[PATCH v8 17/25] x86/resctrl: Add the interface to assign/update counter assignment

[Babu Moger]

The mbm_cntr_assign mode offers several hardware counters that can be
assigned to an RMID-event pair and monitor the bandwidth as long as it
is assigned.

Counters are managed at two levels. The global assignment is tracked
using the mbm_cntr_free_map field in the struct resctrl_mon, while
domain-specific assignments are tracked using the mbm_cntr_map field
in the struct rdt_mon_domain. Allocation begins at the global level
and is then applied individually to each domain.

Introduce an interface to allocate these counters and update the
corresponding domains accordingly.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v8: Renamed rdtgroup_assign_cntr() to rdtgroup_assign_cntr_event().
    Added the code to return the error if rdtgroup_assign_cntr_event fails.
    Moved definition of MBM_EVENT_ARRAY_INDEX to resctrl/internal.h.
    Updated typo in the comments.

v7: New patch. Moved all the FS code here.
    Merged rdtgroup_assign_cntr and rdtgroup_alloc_cntr.
    Adde new #define MBM_EVENT_ARRAY_INDEX.
---
 arch/x86/kernel/cpu/resctrl/internal.h |  9 +++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 47 ++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 6d4df0490186..900e18aea2c4 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -67,6 +67,13 @@
 
 #define MON_CNTR_UNSET			U32_MAX
 
+/*
+ * Get the counter index for the assignable counter
+ * 0 for evtid == QOS_L3_MBM_TOTAL_EVENT_ID
+ * 1 for evtid == QOS_L3_MBM_LOCAL_EVENT_ID
+ */
+#define MBM_EVENT_ARRAY_INDEX(_event) ((_event) - 2)
+
 /**
  * cpumask_any_housekeeping() - Choose any CPU in @mask, preferring those that
  *			        aren't marked nohz_full
@@ -708,6 +715,8 @@ unsigned int mon_event_config_index_get(u32 evtid);
 int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
 			     enum resctrl_event_id evtid, u32 rmid, u32 closid,
 			     u32 cntr_id, bool assign);
+int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+			       struct rdt_mon_domain *d, enum resctrl_event_id evtid);
 void rdt_staged_configs_clear(void);
 bool closid_allocated(unsigned int closid);
 int resctrl_find_cleanest_closid(void);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 4ab1a18010c9..e4f628e6fe65 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1898,6 +1898,53 @@ int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
 	return 0;
 }
 
+/*
+ * Assign a hardware counter to the group.
+ * Counter will be assigned to all the domains if rdt_mon_domain is NULL
+ * else the counter will be allocated to specific domain.
+ */
+int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
+			       struct rdt_mon_domain *d, enum resctrl_event_id evtid)
+{
+	int index = MBM_EVENT_ARRAY_INDEX(evtid);
+	int cntr_id = rdtgrp->mon.cntr_id[index];
+	int ret;
+
+	/*
+	 * Allocate a new counter id to the event if the counter is not
+	 * assigned already.
+	 */
+	if (cntr_id == MON_CNTR_UNSET) {
+		cntr_id = mbm_cntr_alloc(r);
+		if (cntr_id < 0) {
+			rdt_last_cmd_puts("Out of MBM assignable counters\n");
+			return -ENOSPC;
+		}
+		rdtgrp->mon.cntr_id[index] = cntr_id;
+	}
+
+	if (!d) {
+		list_for_each_entry(d, &r->mon_domains, hdr.list) {
+			ret = resctrl_arch_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
+						       rdtgrp->closid, cntr_id, true);
+			if (ret)
+				goto out_done_assign;
+
+			set_bit(cntr_id, d->mbm_cntr_map);
+		}
+	} else {
+		ret = resctrl_arch_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
+					       rdtgrp->closid, cntr_id, true);
+		if (ret)
+			goto out_done_assign;
+
+		set_bit(cntr_id, d->mbm_cntr_map);
+	}
+
+out_done_assign:
+	return ret;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_common_files[] = {
 	{
-- 
2.34.1