[PATCH 10/21] x86/intel_rdt/cqm: Add info files for RDT monitoring

[Vikas Shivappa]

Add info directory files specific to RDT monitoring.

 num_rmids:
    The number of RMIDs which are valid for the resource.

 mon_features:
    Lists the monitoring events if monitoring is enabled for the
    resource.

 max_threshold_occupancy:
    This is specific to llc_occupancy monitoring and is used to
    determine if an RMID can be reused. Provides an upper bound on the
    threshold and is shown to the user in bytes though the internal
    value will be rounded to the scaling factor supported by the h/w.

Signed-off-by: Vikas Shivappa <vikas.shivappa@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/intel_rdt.h          |   8 ++
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 121 +++++++++++++++++++++++++++----
 2 files changed, 113 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index eb41b21..c0acfc3 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -68,11 +68,14 @@ struct rdtgroup {
 #define RFTYPE_INFO			1U
 #define RFTYPE_BASE			(1U << 1)
 #define RF_CTRLSHIFT			4
+#define RF_MONSHIFT			5
 #define RFTYPE_CTRL			(1U << RF_CTRLSHIFT)
+#define RFTYPE_MON			(1U << RF_MONSHIFT)
 #define RFTYPE_RES_CACHE		(1U << 8)
 #define RFTYPE_RES_MB			(1U << 9)
 
 #define RF_CTRL_INFO		(RFTYPE_INFO | RFTYPE_CTRL)
+#define RF_MON_INFO		(RFTYPE_INFO | RFTYPE_MON)
 #define RF_CTRL_BASE		(RFTYPE_BASE | RFTYPE_CTRL)
 
 /* List of all resource groups */
@@ -257,6 +260,11 @@ enum {
 	     r++)							      \
 		if (r->alloc_enabled)
 
+#define for_each_mon_enabled_rdt_resource(r)				      \
+	for (r = rdt_resources_all; r < rdt_resources_all + RDT_NUM_RESOURCES;\
+	     r++)							      \
+		if (r->mon_enabled)
+
 /* CPUID.(EAX=10H, ECX=ResID=1).EAX */
 union cpuid_0x10_1_eax {
 	struct {
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 1c53802..e997330 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -490,6 +490,28 @@ static int rdt_min_bw_show(struct kernfs_open_file *of,
 	return 0;
 }
 
+static int rdt_num_rmids_show(struct kernfs_open_file *of,
+			      struct seq_file *seq, void *v)
+{
+	struct rdt_resource *r = of->kn->parent->priv;
+
+	seq_printf(seq, "%d\n", r->num_rmid);
+
+	return 0;
+}
+
+static int rdt_mon_features_show(struct kernfs_open_file *of,
+				 struct seq_file *seq, void *v)
+{
+	struct rdt_resource *r = of->kn->parent->priv;
+	struct mon_evt *mevt;
+
+	list_for_each_entry(mevt, &r->evt_list, list)
+		seq_printf(seq, "%s\n", mevt->name);
+
+	return 0;
+}
+
 static int rdt_bw_gran_show(struct kernfs_open_file *of,
 			     struct seq_file *seq, void *v)
 {
@@ -508,6 +530,35 @@ static int rdt_delay_linear_show(struct kernfs_open_file *of,
 	return 0;
 }
 
