[PATCH 20/21] x86/intel_rdt/mbm: Add mbm counter initialization

[Vikas Shivappa]

MBM counters are monotonically increasing counts representing the total
memory bytes at a particular time. In order to calculate total_bytes for
an rdtgroup, we store the value of the counter when we create an
rdtgroup or when a new domain comes online.

When the total_bytes(all memory controller bytes) or local_bytes(local
memory controller bytes) file in "mon_data" is read it shows the total
bytes for that rdtgroup since its creation. User can snapshot this at
different time intervals to obtain bytes/second.

Signed-off-by: Vikas Shivappa <vikas.shivappa@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/intel_rdt.c             |  2 +-
 arch/x86/kernel/cpu/intel_rdt.h             | 11 +++++++++-
 arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 25 +++++++++++++--------
 arch/x86/kernel/cpu/intel_rdt_monitor.c     |  7 ++++++
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c    | 34 ++++++++++++++++++-----------
 5 files changed, 55 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index a17f323..7762e32 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -469,7 +469,7 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
 	 * per domain monitor data directories.
 	 */
 	if (static_branch_unlikely(&rdt_mon_enable_key))
-		mkdir_mondata_subdir_allrdtgrp(r, d->id);
+		mkdir_mondata_subdir_allrdtgrp(r, d);
 }
 
 static void domain_remove_cpu(int cpu, struct rdt_resource *r)
diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index ab010fb..f0896ac 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -57,6 +57,7 @@ struct rmid_read {
 	struct rdtgroup		*rgrp;
 	struct rdt_domain	*d;
 	int			evtid;
+	bool			first;
 	u64			val;
 };
 
@@ -253,6 +254,12 @@ static inline bool is_mbm_enabled(void)
 	return (is_mbm_total_enabled() || is_mbm_local_enabled());
 }
 
+static inline bool is_mbm_event(int e)
+{
+	return (e >= QOS_L3_MBM_TOTAL_EVENT_ID &&
+		e <= QOS_L3_MBM_LOCAL_EVENT_ID);
+}
+
 /**
  * struct rdt_resource - attributes of an RDT resource
  * @alloc_enabled:	Is allocation enabled on this machine
@@ -390,6 +397,8 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of,
 void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
 				    unsigned int dom_id);
 void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
-				    unsigned int dom_id);
+				    struct rdt_domain *d);
+void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
+		    struct rdtgroup *rdtgrp, int evtid, int first);
 
 #endif /* _ASM_X86_INTEL_RDT_H */
diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
index 926d889..e9391e3 100644
--- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
@@ -285,6 +285,21 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
+		    struct rdtgroup *rdtgrp, int evtid, int first)
+{
+	/*
+	 * setup the parameters to send to the IPI to read the data.
+	 */
+	rr->rgrp = rdtgrp;
+	rr->evtid = evtid;
+	rr->d = d;
+	rr->val = 0;
+	rr->first = first;
+
+	smp_call_function_any(&d->cpu_mask, mon_event_count, rr, 1);
+}
+
 int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 {
 	struct kernfs_open_file *of = m->private;
@@ -310,15 +325,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 		goto out;
 	}
 
-	/*
-	 * setup the parameters to send to the IPI to read the data.
-	 */
-	rr.rgrp = rdtgrp;
-	rr.evtid = evtid;
-	rr.d = d;
-	rr.val = 0;
-
-	smp_call_function_any(&d->cpu_mask, mon_event_count, &rr, 1);
+	mon_event_read(&rr, d, rdtgrp, evtid, false);
 
 	if (rr.val & RMID_VAL_ERROR)
 		seq_puts(m, "Error\n");
diff --git a/arch/x86/kernel/cpu/intel_rdt_monitor.c b/arch/x86/kernel/cpu/intel_rdt_monitor.c
index 2c5768c..a196f4d 100644
--- a/arch/x86/kernel/cpu/intel_rdt_monitor.c
+++ b/arch/x86/kernel/cpu/intel_rdt_monitor.c
@@ -230,6 +230,13 @@ static bool __mon_event_count(u32 rmid, struct rmid_read *rr)
 	default:
 		return false;
 	}
+
+	if (rr->first) {
+		m->prev_msr = tval;
+		m->chunks = 0;
+		return true;
+	}
+
 	shift = 64 - MBM_CNTR_WIDTH;
 	chunks = (tval << shift) - (m->prev_msr << shift);
 	chunks >>= shift;
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 8e1581a..1b84485 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1379,12 +1379,14 @@ static int get_rdt_resourceid(struct rdt_resource *r)
 	return ((r - rdt_resources_all) / sizeof(struct rdt_resource));
 }
 
