Message-ID: <8cd265e2-fa14-46f4-a018-edfcf73f8a92@nvidia.com>
Date: Thu, 6 Mar 2025 18:16:28 -0800
From: Fenghua Yu <fenghuay@...dia.com>
To: James Morse <james.morse@....com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Cc: Reinette Chatre <reinette.chatre@...el.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, H Peter Anvin <hpa@...or.com>,
 Babu Moger <Babu.Moger@....com>, shameerali.kolothum.thodi@...wei.com,
 D Scott Phillips OS <scott@...amperecomputing.com>,
 carl@...amperecomputing.com, lcherian@...vell.com,
 bobo.shaobowang@...wei.com, tan.shaopeng@...itsu.com,
 baolin.wang@...ux.alibaba.com, Jamie Iles <quic_jiles@...cinc.com>,
 Xin Hao <xhao@...ux.alibaba.com>, peternewman@...gle.com,
 dfustini@...libre.com, amitsinght@...vell.com,
 David Hildenbrand <david@...hat.com>, Rex Nie <rex.nie@...uarmicro.com>,
 Dave Martin <dave.martin@....com>, Koba Ko <kobak@...dia.com>,
 Shanker Donthineni <sdonthineni@...dia.com>,
 Shaopeng Tan <tan.shaopeng@...fujitsu.com>, Tony Luck <tony.luck@...el.com>
Subject: Re: [PATCH v7 40/49] fs/resctrl: Add boiler plate for external
 resctrl code


On 2/28/25 11:59, James Morse wrote:
> 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@....com>
> Signed-off-by: Dave Martin <Dave.Martin@....com>
> Signed-off-by: James Morse <james.morse@....com>
> Tested-by: Carl Worth <carl@...amperecomputing.com> # arm64
> Tested-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Reviewed-by: Tony Luck <tony.luck@...el.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 3487ac429a9a..433ba4a5a84a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19881,6 +19881,7 @@ 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 b8a4ff365582..2778a7859c11 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 1a89574a58f7..ea29d22a621f 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -503,8 +503,9 @@ 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.
> @@ -522,12 +523,6 @@ 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 16c1a391d012..ee50b7375717 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 90e7f8754b91..fcd3c41db554 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 5c14f4999d55..69dff2bb2c09 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 4209d78b7aae..4108c0de298c 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 64d420e3c475..709e4d6656e2 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -334,6 +334,7 @@ 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 15df0a923d3a..73512f13e969 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -129,3 +129,4 @@ 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

If merge patch 45 and 46 together to fix the pseudo_lock_trace.h 
compilation fatal issue, it's unnecessary to create pseudo_lock_trace.h 
here (and then the empty pseudo_lock_trace.h file will be deleted later 
in merged patch 45).

> 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

Other than that,

Reviewed-by: Fenghua Yu <fenghua.yu@...el.com>

Thanks.

-Fenghua

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