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    Subject[patch v3 31/36] x86/apic: Provide cpu_primary_thread mask
    Date
    From: Thomas Gleixner <tglx@linutronix.de>

    Make the primary thread tracking CPU mask based in preparation for simpler
    handling of parallel bootup.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Tested-by: Michael Kelley <mikelley@microsoft.com>


    ---
    arch/x86/include/asm/apic.h | 2 --
    arch/x86/include/asm/topology.h | 19 +++++++++++++++----
    arch/x86/kernel/apic/apic.c | 20 +++++++++-----------
    arch/x86/kernel/smpboot.c | 12 +++---------
    4 files changed, 27 insertions(+), 26 deletions(-)
    ---

    --- a/arch/x86/include/asm/apic.h
    +++ b/arch/x86/include/asm/apic.h
    @@ -506,10 +506,8 @@ extern int default_check_phys_apicid_pre
    #endif /* CONFIG_X86_LOCAL_APIC */

    #ifdef CONFIG_SMP
    -bool apic_id_is_primary_thread(unsigned int id);
    void apic_smt_update(void);
    #else
    -static inline bool apic_id_is_primary_thread(unsigned int id) { return false; }
    static inline void apic_smt_update(void) { }
    #endif

    --- a/arch/x86/include/asm/topology.h
    +++ b/arch/x86/include/asm/topology.h
    @@ -31,9 +31,9 @@
    * CONFIG_NUMA.
    */
    #include <linux/numa.h>
    +#include <linux/cpumask.h>

    #ifdef CONFIG_NUMA
    -#include <linux/cpumask.h>

    #include <asm/mpspec.h>
    #include <asm/percpu.h>
    @@ -139,9 +139,20 @@ static inline int topology_max_smt_threa
    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_is_primary_thread(unsigned int cpu);
    bool topology_smt_supported(void);
    -#else
    +
    +extern struct cpumask __cpu_primary_thread_mask;
    +#define cpu_primary_thread_mask ((const struct cpumask *)&__cpu_primary_thread_mask)
    +
    +/**
    + * topology_is_primary_thread - Check whether CPU is the primary SMT thread
    + * @cpu: CPU to check
    + */
    +static inline bool topology_is_primary_thread(unsigned int cpu)
    +{
    + return cpumask_test_cpu(cpu, cpu_primary_thread_mask);
    +}
    +#else /* CONFIG_SMP */
    #define topology_max_packages() (1)
    static inline int
    topology_update_package_map(unsigned int apicid, unsigned int cpu) { return 0; }
    @@ -152,7 +163,7 @@ static inline int topology_max_die_per_p
    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
    +#endif /* !CONFIG_SMP */

    static inline void arch_fix_phys_package_id(int num, u32 slot)
    {
    --- a/arch/x86/kernel/apic/apic.c
    +++ b/arch/x86/kernel/apic/apic.c
    @@ -2386,20 +2386,16 @@ bool arch_match_cpu_phys_id(int cpu, u64
    }

    #ifdef CONFIG_SMP
    -/**
    - * apic_id_is_primary_thread - Check whether APIC ID belongs to a primary thread
    - * @apicid: APIC ID to check
    - */
    -bool apic_id_is_primary_thread(unsigned int apicid)
    +static void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid)
    {
    - u32 mask;
    -
    - if (smp_num_siblings == 1)
    - return true;
    /* Isolate the SMT bit(s) in the APICID and check for 0 */
    - mask = (1U << (fls(smp_num_siblings) - 1)) - 1;
    - return !(apicid & mask);
    + u32 mask = (1U << (fls(smp_num_siblings) - 1)) - 1;
    +
    + if (smp_num_siblings == 1 || !(apicid & mask))
    + cpumask_set_cpu(cpu, &__cpu_primary_thread_mask);
    }
    +#else
    +static inline void cpu_mark_primary_thread(unsigned int cpu, unsigned int apicid) { }
    #endif

    /*
    @@ -2544,6 +2540,8 @@ int generic_processor_info(int apicid, i
    set_cpu_present(cpu, true);
    num_processors++;

    + cpu_mark_primary_thread(cpu, apicid);
    +
    return cpu;
    }

    --- a/arch/x86/kernel/smpboot.c
    +++ b/arch/x86/kernel/smpboot.c
    @@ -102,6 +102,9 @@ EXPORT_PER_CPU_SYMBOL(cpu_die_map);
    DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
    EXPORT_PER_CPU_SYMBOL(cpu_info);

    +/* CPUs which are the primary SMT threads */
    +struct cpumask __cpu_primary_thread_mask __read_mostly;
    +
    /* Representing CPUs for which sibling maps can be computed */
    static cpumask_var_t cpu_sibling_setup_mask;

    @@ -283,15 +286,6 @@ static void notrace start_secondary(void
    }

    /**
    - * topology_is_primary_thread - Check whether CPU is the primary SMT thread
    - * @cpu: CPU to check
    - */
    -bool topology_is_primary_thread(unsigned int 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)

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