FreeBSD/Linux Kernel Cross Reference
sys/sys/smp.h

     /*-
      * SPDX-License-Identifier: Beerware
      *
      * ----------------------------------------------------------------------------
      * "THE BEER-WARE LICENSE" (Revision 42):
      * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
      * can do whatever you want with this stuff. If we meet some day, and you think
      * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
      * ----------------------------------------------------------------------------
     *
     * $FreeBSD$
     */
    
    #ifndef _SYS_SMP_H_
    #define _SYS_SMP_H_
    
    #ifdef _KERNEL
    
    #ifndef LOCORE
    
    #include <sys/cpuset.h>
    #include <sys/queue.h>
    
    /*
     * Types of nodes in the topological tree.
     */
    typedef enum {
            /* No node has this type; can be used in topo API calls. */
            TOPO_TYPE_DUMMY,
            /* Processing unit aka computing unit aka logical CPU. */
            TOPO_TYPE_PU,
            /* Physical subdivision of a package. */
            TOPO_TYPE_CORE,
            /* CPU L1/L2/L3 cache. */
            TOPO_TYPE_CACHE,
            /* Package aka chip, equivalent to socket. */
            TOPO_TYPE_PKG,
            /* NUMA node. */
            TOPO_TYPE_NODE,
            /* Other logical or physical grouping of PUs. */
            /* E.g. PUs on the same dye, or PUs sharing an FPU. */
            TOPO_TYPE_GROUP,
            /* The whole system. */
            TOPO_TYPE_SYSTEM
    } topo_node_type;
    
    /* Hardware indenitifier of a topology component. */
    typedef unsigned int hwid_t;
    /* Logical CPU idenitifier. */
    typedef int cpuid_t;
    
    /* A node in the topology. */
    struct topo_node {
            struct topo_node                        *parent;
            TAILQ_HEAD(topo_children, topo_node)    children;
            TAILQ_ENTRY(topo_node)                  siblings;
            cpuset_t                                cpuset;
            topo_node_type                          type;
            uintptr_t                               subtype;
            hwid_t                                  hwid;
            cpuid_t                                 id;
            int                                     nchildren;
            int                                     cpu_count;
    };
    
    /*
     * Scheduling topology of a NUMA or SMP system.
     *
     * The top level topology is an array of pointers to groups.  Each group
     * contains a bitmask of cpus in its group or subgroups.  It may also
     * contain a pointer to an array of child groups.
     *
     * The bitmasks at non leaf groups may be used by consumers who support
     * a smaller depth than the hardware provides.
     *
     * The topology may be omitted by systems where all CPUs are equal.
     */
    
    struct cpu_group {
            struct cpu_group *cg_parent;    /* Our parent group. */
            struct cpu_group *cg_child;     /* Optional children groups. */
            cpuset_t        cg_mask;        /* Mask of cpus in this group. */
            int32_t         cg_count;       /* Count of cpus in this group. */
            int16_t         cg_children;    /* Number of children groups. */
            int8_t          cg_level;       /* Shared cache level. */
            int8_t          cg_flags;       /* Traversal modifiers. */
    };
    
    typedef struct cpu_group *cpu_group_t;
    
    /*
     * Defines common resources for CPUs in the group.  The highest level
     * resource should be used when multiple are shared.
     */
    #define CG_SHARE_NONE   0
    #define CG_SHARE_L1     1
    #define CG_SHARE_L2     2
    #define CG_SHARE_L3     3
    
   #define MAX_CACHE_LEVELS        CG_SHARE_L3
   
   /*
    * Behavior modifiers for load balancing and affinity.
    */
   #define CG_FLAG_HTT     0x01            /* Schedule the alternate core last. */
   #define CG_FLAG_SMT     0x02            /* New age htt, less crippled. */
   #define CG_FLAG_THREAD  (CG_FLAG_HTT | CG_FLAG_SMT)     /* Any threading. */
   
   /*
    * Convenience routines for building and traversing topologies.
    */
   #ifdef SMP
   void topo_init_node(struct topo_node *node);
   void topo_init_root(struct topo_node *root);
   struct topo_node * topo_add_node_by_hwid(struct topo_node *parent, int hwid,
       topo_node_type type, uintptr_t subtype);
   struct topo_node * topo_find_node_by_hwid(struct topo_node *parent, int hwid,
       topo_node_type type, uintptr_t subtype);
   void topo_promote_child(struct topo_node *child);
   struct topo_node * topo_next_node(struct topo_node *top,
       struct topo_node *node);
   struct topo_node * topo_next_nonchild_node(struct topo_node *top,
       struct topo_node *node);
   void topo_set_pu_id(struct topo_node *node, cpuid_t id);
   
   enum topo_level {
           TOPO_LEVEL_PKG = 0,
           /*
            * Some systems have useful sub-package core organizations.  On these,
            * a package has one or more subgroups.  Each subgroup contains one or
            * more cache groups (cores that share a last level cache).
            */
           TOPO_LEVEL_GROUP,
           TOPO_LEVEL_CACHEGROUP,
           TOPO_LEVEL_CORE,
           TOPO_LEVEL_THREAD,
           TOPO_LEVEL_COUNT        /* Must be last */
   };
   struct topo_analysis {
           int entities[TOPO_LEVEL_COUNT];
   };
   int topo_analyze(struct topo_node *topo_root, int all,
       struct topo_analysis *results);
   
