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x86/topology: Provide topology_smt_supported()

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Provide information whether SMT is supoorted by the CPUs. Preparatory patch
for SMT control mechanism.

Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2018-06-21 10:37:20 +02:00
parent 6a4d2657e0
commit f048c399e0
2 changed files with 10 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/include/asm/topology.h
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@ -125,6 +125,7 @@ static inline int topology_max_smt_threads(void)
int topology_update_package_map(unsigned int apicid, unsigned int cpu); int topology_update_package_map(unsigned int apicid, unsigned int cpu);
int topology_phys_to_logical_pkg(unsigned int pkg); int topology_phys_to_logical_pkg(unsigned int pkg);
bool topology_is_primary_thread(unsigned int cpu); bool topology_is_primary_thread(unsigned int cpu);
bool topology_smt_supported(void);
#else #else
#define topology_max_packages() (1) #define topology_max_packages() (1)
static inline int static inline int
@ -132,6 +133,7 @@ topology_update_package_map(unsigned int apicid, unsigned int cpu) { return 0; }
static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; } static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; }
static inline int topology_max_smt_threads(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_is_primary_thread(unsigned int cpu) { return true; }
static inline bool topology_smt_supported(void) { return false; }
#endif #endif
static inline void arch_fix_phys_package_id(int num, u32 slot) static inline void arch_fix_phys_package_id(int num, u32 slot)

8
arch/x86/kernel/smpboot.c
View file

@ -274,6 +274,14 @@ bool topology_is_primary_thread(unsigned int cpu)
return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu)); return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu));
} }
/**
* 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 * topology_phys_to_logical_pkg - Map a physical package id to a logical
* *