sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig

JIRA: https://issues.redhat.com/browse/RHEL-118964
Conflicts:  Dropped hunks for usupported architectures. Some context
differences in other Kconfig files.

commit 7bd291a
Author: Peter Zijlstra <peterz@infradead.org>
Date:   Tue Aug 26 11:08:57 2025 +0200

    sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig

    Like many Kconfig symbols, SCHED_{SMT,CLUSTER,MC} are duplicated
    across arch/*/Kconfig. Try and clean up a little.

    Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
    Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com> # powerpc
    Link: https://lkml.kernel.org/r/20250826094358.GG3245006@noisy.programming.kicks-ass.net

Signed-off-by: Phil Auld <pauld@redhat.com>

Author: auldp

arch/Kconfig

@@ -33,6 +33,44 @@ config HOTPLUG_SMT
 config SMT_NUM_THREADS_DYNAMIC
 	bool
 
+config ARCH_SUPPORTS_SCHED_SMT
+	bool
+
+config ARCH_SUPPORTS_SCHED_CLUSTER
+	bool
+
+config ARCH_SUPPORTS_SCHED_MC
+	bool
+
+config SCHED_SMT
+	bool "SMT (Hyperthreading) scheduler support"
+	depends on ARCH_SUPPORTS_SCHED_SMT
+	default y
+	help
+	  Improves the CPU scheduler's decision making when dealing with
+	  MultiThreading at a cost of slightly increased overhead in some
+	  places. If unsure say N here.
+
+config SCHED_CLUSTER
+	bool "Cluster scheduler support"
+	depends on ARCH_SUPPORTS_SCHED_CLUSTER
+	default y
+	help
+	  Cluster scheduler support improves the CPU scheduler's decision
+	  making when dealing with machines that have clusters of CPUs.
+	  Cluster usually means a couple of CPUs which are placed closely
+	  by sharing mid-level caches, last-level cache tags or internal
+	  busses.
+
+config SCHED_MC
+	bool "Multi-Core Cache (MC) scheduler support"
+	depends on ARCH_SUPPORTS_SCHED_MC
+	default y
+	help
+	  Multi-core scheduler support improves the CPU scheduler's decision
+	  making when dealing with multi-core CPU chips at a cost of slightly
+	  increased overhead in some places. If unsure say N here.
+
 # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL
 config HOTPLUG_CORE_SYNC
 	bool

arch/arm64/Kconfig

@@ -99,6 +99,9 @@ config ARM64
 	select ARCH_SUPPORTS_PER_VMA_LOCK
 	select ARCH_SUPPORTS_HUGE_PFNMAP if TRANSPARENT_HUGEPAGE
 	select ARCH_SUPPORTS_RT
+	select ARCH_SUPPORTS_SCHED_SMT
+	select ARCH_SUPPORTS_SCHED_CLUSTER
+	select ARCH_SUPPORTS_SCHED_MC
 	select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
 	select ARCH_WANT_DEFAULT_BPF_JIT
@@ -1448,29 +1451,6 @@ config CPU_LITTLE_ENDIAN
 
 endchoice
 
-config SCHED_MC
-	bool "Multi-core scheduler support"
-	help
-	  Multi-core scheduler support improves the CPU scheduler's decision
-	  making when dealing with multi-core CPU chips at a cost of slightly
-	  increased overhead in some places. If unsure say N here.
-
-config SCHED_CLUSTER
-	bool "Cluster scheduler support"
-	help
-	  Cluster scheduler support improves the CPU scheduler's decision
-	  making when dealing with machines that have clusters of CPUs.
-	  Cluster usually means a couple of CPUs which are placed closely
-	  by sharing mid-level caches, last-level cache tags or internal
-	  busses.
-
-config SCHED_SMT
-	bool "SMT scheduler support"
-	help
-	  Improves the CPU scheduler's decision making when dealing with
-	  MultiThreading at a cost of slightly increased overhead in some
-	  places. If unsure say N here.
-
 config NR_CPUS
 	int "Maximum number of CPUs (2-4096)"
 	range 2 4096

arch/powerpc/Kconfig

@@ -146,6 +146,9 @@ config PPC
 	select ARCH_STACKWALK
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC	if PPC_BOOK3S || PPC_8xx || 40x
+	select ARCH_SUPPORTS_SCHED_MC           if SMP
+	select ARCH_SUPPORTS_SCHED_SMT          if PPC64 && SMP
+	select SCHED_MC                         if ARCH_SUPPORTS_SCHED_MC
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF		if PPC64
 	select ARCH_USE_MEMTEST
@@ -845,18 +848,6 @@ config PPC_PROT_SAO_LPAR
 config PPC_COPRO_BASE
 	bool
 
-config SCHED_SMT
-	bool "SMT (Hyperthreading) scheduler support"
-	depends on PPC64 && SMP
-	help
-	  SMT scheduler support improves the CPU scheduler's decision making
-	  when dealing with POWER5 cpus at a cost of slightly increased
-	  overhead in some places. If unsure say N here.
-
-config SCHED_MC
-	def_bool y
-	depends on SMP
-
 config PPC_DENORMALISATION
 	bool "PowerPC denormalisation exception handling"
 	depends on PPC_BOOK3S_64

arch/s390/Kconfig

@@ -499,15 +499,11 @@ config NODES_SHIFT
 	depends on NUMA
 	default "1"
 
-config SCHED_SMT
-	def_bool n
-
-config SCHED_MC
-	def_bool n
-
 config SCHED_TOPOLOGY
 	def_bool y
 	prompt "Topology scheduler support"
+	select ARCH_SUPPORTS_SCHED_SMT
+	select ARCH_SUPPORTS_SCHED_MC
 	select SCHED_SMT
 	select SCHED_MC
 	help

arch/x86/Kconfig

@@ -308,6 +308,10 @@ config X86
 	select FUNCTION_ALIGNMENT_4B
 	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
 	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
+	select ARCH_SUPPORTS_SCHED_SMT          if SMP
+	select SCHED_SMT                        if SMP
+	select ARCH_SUPPORTS_SCHED_CLUSTER      if SMP
+	select ARCH_SUPPORTS_SCHED_MC           if SMP
 
 config INSTRUCTION_DECODER
 	def_bool y
@@ -1030,29 +1034,6 @@ config NR_CPUS
 	  This is purely to save memory: each supported CPU adds about 8KB
 	  to the kernel image.
 
-config SCHED_CLUSTER
-	bool "Cluster scheduler support"
-	depends on SMP
-	default y
-	help
-	  Cluster scheduler support improves the CPU scheduler's decision
-	  making when dealing with machines that have clusters of CPUs.
-	  Cluster usually means a couple of CPUs which are placed closely
-	  by sharing mid-level caches, last-level cache tags or internal
-	  busses.
-
-config SCHED_SMT
-	def_bool y if SMP
-
-config SCHED_MC
-	def_bool y
-	prompt "Multi-core scheduler support"
-	depends on SMP
-	help
-	  Multi-core scheduler support improves the CPU scheduler's decision
-	  making when dealing with multi-core CPU chips at a cost of slightly
-	  increased overhead in some places. If unsure say N here.
-
 config SCHED_MC_PRIO
 	bool "CPU core priorities scheduler support"
 	depends on SCHED_MC && CPU_SUP_INTEL