[PATCH v8 11/21] fs/resctrl: Add boiler plate for external resctrl code

James Morse
2025-04-11T16:43:52Z

Add Makefile and Kconfig for fs/resctrl. Add ARCH_HAS_CPU_RESCTRL
for the common parts of the resctrl interface and make X86_CPU_RESCTRL
select this.

Adding an include of asm/resctrl.h to linux/resctrl.h allows the
/fs/resctrl files to switch over to using this header instead.

Co-developed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64
Tested-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
---
Changes since v6:
* Added 'depends on RESCTRL_FS' to the hidden kconfig options.

Changes since v5:
* Removed double include.
* Removed duplicate pseudo lock Kconfig define
* Grammar fix and closid capitalisation change.

Changes since v4:
* Tweaking of the commit message.

Changes since v3:
* Reworded 'if unsure say N' from the Kconfig text, the user doesn't have
the choice anyway at this point.
* Added PWD to monitor.o's CFLAGS for the ftrace rube-goldberg build machine.
* Added split trace files.

Changes since v2:
* Dropped KERNFS dependency from arch side Kconfig.
* Added empty trace.h file.
* Merged asm->linux includes from Dave's patch to decouple those
patches from this series.

Changes since v1:
* Rename new file psuedo_lock.c to pseudo_lock.c, to match the name
of the original file (and to be less surprising).

* [Whitespace only] Under RESCTRL_FS in fs/resctrl/Kconfig, delete
alignment space in orphaned select ... if (which has nothing to line
up with any more).

* [Whitespace only] Reflow and re-tab Kconfig additions.
---
MAINTAINERS | 1 +
arch/Kconfig | 8 +++++
arch/x86/Kconfig | 11 ++-----
arch/x86/kernel/cpu/resctrl/internal.h | 2 --
arch/x86/kernel/cpu/resctrl/monitor.c | 2 +-
arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 2 +-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 +-
fs/Kconfig | 1 +
fs/Makefile | 1 +
fs/resctrl/Kconfig | 39 +++++++++++++++++++++++
fs/resctrl/Makefile | 6 ++++
fs/resctrl/ctrlmondata.c | 0
fs/resctrl/internal.h | 0
fs/resctrl/monitor.c | 0
fs/resctrl/monitor_trace.h | 0
fs/resctrl/pseudo_lock.c | 0
fs/resctrl/pseudo_lock_trace.h | 0
fs/resctrl/rdtgroup.c | 0
include/linux/resctrl.h | 4 +++
19 files changed, 66 insertions(+), 13 deletions(-)
create mode 100644 fs/resctrl/Kconfig
create mode 100644 fs/resctrl/Makefile
create mode 100644 fs/resctrl/ctrlmondata.c
create mode 100644 fs/resctrl/internal.h
create mode 100644 fs/resctrl/monitor.c
create mode 100644 fs/resctrl/monitor_trace.h
create mode 100644 fs/resctrl/pseudo_lock.c
create mode 100644 fs/resctrl/pseudo_lock_trace.h
create mode 100644 fs/resctrl/rdtgroup.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 96b827049501..c30c6fbd1f7a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20284,6 +20284,7 @@ S: Supported
F: Documentation/arch/x86/resctrl*
F: arch/x86/include/asm/resctrl.h
F: arch/x86/kernel/cpu/resctrl/
+F: fs/resctrl/
F: include/linux/resctrl*.h
F: tools/testing/selftests/resctrl/

diff --git a/arch/Kconfig b/arch/Kconfig
index b0adb665041f..a3308a220f86 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1518,6 +1518,14 @@ config STRICT_MODULE_RWX
config ARCH_HAS_PHYS_TO_DMA
bool

+config ARCH_HAS_CPU_RESCTRL
+ bool
+ help
+ An architecture selects this option to indicate that the necessary
+ hooks are provided to support the common memory system usage
+ monitoring and control interfaces provided by the 'resctrl'
+ filesystem (see RESCTRL_FS).
+
config HAVE_ARCH_COMPILER_H
bool
help
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4b9f378e05f6..5a09acf41c8e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -507,8 +507,9 @@ config X86_MPPARSE
config X86_CPU_RESCTRL
bool "x86 CPU resource control support"
depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
- select KERNFS
- select PROC_CPU_RESCTRL if PROC_FS
+ depends on MISC_FILESYSTEMS
+ select ARCH_HAS_CPU_RESCTRL
+ select RESCTRL_FS
select RESCTRL_FS_PSEUDO_LOCK
help
Enable x86 CPU resource control support.
@@ -526,12 +527,6 @@ config X86_CPU_RESCTRL

Say N if unsure.

