[PATCH v9 14/26] x86/resctrl: Introduce interface to display number of free counters

[Babu Moger]

Provide the interface to display the number of free monitoring counters
available for assignment in each doamin when mbm_cntr_assign is supported.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v9: New patch.
---
 Documentation/arch/x86/resctrl.rst     |  4 ++++
 arch/x86/kernel/cpu/resctrl/monitor.c  |  1 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 33 ++++++++++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 2f3a86278e84..2bc58d974934 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -302,6 +302,10 @@ with the following files:
 	memory bandwidth tracking to a single memory bandwidth event per
 	monitoring group.
 
+"available_mbm_cntrs":
+	The number of free monitoring counters available assignment in each domain
+	when the architecture supports mbm_cntr_assign mode.
+
 "max_threshold_occupancy":
 		Read/write file provides the largest value (in
 		bytes) at which a previously used LLC_occupancy
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 3996f7528b66..e8d38a963f39 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1268,6 +1268,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
 			cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
 			r->mon.num_mbm_cntrs = (ebx & GENMASK(15, 0)) + 1;
 			resctrl_file_fflags_init("num_mbm_cntrs", RFTYPE_MON_INFO);
+			resctrl_file_fflags_init("available_mbm_cntrs", RFTYPE_MON_INFO);
 		}
 	}
 
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 654cdfee1b00..ef0c1246fa2a 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -898,6 +898,33 @@ static int rdtgroup_num_mbm_cntrs_show(struct kernfs_open_file *of,
 	return 0;
 }
 
+static int rdtgroup_available_mbm_cntrs_show(struct kernfs_open_file *of,
+					     struct seq_file *s, void *v)
+{
+	struct rdt_resource *r = of->kn->parent->priv;
+	struct rdt_mon_domain *dom;
+	bool sep = false;
+	u32 val;
+
+	cpus_read_lock();
+	mutex_lock(&rdtgroup_mutex);
+
+	list_for_each_entry(dom, &r->mon_domains, hdr.list) {
+		if (sep)
+			seq_puts(s, ";");
+
+		val = r->mon.num_mbm_cntrs - hweight64(*dom->mbm_cntr_map);
+		seq_printf(s, "%d=%d", dom->hdr.id, val);
+		sep = true;
+	}
+	seq_puts(s, "\n");
+
+	mutex_unlock(&rdtgroup_mutex);
+	cpus_read_unlock();
+
+	return 0;
+}
+
 #ifdef CONFIG_PROC_CPU_RESCTRL
 
 /*
@@ -1984,6 +2011,12 @@ static struct rftype res_common_files[] = {
 		.kf_ops		= &rdtgroup_kf_single_ops,
 		.seq_show	= rdtgroup_num_mbm_cntrs_show,
 	},
+	{
+		.name		= "available_mbm_cntrs",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_available_mbm_cntrs_show,
+	},
 	{
 		.name		= "cpus_list",
 		.mode		= 0644,
-- 
2.34.1