linux-kernel - [tip: x86/cache] x86,fs/resctrl: Add and initialize a resource for package scope monitoring

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Message-ID: <176807436733.510.16512267630246746893.tip-bot2@tip-bot2>
Date: Sat, 10 Jan 2026 19:46:07 -0000
From: "tip-bot2 for Tony Luck" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Tony Luck <tony.luck@...el.com>, "Borislav Petkov (AMD)" <bp@...en8.de>,
 Reinette Chatre <reinette.chatre@...el.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/cache] x86,fs/resctrl: Add and initialize a resource for
 package scope monitoring

The following commit has been merged into the x86/cache branch of tip:

Commit-ID:     2e53ad66686a46b141c3395719afeee3057ffe2f
Gitweb:        https://git.kernel.org/tip/2e53ad66686a46b141c3395719afeee3057ffe2f
Author:        Tony Luck <tony.luck@...el.com>
AuthorDate:    Wed, 17 Dec 2025 09:21:01 -08:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Fri, 09 Jan 2026 16:37:07 +01:00

x86,fs/resctrl: Add and initialize a resource for package scope monitoring

Add a new PERF_PKG resource and introduce package level scope for monitoring
telemetry events so that CPU hotplug notifiers can build domains at the
package granularity.

Use the physical package ID available via topology_physical_package_id()
to identify the monitoring domains with package level scope. This enables
user space to use:

  /sys/devices/system/cpu/cpuX/topology/physical_package_id

to identify the monitoring domain a CPU is associated with.

Signed-off-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
---
 arch/x86/kernel/cpu/resctrl/core.c | 10 ++++++++++
 fs/resctrl/internal.h              |  2 ++
 fs/resctrl/rdtgroup.c              |  2 ++
 include/linux/resctrl.h            |  2 ++
 4 files changed, 16 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index a2b7f86..f3d7e22 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -100,6 +100,14 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 			.schema_fmt		= RESCTRL_SCHEMA_RANGE,
 		},
 	},
+	[RDT_RESOURCE_PERF_PKG] =
+	{
+		.r_resctrl = {
+			.name			= "PERF_PKG",
+			.mon_scope		= RESCTRL_PACKAGE,
+			.mon_domains		= mon_domain_init(RDT_RESOURCE_PERF_PKG),
+		},
+	},
 };
 
 u32 resctrl_arch_system_num_rmid_idx(void)
@@ -440,6 +448,8 @@ static int get_domain_id_from_scope(int cpu, enum resctrl_scope scope)
 		return get_cpu_cacheinfo_id(cpu, scope);
 	case RESCTRL_L3_NODE:
 		return cpu_to_node(cpu);
+	case RESCTRL_PACKAGE:
+		return topology_physical_package_id(cpu);
 	default:
 		break;
 	}
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 14e5a9e..0110d11 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -255,6 +255,8 @@ struct rdtgroup {
 
 #define RFTYPE_ASSIGN_CONFIG		BIT(11)
 
+#define RFTYPE_RES_PERF_PKG		BIT(12)
+
 #define RFTYPE_CTRL_INFO		(RFTYPE_INFO | RFTYPE_CTRL)
 
 #define RFTYPE_MON_INFO			(RFTYPE_INFO | RFTYPE_MON)
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 0e3b8bc..a06cefd 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -2396,6 +2396,8 @@ static unsigned long fflags_from_resource(struct rdt_resource *r)
 	case RDT_RESOURCE_MBA:
 	case RDT_RESOURCE_SMBA:
 		return RFTYPE_RES_MB;
+	case RDT_RESOURCE_PERF_PKG:
+		return RFTYPE_RES_PERF_PKG;
 	}
 
 	return WARN_ON_ONCE(1);
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 2f938a5..861e63e 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -53,6 +53,7 @@ enum resctrl_res_level {
 	RDT_RESOURCE_L2,
 	RDT_RESOURCE_MBA,
 	RDT_RESOURCE_SMBA,
+	RDT_RESOURCE_PERF_PKG,
 
 	/* Must be the last */
 	RDT_NUM_RESOURCES,
@@ -270,6 +271,7 @@ enum resctrl_scope {
 	RESCTRL_L2_CACHE = 2,
 	RESCTRL_L3_CACHE = 3,
 	RESCTRL_L3_NODE,
+	RESCTRL_PACKAGE,
 };
 
 /**