-config RESCTRL_FS_PSEUDO_LOCK
- bool
- help
- Software mechanism to pin data in a cache portion using
- micro-architecture specific knowledge.
-
config X86_FRED
bool "Flexible Return and Event Delivery"
depends on X86_64
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index d932dd1eaa74..365d5697a6ae 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -9,8 +9,6 @@
#include <linux/jump_label.h>
#include <linux/tick.h>

-#include <asm/resctrl.h>
-
#define L3_QOS_CDP_ENABLE 0x01ULL

#define L2_QOS_CDP_ENABLE 0x01ULL
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 99de915a6f69..a9e1116f5ccc 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -19,11 +19,11 @@

#include <linux/cpu.h>
#include <linux/module.h>
+#include <linux/resctrl.h>
#include <linux/sizes.h>
#include <linux/slab.h>

#include <asm/cpu_device_id.h>
-#include <asm/resctrl.h>

#include "internal.h"

diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index f7bb586a83f9..db0b75b45fe4 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -18,12 +18,12 @@
#include <linux/mman.h>
#include <linux/perf_event.h>
#include <linux/pm_qos.h>
+#include <linux/resctrl.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

#include <asm/cacheflush.h>
#include <asm/cpu_device_id.h>
-#include <asm/resctrl.h>
#include <asm/perf_event.h>

#include "../../events/perf_event.h" /* For X86_CONFIG() */
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index d61b7137f443..23fd92cc0c56 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -18,6 +18,7 @@
#include <linux/fs_parser.h>
#include <linux/sysfs.h>
#include <linux/kernfs.h>
+#include <linux/resctrl.h>
#include <linux/seq_buf.h>
#include <linux/seq_file.h>
#include <linux/sched/signal.h>
@@ -28,7 +29,6 @@

#include <uapi/linux/magic.h>

-#include <asm/resctrl.h>
#include "internal.h"

DEFINE_STATIC_KEY_FALSE(rdt_enable_key);
diff --git a/fs/Kconfig b/fs/Kconfig
index c718b2e2de0e..53c9273e34b9 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -335,6 +335,7 @@ source "fs/omfs/Kconfig"
source "fs/hpfs/Kconfig"
source "fs/qnx4/Kconfig"
source "fs/qnx6/Kconfig"
+source "fs/resctrl/Kconfig"
source "fs/romfs/Kconfig"
source "fs/pstore/Kconfig"
source "fs/ufs/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index 77fd7f7b5d02..79c08b914c47 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -128,3 +128,4 @@ obj-$(CONFIG_EROFS_FS) += erofs/
obj-$(CONFIG_VBOXSF_FS) += vboxsf/
obj-$(CONFIG_ZONEFS_FS) += zonefs/
obj-$(CONFIG_BPF_LSM) += bpf_fs_kfuncs.o
+obj-$(CONFIG_RESCTRL_FS) += resctrl/
diff --git a/fs/resctrl/Kconfig b/fs/resctrl/Kconfig
new file mode 100644
index 000000000000..478a8e2ad99f
--- /dev/null
+++ b/fs/resctrl/Kconfig
@@ -0,0 +1,39 @@
+config RESCTRL_FS
+ bool "CPU Resource Control Filesystem (resctrl)"
+ depends on ARCH_HAS_CPU_RESCTRL
+ select KERNFS
+ select PROC_CPU_RESCTRL if PROC_FS
+ help
+ Some architectures provide hardware facilities to group tasks and
+ monitor and control their usage of memory system resources such as
+ caches and memory bandwidth. Examples of such facilities include
+ Intel's Resource Director Technology (Intel(R) RDT) and AMD's
+ Platform Quality of Service (AMD QoS).
+
+ If your system has the necessary support and you want to be able to
+ assign tasks to groups and manipulate the associated resource
+ monitors and controls from userspace, say Y here to get a mountable
+ 'resctrl' filesystem that lets you do just that.
+
+ If nothing mounts or prods the 'resctrl' filesystem, resource
+ controls and monitors are left in a quiescent, permissive state.
+
+ On architectures where this can be disabled independently, it is
+ safe to say N.
+
+ See <file:Documentation/arch/x86/resctrl.rst> for more information.
+
+config RESCTRL_FS_PSEUDO_LOCK
+ bool
+ depends on RESCTRL_FS
+ help
+ Software mechanism to pin data in a cache portion using
+ micro-architecture specific knowledge.
+
+config RESCTRL_RMID_DEPENDS_ON_CLOSID
+ bool
+ depends on RESCTRL_FS
+ help
+ Enabled by the architecture when the RMID values depend on the CLOSID.
+ This causes the CLOSID allocator to search for CLOSID with clean
+ RMID.
diff --git a/fs/resctrl/Makefile b/fs/resctrl/Makefile
new file mode 100644
index 000000000000..e67f34d2236a
--- /dev/null
+++ b/fs/resctrl/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_RESCTRL_FS) += rdtgroup.o ctrlmondata.o monitor.o
+obj-$(CONFIG_RESCTRL_FS_PSEUDO_LOCK) += pseudo_lock.o
+
+# To allow define_trace.h's recursive include:
+CFLAGS_monitor.o = -I$(src)
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/monitor_trace.h b/fs/resctrl/monitor_trace.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/pseudo_lock_trace.h b/fs/resctrl/pseudo_lock_trace.h
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index b8f8240050b4..5c7c8bf2c47f 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -8,6 +8,10 @@
#include <linux/pid.h>
#include <linux/resctrl_types.h>

+#ifdef CONFIG_ARCH_HAS_CPU_RESCTRL
+#include <asm/resctrl.h>
+#endif
+
/* CLOSID, RMID value used by the default control group */
#define RESCTRL_RESERVED_CLOSID 0
#define RESCTRL_RESERVED_RMID 0
--
2.20.1