ランキュー初期化
===========================

sched_4bsd_setup
---------------------------

- sys/kern/sched_4bsd.c

.. code-block:: c

    static void
    sched_4bsd_setup(void)
    {
        /*
        * Decay 95% of `ts_pctcpu' in 60 seconds; see CCPU_SHIFT
        * before changing.
        */
        ccpu = 0.95122942450071400909 * FSCALE;	/* exp(-1/20) */

        setup_runqs();

        /* Account for thread0. */
        sched_load_add();

        ast_register(TDA_SCHED_PRIV, ASTR_UNCOND, 0, maybe_resched_ast);
    }


setup_runqs
---------------------------

- sys/kern/sched_4bsd.c

.. code-block:: c

    static void
    setup_runqs(void)
    {
    #ifdef SMP
        int i;

        for (i = 0; i < MAXCPU; ++i)
            runq_init(&runq_pcpu[i]);
    #endif

        runq_init(&runq);
    }


runq_init
---------------------------

- sys/kern/kern_switch.c

.. code-block:: c

    /*
    * Initialize a run structure.
    */
    void
    runq_init(struct runq *rq)
    {
        int i;

        bzero(rq, sizeof(*rq));
        for (i = 0; i < RQ_NQS; i++)
            TAILQ_INIT(&rq->rq_queues[i]);
    }


TAILQ_INIT
---------------------------

- sys/sys/queue.h

.. code-block:: c

    #define TAILQ_FIRST(head)	((head)->tqh_first)

    #ifdef QUEUE_MACRO_DEBUG_TRACE
    #define QMD_TRACE_HEAD(head) do {				\
        (head)->trace.prevline = (head)->trace.lastline;	\
        (head)->trace.prevfile = (head)->trace.lastfile;	\
        (head)->trace.lastline = __LINE__;			\
        (head)->trace.lastfile = __FILE__;			\
    } while (0)
    #else
    #define QMD_TRACE_HEAD(head)
    #endif

    #define TAILQ_INIT(head) do {				\
        TAILQ_FIRST((head)) = NULL;				\
        (head)->tqh_last = &TAILQ_FIRST((head));		\
        QMD_TRACE_HEAD(head);					\
    } while (0)


sched_load_add
---------------------------

- sys/kern/sched_4bsd.c

.. code-block:: c

    static __inline void
    sched_load_add(void)
    {

        sched_tdcnt++;
        KTR_COUNTER0(KTR_SCHED, "load", "global load", sched_tdcnt);
        SDT_PROBE2(sched, , , load__change, NOCPU, sched_tdcnt);
    }