linux-kernel - [tip: smp/core] cpu/SMT: Remove topology_smt

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Date:   Fri, 28 Jul 2023 07:57:54 -0000
From:   "tip-bot2 for Laurent Dufour" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Zhang Rui <rui.zhang@...el.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: smp/core] cpu/SMT: Remove topology_smt_supported()

The following commit has been merged into the smp/core branch of tip:

Commit-ID:     91b4a7dbfe05ddb6fd3cf78cc11fb5ed64d3af90
Gitweb:        https://git.kernel.org/tip/91b4a7dbfe05ddb6fd3cf78cc11fb5ed64d3af90
Author:        Laurent Dufour <ldufour@...ux.ibm.com>
AuthorDate:    Wed, 05 Jul 2023 16:51:38 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 28 Jul 2023 09:53:37 +02:00

cpu/SMT: Remove topology_smt_supported()

Since the maximum number of threads is now passed to cpu_smt_set_num_threads(),
checking that value is enough to know whether SMT is supported.

Suggested-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Laurent Dufour <ldufour@...ux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Zhang Rui <rui.zhang@...el.com>
Link: https://lore.kernel.org/r/20230705145143.40545-6-ldufour@linux.ibm.com

---
 arch/x86/include/asm/topology.h | 2 --
 arch/x86/kernel/smpboot.c       | 8 --------
 kernel/cpu.c                    | 4 ++--
 3 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index ae49ed4..3235ba1 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -141,7 +141,6 @@ static inline int topology_max_smt_threads(void)
 int topology_update_package_map(unsigned int apicid, unsigned int cpu);
 int topology_update_die_map(unsigned int dieid, unsigned int cpu);
 int topology_phys_to_logical_pkg(unsigned int pkg);
-bool topology_smt_supported(void);
 
 extern struct cpumask __cpu_primary_thread_mask;
 #define cpu_primary_thread_mask ((const struct cpumask *)&__cpu_primary_thread_mask)
@@ -164,7 +163,6 @@ static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; }
 static inline int topology_max_die_per_package(void) { return 1; }
 static inline int topology_max_smt_threads(void) { return 1; }
 static inline bool topology_is_primary_thread(unsigned int cpu) { return true; }
-static inline bool topology_smt_supported(void) { return false; }
 #endif /* !CONFIG_SMP */
 
 static inline void arch_fix_phys_package_id(int num, u32 slot)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index e1aa2cd..d4e897b 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -327,14 +327,6 @@ static void notrace start_secondary(void *unused)
 }
 
 /**
- * topology_smt_supported - Check whether SMT is supported by the CPUs
- */
-bool topology_smt_supported(void)
-{
-	return smp_num_siblings > 1;
-}
-
-/**
  * topology_phys_to_logical_pkg - Map a physical package id to a logical
  * @phys_pkg:	The physical package id to map
  *
diff --git a/kernel/cpu.c b/kernel/cpu.c
index d7dd535..70add05 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -621,7 +621,7 @@ void __init cpu_smt_set_num_threads(unsigned int num_threads,
 {
 	WARN_ON(!num_threads || (num_threads > max_threads));
 
-	if (!topology_smt_supported())
+	if (max_threads == 1)
 		cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
 
 	cpu_smt_max_threads = max_threads;
@@ -1801,7 +1801,7 @@ early_param("cpuhp.parallel", parallel_bringup_parse_param);
 
 static inline bool cpuhp_smt_aware(void)
 {
-	return topology_smt_supported();
+	return cpu_smt_max_threads > 1;
 }
 
 static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)