[RFC PATCH v3 05/17] x86/resctrl: Introduce the interface to display the assignment state

Babu Moger
2024-03-29T01:07:44Z

The ABMC feature provides an option to the user to assign an RMID
to the hardware counter and monitor the bandwidth for a longer duration.
System can be in only one mode at a time (Legacy Monitor mode or ABMC
mode). By default, ABMC mode is disabled.

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

When the feature is enabled
$cat /sys/fs/resctrl/info/L3_MON/mbm_assign
[abmc]

Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v3: New patch to display ABMC capability.
---
Documentation/arch/x86/resctrl.rst | 5 +++++
arch/x86/kernel/cpu/resctrl/monitor.c | 4 +++-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 17 +++++++++++++++++
3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 68df7751d1f5..cd973a013525 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -257,6 +257,11 @@ with the following files:
# cat /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config
0=0x30;1=0x30;3=0x15;4=0x15

+"mbm_assign":
+ Available when assignable monitoring features are supported.
+ Reports the list of assignable features supported and the enclosed brackets
+ indicate the feature is enabled.
+
"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 735b449039c1..48d1957ea5a3 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1058,8 +1058,10 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
RFTYPE_MON_INFO | RFTYPE_RES_CACHE);
}

- if (resctrl_arch_has_abmc(r))
+ if (resctrl_arch_has_abmc(r)) {
r->mbm_assign_capable = ABMC_ASSIGN;
+ resctrl_file_fflags_init("mbm_assign", RFTYPE_MON_INFO);
+ }
}

l3_mon_evt_init(r);
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index dda71fb6c10e..5ec807e8dd38 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -846,6 +846,17 @@ static int rdtgroup_rmid_show(struct kernfs_open_file *of,
return ret;
}

+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;
+
+ if (r->mbm_assign_capable)
+ seq_puts(s, "abmc\n");
+
+ return 0;
+}
+
#ifdef CONFIG_PROC_CPU_RESCTRL

/*
@@ -1903,6 +1914,12 @@ 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