-static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, int domid,
+static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
+				struct rdt_domain *d,
 				struct rdt_resource *r, struct rdtgroup *pr)
 {
 	union mon_data_bits priv;
 	struct kernfs_node *kn;
 	struct mon_evt *mevt;
+	struct rmid_read rr;
 	char name[32];
 	int ret, rid;
 
@@ -1392,7 +1394,7 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, int domid,
 	if (rid < 0)
 		return -EINVAL;
 
-	sprintf(name, "mon_%s_%02d", r->name, domid);
+	sprintf(name, "mon_%s_%02d", r->name, d->id);
 	/* create the directory */
 	kn = kernfs_create_dir(parent_kn, name, parent_kn->mode, pr);
 	if (IS_ERR(kn))
@@ -1413,12 +1415,15 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, int domid,
 	}
 
 	priv.u.rid = rid;
-	priv.u.domid = domid;
+	priv.u.domid = d->id;
 	list_for_each_entry(mevt, &r->evt_list, list) {
 		priv.u.evtid = mevt->evtid;
 		ret = mon_addfile(kn, mevt->name, priv.priv);
 		if (ret)
 			goto out_destroy;
+
+		if (is_mbm_event(mevt->evtid))
+			mon_event_read(&rr, d, pr, mevt->evtid, true);
 	}
 	kernfs_activate(kn);
 	return 0;
@@ -1432,7 +1437,8 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn, int domid,
  * Add all subdirectories of mon_data for "ctrl_mon" groups
  * and "monitor" groups with given domain id.
  */
-void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int domid)
+void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
+				    struct rdt_domain *d)
 {
 	struct kernfs_node *parent_kn;
 	struct rdtgroup *pr, *cr;
@@ -1442,11 +1448,11 @@ void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r, unsigned int domid)
 
 	list_for_each_entry(pr, &rdt_all_groups, rdtgroup_list) {
 		parent_kn = pr->mon_data_kn;
-		mkdir_mondata_subdir(parent_kn, domid, r, pr);
+		mkdir_mondata_subdir(parent_kn, d, r, pr);
 
 		list_for_each_entry(cr, &pr->crdtgrp_list, crdtgrp_list) {
 			parent_kn = cr->mon_data_kn;
-			mkdir_mondata_subdir(parent_kn, domid, r, cr);
+			mkdir_mondata_subdir(parent_kn, d, r, cr);
 		}
 	}
 }
@@ -1459,7 +1465,7 @@ static int mkdir_mondata_subdir_alldom(struct kernfs_node *parent_kn,
 	int ret;
 
 	list_for_each_entry(dom, &r->domains, list) {
-		ret = mkdir_mondata_subdir(parent_kn, dom->id, r, pr);
+		ret = mkdir_mondata_subdir(parent_kn, dom, r, pr);
 		if (ret)
 			return ret;
 	}
@@ -1575,20 +1581,22 @@ static int mkdir_rdt_common(struct kernfs_node *pkn, struct kernfs_node *prkn,
 		goto out_destroy;
 
 	if (rdt_mon_features) {
-		ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon_data_kn);
-		if (ret)
-			goto out_destroy;
-
 		ret = alloc_rmid();
 		if (ret < 0)
-			return ret;
-
+			goto out_destroy;
 		rdtgrp->rmid = ret;
+
+		ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon_data_kn);
+		if (ret)
+			goto out_idfree;
 	}
 	kernfs_activate(kn);
 
 	return 0;
 
+out_idfree:
+	if (rdtgrp->rmid)
+		free_rmid(rdtgrp->rmid);
 out_destroy:
 	kernfs_remove(rdtgrp->kn);
 out_cancel_ref:
-- 
1.9.1