[PATCH v4 08/19] x86/resctrl: Introduce the interface to display monitor mode

Babu Moger
2024-05-24T12:25:02Z

The ABMC feature provides an option to the user to assign a hardware
counter to an RMID and monitor the bandwidth as long as it is assigned.
ABMC mode is enabled by default when supported. System can be one mode
at a time (Legacy monitor mode or ABMC mode).

Provide an interface to display the monitor mode on the system.
$cat /sys/fs/resctrl/info/L3_MON/mbm_assign
[abmc]
legacy

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v4: Fixed the checks for legacy and abmc mode. Default it ABMC.

v3: New patch to display ABMC capability.
---
Documentation/arch/x86/resctrl.rst | 10 ++++++++++
arch/x86/kernel/cpu/resctrl/monitor.c | 1 +
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 23 +++++++++++++++++++++++
3 files changed, 34 insertions(+)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 7ab8172ef208..ab3cde61a124 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -261,6 +261,16 @@ with the following files:
Available when ABMC feature is supported. The number of ABMC counters
available for configuration.

+"mbm_assign":
+ Available when ABMC feature is supported. Reports the list of assignable
+ monitoring features supported. The enclosed brackets indicate which
+ feature is enabled.
+ ::
+
+ cat /sys/fs/resctrl/info/L3_MON/mbm_assign
+ [abmc]
+ mbm_legacy
+
"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 e75a6146068b..b1d002e5e93d 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1071,6 +1071,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)

if (rdt_cpu_has(X86_FEATURE_ABMC)) {
r->abmc_capable = true;
+ resctrl_file_fflags_init("mbm_assign", RFTYPE_MON_INFO);
/*
* Query CPUID_Fn80000020_EBX_x05 for number of
* ABMC counters
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 9148d1234ede..3071bbb7a15e 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -856,6 +856,23 @@ static int rdtgroup_num_cntrs_show(struct kernfs_open_file *of,
return 0;
}

+static int rdtgroup_mbm_assign_show(struct kernfs_open_file *of,
+ struct seq_file *s, void *v)
+{
+ struct rdt_resource *r = of->kn->parent->priv;
+ struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
+
+ if (hw_res->abmc_enabled) {
+ seq_puts(s, "[abmc]\n");
+ seq_puts(s, "mbm_legacy\n");
+ } else {
+ seq_puts(s, "abmc\n");
+ seq_puts(s, "[mbm_legacy]\n");
+ }
+
+ return 0;
+}
+
#ifdef CONFIG_PROC_CPU_RESCTRL

/*
@@ -1913,6 +1930,12 @@ static struct rftype res_common_files[] = {
.seq_show = mbm_local_bytes_config_show,
.write = mbm_local_bytes_config_write,
},
+ {
+ .name = "mbm_assign",
+ .mode = 0444,
+ .kf_ops = &rdtgroup_kf_single_ops,
+ .seq_show = rdtgroup_mbm_assign_show,
+ },
{
.name = "cpus",
.mode = 0644,
--
2.34.1