x86/intel_rdt/mbm: Add mbm counter initialization

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@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-28-git-send-email-vikas.shivappa@linux.intel.com

arch/x86/kernel/cpu/intel_rdt.h

@@ -55,6 +55,7 @@ struct rmid_read {
 	struct rdtgroup		*rgrp;
 	struct rdt_domain	*d;
 	int			evtid;
+	bool			first;
 	u64			val;
 };
 
@@ -263,6 +264,12 @@ 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
  * @rid:		The index of the resource
@@ -402,5 +409,7 @@ void rmdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
 				    unsigned int dom_id);
 void mkdir_mondata_subdir_allrdtgrp(struct rdt_resource *r,
 				    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 */

arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c

@@ -287,7 +287,7 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of,
 }
 
 void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
-		    struct rdtgroup *rdtgrp, int evtid)
+		    struct rdtgroup *rdtgrp, int evtid, int first)
 {
 	/*
 	 * setup the parameters to send to the IPI to read the data.
@@ -296,6 +296,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_domain *d,
 	rr->evtid = evtid;
 	rr->d = d;
 	rr->val = 0;
+	rr->first = first;
 
 	smp_call_function_any(&d->cpu_mask, mon_event_count, rr, 1);
 }
@@ -325,7 +326,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 		goto out;
 	}
 
-	mon_event_read(&rr, d, rdtgrp, evtid);
+	mon_event_read(&rr, d, rdtgrp, evtid, false);
 
 	if (rr.val & RMID_VAL_ERROR)
 		seq_puts(m, "Error\n");

arch/x86/kernel/cpu/intel_rdt_monitor.c

@@ -321,6 +321,13 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
 		 */
 		return -EINVAL;
 	}
+
+	if (rr->first) {
+		m->prev_msr = tval;
+		m->chunks = 0;
+		return 0;
+	}
+
 	shift = 64 - MBM_CNTR_WIDTH;
 	chunks = (tval << shift) - (m->prev_msr << shift);
 	chunks >>= shift;

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

@@ -1351,6 +1351,7 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
 	union mon_data_bits priv;
 	struct kernfs_node *kn;
 	struct mon_evt *mevt;
+	struct rmid_read rr;
 	char name[32];
 	int ret;
 
@@ -1381,6 +1382,9 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
 		ret = mon_addfile(kn, mevt->name, priv.priv);
 		if (ret)
 			goto out_destroy;
+
+		if (is_mbm_event(mevt->evtid))
+			mon_event_read(&rr, d, prgrp, mevt->evtid, true);
 	}
 	kernfs_activate(kn);
 	return 0;