+static int max_threshold_occ_show(struct kernfs_open_file *of,
+				  struct seq_file *seq, void *v)
+{
+	struct rdt_resource *r = of->kn->parent->priv;
+
+	seq_printf(seq, "%u\n", intel_cqm_threshold * r->mon_scale);
+
+	return 0;
+}
+
+static ssize_t max_threshold_occ_write(struct kernfs_open_file *of,
+				       char *buf, size_t nbytes, loff_t off)
+{
+	struct rdt_resource *r = of->kn->parent->priv;
+	unsigned int bytes;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &bytes);
+	if (ret)
+		return ret;
+
+	if (bytes > (boot_cpu_data.x86_cache_size * 1024))
+		return -EINVAL;
+
+	intel_cqm_threshold = bytes / r->mon_scale;
+
+	return ret ?: nbytes;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_common_files[] = {
 	{
@@ -518,6 +569,20 @@ static int rdt_delay_linear_show(struct kernfs_open_file *of,
 		.fflags		= RF_CTRL_INFO,
 	},
 	{
+		.name		= "mon_features",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdt_mon_features_show,
+		.fflags		= RF_MON_INFO,
+	},
+	{
+		.name		= "num_rmids",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdt_num_rmids_show,
+		.fflags		= RF_MON_INFO,
+	},
+	{
 		.name		= "cbm_mask",
 		.mode		= 0444,
 		.kf_ops		= &rdtgroup_kf_single_ops,
@@ -553,6 +618,14 @@ static int rdt_delay_linear_show(struct kernfs_open_file *of,
 		.fflags		= RF_CTRL_INFO | RFTYPE_RES_MB,
 	},
 	{
+		.name		= "max_threshold_occupancy",
+		.mode		= 0644,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.write		= max_threshold_occ_write,
+		.seq_show	= max_threshold_occ_show,
+		.fflags		= RF_MON_INFO | RFTYPE_RES_CACHE,
+	},
+	{
 		.name		= "cpus",
 		.mode		= 0644,
 		.kf_ops		= &rdtgroup_kf_single_ops,
@@ -615,15 +688,37 @@ static int rdtgroup_add_files(struct kernfs_node *kn, unsigned long fflags)
 	return ret;
 }
 
-static u32 getres_fflags(struct rdt_resource *r)
+static int rdtgroup_mkdir_info_resdir(struct rdt_resource *r, char *name,
+				      unsigned long fflags)
 {
-	return (r->fflags | (r->alloc_enabled << RF_CTRLSHIFT));
+	struct kernfs_node *kn_subdir;
+	int ret;
+
+	kn_subdir = kernfs_create_dir(kn_info, name,
+				      kn_info->mode, r);
+	if (IS_ERR(kn_subdir)) {
+		ret = PTR_ERR(kn_subdir);
+		goto out_fail;
+	}
+	kernfs_get(kn_subdir);
+	ret = rdtgroup_kn_set_ugid(kn_subdir);
+	if (ret)
+		goto out_fail;
+
+	ret = rdtgroup_add_files(kn_subdir, fflags);
+	if (ret)
+		goto out_fail;
+	kernfs_activate(kn_subdir);
+
+out_fail:
+	return ret;
 }
 
 static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 {
-	struct kernfs_node *kn_subdir;
 	struct rdt_resource *r;
+	unsigned long fflags;
+	char name[32];
 	int ret;
 
 	/* create the directory */
@@ -633,22 +728,16 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 	kernfs_get(kn_info);
 
 	for_each_alloc_enabled_rdt_resource(r) {
-		kn_subdir = kernfs_create_dir(kn_info, r->name,
-					      kn_info->mode, r);
-		if (IS_ERR(kn_subdir)) {
-			ret = PTR_ERR(kn_subdir);
-			goto out_destroy;
-		}
-		kernfs_get(kn_subdir);
-		ret = rdtgroup_kn_set_ugid(kn_subdir);
-		if (ret)
+		fflags =  r->fflags | RF_CTRL_INFO;
+		if (rdtgroup_mkdir_info_resdir(r, r->name, fflags))
 			goto out_destroy;
+	}
 
-		ret = rdtgroup_add_files(kn_subdir, getres_fflags(r) |
-					 RFTYPE_INFO);
-		if (ret)
+	for_each_mon_enabled_rdt_resource(r) {
+		fflags =  r->fflags | RF_MON_INFO;
+		sprintf(name, "%s_MON", r->name);
+		if (rdtgroup_mkdir_info_resdir(r, name, fflags))
 			goto out_destroy;
-		kernfs_activate(kn_subdir);
 	}
 
 	/*
-- 
1.9.1