ctrl_domain {
u32 *mbps_val;
};
+/**
+ * struct mbm_cntr_cfg - Assignable counter configuration
+ * @evtid: MBM event to which the counter is assigned. Only valid
+ * if @rdtgroup is not NULL.
+ * @evt_cfg: Event configuration value.
@evt_cfg is not introduced in changelog nor defined here. Please add a snippet here
on what @evt_cfg's values represent. This is important since this is exposed
as resctrl fs API to architectures so all architectures need to use same values when
interacting with resctrl.
Sure.
@evt_cfg: A value that represents memory transactions (e.g., reads,
writes, etc.).
+ * @rdtgrp: resctrl group assigned to the counter. NULL if the
+ * counter is free.
+ */
+struct mbm_cntr_cfg {
+ enum resctrl_event_id evtid;
+ u32 evt_cfg;
+ struct rdtgroup *rdtgrp;
Please align struct member names using TABs.
Sure.
+};
+
/**
* struct rdt_mon_domain - group of CPUs sharing a resctrl monitor resource
* @hdr: common header for different domain types
@@ -167,6 +181,7 @@ struct rdt_ctrl_domain {
* @cqm_limbo: worker to periodically read CQM h/w counters
* @mbm_work_cpu: worker CPU for MBM h/w counters
* @cqm_work_cpu: worker CPU for CQM h/w counters
+ * @cntr_cfg: assignable counters configuration
"array of assignable counters' configuration (indexed by counter ID)"
Sure.
*/
struct rdt_mon_domain {
struct rdt_domain_hdr hdr;
@@ -178,6 +193,7 @@ struct rdt_mon_domain {
struct delayed_work cqm_limbo;
int mbm_work_cpu;
int cqm_work_cpu;
+ struct mbm_cntr_cfg *cntr_cfg;
};
/**
Reinette
thanks
Babu
