[PATCH v2 29/35] fs/resctrl: Add boiler plate for external resctrl code

From: Dave Martin
Date: Fri Apr 26 2024 - 11:16:13 EST

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From: James Morse <james.morse@xxxxxxx>

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
depend on this.

Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>

---

FYI: Dave Martin, James Morse (et al.):

* Review the new Kconfig RESCTRL_FS help text.

* Because RESCTRL_FS combines a userspace interface and a kernel
library providing services to its own backends, there is a circular
dependency between this option and the arch-specific options
(CONFIG_X86_RESCTRL and eventually CONFIG_ARM64_MPAM) that
nastifies the presentation of these options in Kconfig.

Can this be improved?

The current situation works, but is not very user-friendly for
menuconfig users.

Changes in v2:

* 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 | 10 +++-------
fs/Kconfig | 1 +
fs/Makefile | 1 +
fs/resctrl/Kconfig | 36 ++++++++++++++++++++++++++++++++++++
fs/resctrl/Makefile | 3 +++
fs/resctrl/ctrlmondata.c | 0
fs/resctrl/internal.h | 0
fs/resctrl/monitor.c | 0
fs/resctrl/pseudo_lock.c | 0
fs/resctrl/rdtgroup.c | 0
include/linux/resctrl.h | 4 ++++
13 files changed, 57 insertions(+), 7 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/pseudo_lock.c
create mode 100644 fs/resctrl/rdtgroup.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 5621dd823e79..c49090e9c777 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18543,6 +18543,7 @@ 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 fd18b7db2c77..f163964e6915 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1406,6 +1406,14 @@ 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 e071e564452e..cb043543f088 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -479,8 +479,10 @@ config GOLDFISH
config X86_CPU_RESCTRL
bool "x86 CPU resource control support"
depends on X86 && (CPU_SUP_INTEL || CPU_SUP_AMD)
+ depends on MISC_FILESYSTEMS
select KERNFS
- select PROC_CPU_RESCTRL if PROC_FS
+ select ARCH_HAS_CPU_RESCTRL
+ select RESCTRL_FS
select RESCTRL_FS_PSEUDO_LOCK
help
Enable x86 CPU resource control support.
@@ -507,12 +509,6 @@ config X86_FRED
ring transitions and exception/interrupt handling if the
system supports.

-config RESCTRL_FS_PSEUDO_LOCK
- bool
- help
- Software mechanism to pin data in a cache portion using
- micro-architecture specific knowledge.
-
if X86_32
config X86_BIGSMP
bool "Support for big SMP systems with more than 8 CPUs"
diff --git a/fs/Kconfig b/fs/Kconfig
index a46b0cbc4d8f..d8a36383b6dc 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -331,6 +331,7 @@ 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/sysv/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index 6ecc9b0a53f2..da6e2d028722 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -129,3 +129,4 @@ obj-$(CONFIG_EFIVAR_FS) += efivarfs/
obj-$(CONFIG_EROFS_FS) += erofs/
obj-$(CONFIG_VBOXSF_FS) += vboxsf/
obj-$(CONFIG_ZONEFS_FS) += zonefs/
+obj-$(CONFIG_RESCTRL_FS) += resctrl/
diff --git a/fs/resctrl/Kconfig b/fs/resctrl/Kconfig
new file mode 100644
index 000000000000..a5fbda54d32f
--- /dev/null
+++ b/fs/resctrl/Kconfig
@@ -0,0 +1,36 @@
+config RESCTRL_FS
+ bool "CPU Resource Control Filesystem (resctrl)"
+ depends on ARCH_HAS_CPU_RESCTRL
+ select KERNFS
+ select PROC_CPU_RESCTRL if PROC_FS
+ help
+ Some architectures provide hardware facilities to group tasks and
+ monitor and control their usage of memory system resources such as
+ caches and memory bandwidth. Examples of such facilities include
+ Intel's Resource Director Technology (Intel(R) RDT) and AMD's
+ Platform Quality of Service (AMD QoS).
+
+ If your system has the necessary support and you want to be able to
+ assign tasks to groups and manipulate the associated resource
+ monitors and controls from userspace, say Y here to get a mountable
+ 'resctrl' filesystem that lets you do just that.
+
+ If nothing mounts or prods the 'resctrl' filesystem, resource
+ controls and monitors are left in a quiescent, permissive state.
+
+ If unsure, it is safe to say N.
+
+ See <file:Documentation/arch/x86/resctrl.rst> for more information.
+
+config RESCTRL_FS_PSEUDO_LOCK
+ bool
+ help
+ Software mechanism to pin data in a cache portion using
+ micro-architecture specific knowledge.
+
+config RESCTRL_RMID_DEPENDS_ON_CLOSID
+ bool
+ help
+ Enable by the architecture when the RMID values depend on the CLOSID.
+ This causes the closid allocator to search for CLOSID with clean
+ RMID.
diff --git a/fs/resctrl/Makefile b/fs/resctrl/Makefile
new file mode 100644
index 000000000000..ee8c4463317a
--- /dev/null
+++ b/fs/resctrl/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_RESCTRL_FS) += rdtgroup.o ctrlmondata.o monitor.o
+obj-$(CONFIG_RESCTRL_FS_PSEUDO_LOCK) += pseudo_lock.o
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/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
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 189e6dbce33c..819007e74ad3 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
--
2.34.1

Next message: Dave Martin: "[PATCH v2 30/35] x86/resctrl: Squelch whitespace anomalies in resctrl core code"
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