   #define TOPO_FOREACH(i, root)   \
           for (i = root; i != NULL; i = topo_next_node(root, i))
   
   struct cpu_group *smp_topo(void);
   struct cpu_group *smp_topo_alloc(u_int count);
   struct cpu_group *smp_topo_none(void);
   struct cpu_group *smp_topo_1level(int l1share, int l1count, int l1flags);
   struct cpu_group *smp_topo_2level(int l2share, int l2count, int l1share,
       int l1count, int l1flags);
   struct cpu_group *smp_topo_find(struct cpu_group *top, int cpu);
   
   extern void (*cpustop_restartfunc)(void);
   extern int smp_cpus;
   /* The suspend/resume cpusets are x86 only, but minimize ifdefs. */
   extern volatile cpuset_t resuming_cpus; /* woken up cpus in suspend pen */
   extern volatile cpuset_t started_cpus;  /* cpus to let out of stop pen */
   extern volatile cpuset_t stopped_cpus;  /* cpus in stop pen */
   extern volatile cpuset_t suspended_cpus; /* cpus [near] sleeping in susp pen */
   extern volatile cpuset_t toresume_cpus; /* cpus to let out of suspend pen */
   extern cpuset_t hlt_cpus_mask;          /* XXX 'mask' is detail in old impl */
   extern cpuset_t logical_cpus_mask;
   #endif /* SMP */
   
   extern u_int mp_maxid;
   extern int mp_maxcpus;
   extern int mp_ncores;
   extern int mp_ncpus;
   extern volatile int smp_started;
   extern int smp_threads_per_core;
   
   extern cpuset_t all_cpus;
   extern cpuset_t cpuset_domain[MAXMEMDOM];       /* CPUs in each NUMA domain. */
   
   /*
    * Macro allowing us to determine whether a CPU is absent at any given
    * time, thus permitting us to configure sparse maps of cpuid-dependent
    * (per-CPU) structures.
    */
   #define CPU_ABSENT(x_cpu)       (!CPU_ISSET(x_cpu, &all_cpus))
   
   /*
    * Macros to iterate over non-absent CPUs.  CPU_FOREACH() takes an
    * integer iterator and iterates over the available set of CPUs.
    * CPU_FIRST() returns the id of the first non-absent CPU.  CPU_NEXT()
    * returns the id of the next non-absent CPU.  It will wrap back to
    * CPU_FIRST() once the end of the list is reached.  The iterators are
    * currently implemented via inline functions.
    */
   #define CPU_FOREACH(i)                                                  \
           for ((i) = 0; (i) <= mp_maxid; (i)++)                           \
                   if (!CPU_ABSENT((i)))
   
   static __inline int
   cpu_first(void)
   {
           int i;
   
           for (i = 0;; i++)
                   if (!CPU_ABSENT(i))
                           return (i);
   }
   
   static __inline int
   cpu_next(int i)
   {
   
           for (;;) {
                   i++;
                   if (i > mp_maxid)
                           i = 0;
                   if (!CPU_ABSENT(i))
                           return (i);
           }
   }
   
   #define CPU_FIRST()     cpu_first()
   #define CPU_NEXT(i)     cpu_next((i))
   
   #ifdef SMP
   /*
    * Machine dependent functions used to initialize MP support.
    *
    * The cpu_mp_probe() should check to see if MP support is present and return
    * zero if it is not or non-zero if it is.  If MP support is present, then
    * cpu_mp_start() will be called so that MP can be enabled.  This function
    * should do things such as startup secondary processors.  It should also
    * setup mp_ncpus, all_cpus, and smp_cpus.  It should also ensure that
    * smp_started is initialized at the appropriate time.
    * Once cpu_mp_start() returns, machine independent MP startup code will be
    * executed and a simple message will be output to the console.  Finally,
    * cpu_mp_announce() will be called so that machine dependent messages about
    * the MP support may be output to the console if desired.
    *
    * The cpu_setmaxid() function is called very early during the boot process
    * so that the MD code may set mp_maxid to provide an upper bound on CPU IDs
    * that other subsystems may use.  If a platform is not able to determine
    * the exact maximum ID that early, then it may set mp_maxid to MAXCPU - 1.
    */
   struct thread;
   
   struct cpu_group *cpu_topo(void);
   void    cpu_mp_announce(void);
   int     cpu_mp_probe(void);
   void    cpu_mp_setmaxid(void);
   void    cpu_mp_start(void);
   
   void    forward_signal(struct thread *);
   int     restart_cpus(cpuset_t);
   int     stop_cpus(cpuset_t);
   int     stop_cpus_hard(cpuset_t);
   #if defined(__amd64__) || defined(__i386__)
   int     suspend_cpus(cpuset_t);
   int     resume_cpus(cpuset_t);
   #endif
   
   void    smp_rendezvous_action(void);
   extern  struct mtx smp_ipi_mtx;
   
   #endif /* SMP */
   
   int     quiesce_all_cpus(const char *, int);
   int     quiesce_cpus(cpuset_t, const char *, int);
   void    smp_no_rendezvous_barrier(void *);
   void    smp_rendezvous(void (*)(void *), 
                          void (*)(void *),
                          void (*)(void *),
                          void *arg);
   void    smp_rendezvous_cpus(cpuset_t,
                          void (*)(void *), 
                          void (*)(void *),
                          void (*)(void *),
                          void *arg);
   #endif /* !LOCORE */
   #endif /* _KERNEL */
   #endif /* _SYS_SMP_H_ */

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