linux-toradex.git/arch/x86/kernel/cpu/resctrl, branch v6.16

x86,fs/resctrl: Remove inappropriate references to cacheinfo in the resctrl subsystem

2025-06-16T19:06:12+00:00

In the resctrl subsystem's Sub-NUMA Cluster (SNC) mode, the rdt_mon_domain
structure representing a NUMA node relies on the cacheinfo interface
(rdt_mon_domain::ci) to store L3 cache information (e.g., shared_cpu_map)
for monitoring. The L3 cache information of a SNC NUMA node determines
which domains are summed for the "top level" L3-scoped events.

rdt_mon_domain::ci is initialized using the first online CPU of a NUMA
node. When this CPU goes offline, its shared_cpu_map is cleared to contain
only the offline CPU itself. Subsequently, attempting to read counters
via smp_call_on_cpu(offline_cpu) fails (and error ignored), returning
zero values for "top-level events" without any error indication.

Replace the cacheinfo references in struct rdt_mon_domain and struct
rmid_read with the cacheinfo ID (a unique identifier for the L3 cache).

rdt_domain_hdr::cpu_mask contains the online CPUs associated with that
domain. When reading "top-level events", select a CPU from
rdt_domain_hdr::cpu_mask and utilize its L3 shared_cpu_map to determine
valid CPUs for reading RMID counter via the MSR interface.

Considering all CPUs associated with the L3 cache improves the chances
of picking a housekeeping CPU on which the counter reading work can be
queued, avoiding an unnecessary IPI.

Fixes: 328ea68874642 ("x86/resctrl: Prepare for new Sub-NUMA Cluster (SNC) monitor files")
Signed-off-by: Qinyun Tan
Signed-off-by: Borislav Petkov (AMD)
Reviewed-by: Reinette Chatre
Tested-by: Tony Luck
Link: https://lore.kernel.org/20250530182053.37502-2-qinyuntan@linux.alibaba.com

Merge tag 'x86_cache_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-05-27T16:53:02+00:00

Pull x86 resource control updates from Borislav Petkov:
 "Carve out the resctrl filesystem-related code into fs/resctrl/ so that
  multiple architectures can share the fs API for manipulating their
  respective hw resource control implementation.

  This is the second step in the work towards sharing the resctrl
  filesystem interface, the next one being plugging ARM's MPAM into the
  aforementioned fs API"

* tag 'x86_cache_for_v6.16_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  MAINTAINERS: Add reviewers for fs/resctrl
  x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl
  x86/resctrl: Always initialise rid field in rdt_resources_all[]
  x86/resctrl: Relax some asm #includes
  x86/resctrl: Prefer alloc(sizeof(*foo)) idiom in rdt_init_fs_context()
  x86/resctrl: Squelch whitespace anomalies in resctrl core code
  x86/resctrl: Move pseudo lock prototypes to include/linux/resctrl.h
  x86/resctrl: Fix types in resctrl_arch_mon_ctx_{alloc,free}() stubs
  x86/resctrl: Move enum resctrl_event_id to resctrl.h
  x86/resctrl: Move the filesystem bits to headers visible to fs/resctrl
  fs/resctrl: Add boiler plate for external resctrl code
  x86/resctrl: Add 'resctrl' to the title of the resctrl documentation
  x86/resctrl: Split trace.h
  x86/resctrl: Expand the width of domid by replacing mon_data_bits
  x86/resctrl: Add end-marker to the resctrl_event_id enum
  x86/resctrl: Move is_mba_sc() out of core.c
  x86/resctrl: Drop __init/__exit on assorted symbols
  x86/resctrl: Resctrl_exit() teardown resctrl but leave the mount point
  x86/resctrl: Check all domains are offline in resctrl_exit()
  x86/resctrl: Rename resctrl_sched_in() to begin with "resctrl_arch_"
  ...

x86,fs/resctrl: Move the resctrl filesystem code to live in /fs/resctrl

2025-05-16T12:36:09+00:00

Resctrl is a filesystem interface to hardware that provides cache
allocation policy and bandwidth control for groups of tasks or CPUs.

