linux-kernel - [PATCH 08/15] x86/resctrl: Introduce interface to display number of ABMC counters

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Message-ID: <20231201005720.235639-9-babu.moger@amd.com>
Date:   Thu, 30 Nov 2023 18:57:13 -0600
From:   Babu Moger <babu.moger@....com>
To:     <corbet@....net>, <fenghua.yu@...el.com>,
        <reinette.chatre@...el.com>, <tglx@...utronix.de>,
        <mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>
CC:     <x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
        <rdunlap@...radead.org>, <tj@...nel.org>, <peterz@...radead.org>,
        <seanjc@...gle.com>, <kim.phillips@....com>, <babu.moger@....com>,
        <jmattson@...gle.com>, <ilpo.jarvinen@...ux.intel.com>,
        <jithu.joseph@...el.com>, <kan.liang@...ux.intel.com>,
        <nikunj@....com>, <daniel.sneddon@...ux.intel.com>,
        <pbonzini@...hat.com>, <rick.p.edgecombe@...el.com>,
        <rppt@...nel.org>, <maciej.wieczor-retman@...el.com>,
        <linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <eranian@...gle.com>, <peternewman@...gle.com>, <dhagiani@....com>
Subject: [PATCH 08/15] x86/resctrl: Introduce interface to display number of ABMC counters

The ABMC feature provides an option to the user to pin (or assign) the
RMID to the hardware counter and monitor the bandwidth for a longer
duration. There are only a limited number of hardware counters.

Provide the interface to display the number of ABMC counters supported.

Signed-off-by: Babu Moger <babu.moger@....com>
---
 Documentation/arch/x86/resctrl.rst     |  4 ++++
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 29 +++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 19e906f629d4..87aa8eec71b7 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -266,6 +266,10 @@ with the following files:
 	    # cat /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config
 	    0=0x30;1=0x30;3=0x15;4=0x15
 
+"abmc_counters":
+	Available when ABMC feature is enabled. The number of ABMC counters
+	available for assignment.
+
 "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/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 7f6ed903ba17..897707694cc8 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -811,6 +811,17 @@ static int rdtgroup_rmid_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+static int rdtgroup_abmc_counters_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);
+
+	seq_printf(s, "%d\n", hw_res->abmc_counters);
+
+	return 0;
+}
+
 #ifdef CONFIG_PROC_CPU_RESCTRL
 
 /*
@@ -1861,6 +1872,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= mbm_local_bytes_config_show,
 		.write		= mbm_local_bytes_config_write,
 	},
+	{
+		.name		= "abmc_counters",
+		.mode		= 0444,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= rdtgroup_abmc_counters_show,
+	},
 	{
 		.name		= "cpus",
 		.mode		= 0644,
@@ -2419,12 +2436,22 @@ static void resctrl_abmc_disable(enum resctrl_res_level l)
 int resctrl_arch_set_abmc_enabled(enum resctrl_res_level l, bool enable)
 {
 	struct rdt_hw_resource *hw_res = &rdt_resources_all[l];
+	struct rftype *rft;
 
 	if (!hw_res->r_resctrl.abmc_capable)
 		return -EINVAL;
 
-	if (enable)
+	if (enable) {
+		rft = rdtgroup_get_rftype_by_name("abmc_counters");
+		if (rft)
+			rft->fflags = RFTYPE_MON_INFO;
+
 		return resctrl_abmc_enable(l);
+	}
+
+	rft = rdtgroup_get_rftype_by_name("abmc_counters");
+	if (rft)
+		rft->fflags &= ~RFTYPE_MON_INFO;
 
 	resctrl_abmc_disable(l);
 
-- 
2.34.1