[PATCH v3 11/26] fs/resctrl: Add support for additional monitor event display formats

[Tony Luck <tony.luck@intel.com>]

Add a type field to both the mon_evt and mon_data structures.

Legacy monitor events are still all displayed as an unsigned decimal
64-bit integer.

Add an additional format of fixed-point with 18 binary places displayed
as a floating point value with six decimal places.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 include/linux/resctrl_types.h |  8 ++++++++
 fs/resctrl/internal.h         |  4 ++++
 fs/resctrl/ctrlmondata.c      | 23 ++++++++++++++++++++++-
 fs/resctrl/monitor.c          |  3 +++
 fs/resctrl/rdtgroup.c         |  1 +
 5 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/include/linux/resctrl_types.h b/include/linux/resctrl_types.h
index 898068a99ef7..fbd4b55c41aa 100644
--- a/include/linux/resctrl_types.h
+++ b/include/linux/resctrl_types.h
@@ -58,6 +58,14 @@ enum resctrl_event_id {
 #define QOS_NUM_MBM_EVENTS	(QOS_L3_MBM_LOCAL_EVENT_ID - QOS_L3_MBM_TOTAL_EVENT_ID + 1)
 #define MBM_EVENT_IDX(evt)	((evt) - QOS_L3_MBM_TOTAL_EVENT_ID)
 
+/*
+ * Event value display types
+ */
+enum resctrl_event_type {
+	EVT_TYPE_U64,
+	EVT_TYPE_U46_18,
+};
+
 static inline bool resctrl_is_mbm_event(int e)
 {
 	return (e >= QOS_L3_MBM_TOTAL_EVENT_ID &&
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 74a77794364d..4a840e683e96 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -71,6 +71,7 @@ static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
  * struct mon_evt - Entry in the event list of a resource
  * @evtid:		event id
  * @name:		name of the event
+ * @type:		format for display to user
  * @configurable:	true if the event is configurable
  * @any_cpu:		true if this event can be read from any CPU
  * @list:		entry in &rdt_resource->evt_list
@@ -79,6 +80,7 @@ struct mon_evt {
 	enum resctrl_event_id	evtid;
 	enum resctrl_res_level	rid;
 	char			*name;
+	enum resctrl_event_type	type;
 	bool			configurable;
 	bool			any_cpu;
 	struct list_head	list;
@@ -89,6 +91,7 @@ struct mon_evt {
  * @list:            List of all allocated structures.
  * @rid:             Resource id associated with the event file.
  * @evtid:           Event id associated with the event file.
+ * @type:            Format for display to user
  * @sum:             Set when event must be summed across multiple
  *                   domains.
  * @domid:           When @sum is zero this is the domain to which
@@ -104,6 +107,7 @@ struct mon_data {
 	struct list_head list;
 	unsigned int rid;
 	enum resctrl_event_id evtid;
+	enum resctrl_event_type type;
 	unsigned int sum;
 	unsigned int domid;
 	bool any_cpu;
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index cd77960657f0..5ea8113c96ac 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -562,6 +562,27 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
 	resctrl_arch_mon_ctx_free(r, evtid, rr->arch_mon_ctx);
 }
 
+#define NUM_FRAC_BITS	18
+#define FRAC_MASK	GENMASK(NUM_FRAC_BITS - 1, 0)
+
+static void show_value(struct seq_file *m, enum resctrl_event_type type, u64 val)
+{
+	u64 frac;
+
+	switch (type) {
+	case EVT_TYPE_U64:
+		seq_printf(m, "%llu\n", val);
+		break;
+	case EVT_TYPE_U46_18:
+		frac = val & FRAC_MASK;
+		frac = frac * 1000000;
+		frac += 1ul << (NUM_FRAC_BITS - 1);
+		frac >>= NUM_FRAC_BITS;
+		seq_printf(m, "%llu.%06llu\n", val >> NUM_FRAC_BITS, frac);
+		break;
+	}
+}
+
 int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 {
 	struct kernfs_open_file *of = m->private;
@@ -633,7 +654,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
 	else if (rr.err == -EINVAL)
 		seq_puts(m, "Unavailable\n");
 	else
-		seq_printf(m, "%llu\n", rr.val);
+		show_value(m, md->type, rr.val);
 
 out:
 	rdtgroup_kn_unlock(of->kn);
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 1cf0b085e07a..1efad57d1d85 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -847,16 +847,19 @@ static struct mon_evt all_events[QOS_NUM_EVENTS] = {
 		.name	= "llc_occupancy",
 		.evtid	= QOS_L3_OCCUP_EVENT_ID,
 		.rid	= RDT_RESOURCE_L3,
+		.type	= EVT_TYPE_U64,
 	},
 	[QOS_L3_MBM_TOTAL_EVENT_ID] = {
 		.name	= "mbm_total_bytes",
 		.evtid	= QOS_L3_MBM_TOTAL_EVENT_ID,
 		.rid	= RDT_RESOURCE_L3,
+		.type	= EVT_TYPE_U64,
 	},
 	[QOS_L3_MBM_LOCAL_EVENT_ID] = {
 		.name	= "mbm_local_bytes",
 		.evtid	= QOS_L3_MBM_LOCAL_EVENT_ID,
 		.rid	= RDT_RESOURCE_L3,
+		.type	= EVT_TYPE_U64,
 	},
 };
 
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 97c2ba8af930..bd41f7a0f416 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -2927,6 +2927,7 @@ static struct mon_data *mon_get_kn_priv(int rid, int domid, struct mon_evt *mevt
 	priv->sum = do_sum;
 	priv->evtid = mevt->evtid;
 	priv->any_cpu = mevt->any_cpu;
+	priv->type = mevt->type;
 	list_add_tail(&priv->list, &kn_priv_list);
 
 	return priv;
-- 
2.48.1