To support more than one architecture, resctrl needs to live in /fs/.

Move the code that is concerned with the filesystem interface to
/fs/resctrl.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-25-james.morse@arm.com

x86/resctrl: Always initialise rid field in rdt_resources_all[]

2025-05-16T12:35:22+00:00

x86 has an array, rdt_resources_all[], of all possible resources.
The for-each-resource walkers depend on the rid field of all
resources being initialised.

If the array ever grows due to another architecture adding a resource
type that is not defined on x86, the for-each-resources walkers will
loop forever.

Initialise all the rid values in resctrl_arch_late_init() before
any for-each-resource walker can be called.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Babu Moger 
Tested-by: Shaopeng Tan 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-24-james.morse@arm.com

x86/resctrl: Relax some asm #includes

2025-05-16T12:34:31+00:00

checkpatch.pl identifies some direct #includes of asm headers that
can be satisfied by including the corresponding  header
instead.

Fix them.

No intentional functional change.

Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Reinette Chatre 
Reviewed-by: Fenghua Yu 
Tested-by: Fenghua Yu 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-23-james.morse@arm.com

x86/resctrl: Prefer alloc(sizeof(*foo)) idiom in rdt_init_fs_context()

2025-05-16T12:33:56+00:00

rdt_init_fs_context() sizes a typed allocation using an explicit
sizeof(type) expression, which checkpatch.pl complains about.

Since this code is about to be factored out and made generic, this
is a good opportunity to fix the code to size the allocation based
on the target pointer instead, to reduce the chance of future mis-
maintenance.

Fix it.

No functional change.

Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-22-james.morse@arm.com

x86/resctrl: Squelch whitespace anomalies in resctrl core code

2025-05-16T12:09:18+00:00

checkpatch.pl complains about some whitespace anomalies in the
resctrl core code.

This doesn't matter, but since this code is about to be factored
out and made generic, this is a good opportunity to fix these
issues and so reduce future checkpatch fuzz.

Fix them.

No functional change.

Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
Tested-by: Peter Newman 
Tested-by: Shaopeng Tan 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-21-james.morse@arm.com

x86/resctrl: Move the filesystem bits to headers visible to fs/resctrl

2025-05-16T09:35:23+00:00

Once the filesystem parts of resctrl move to fs/resctrl, it cannot rely
on definitions in x86's internal.h.

Move definitions in internal.h that need to be shared between the
filesystem and architecture code to header files that fs/resctrl can
include.

Doing this separately means the filesystem code only moves between files
of the same name, instead of having these changes mixed in too.

Co-developed-by: Dave Martin 
Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-17-james.morse@arm.com

fs/resctrl: Add boiler plate for external resctrl code

2025-05-16T09:05:40+00:00

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 
Signed-off-by: Dave Martin 
Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
Tested-by: Carl Worth  # arm64
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-16-james.morse@arm.com

x86/resctrl: Split trace.h

2025-05-16T08:47:49+00:00

trace.h contains all the tracepoints. After the move to /fs/resctrl, some
of these will be left behind. All the pseudo_lock tracepoints remain part
of the architecture. The lone tracepoint in monitor.c moves to /fs/resctrl.

Split trace.h so that each C file includes a different trace header file.
This means the trace header files are not modified when they are moved.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov (AMD) 
Reviewed-by: Shaopeng Tan 
Reviewed-by: Tony Luck 
Reviewed-by: Fenghua Yu 
Reviewed-by: Reinette Chatre 
Tested-by: Fenghua Yu 
Tested-by: Shaopeng Tan 
Tested-by: Peter Newman 
Tested-by: Amit Singh Tomar  # arm64
Tested-by: Shanker Donthineni  # arm64
Tested-by: Babu Moger 
Tested-by: Tony Luck 
Link: https://lore.kernel.org/20250515165855.31452-14-james.morse@arm.com