b0f865c1f3
halt state that minimizes power consumption while still preserving cache and TLB coherency. Halting the processor is not conditional at this time. Tested with UP and SMP kernels.
127 lines
2.5 KiB
C
127 lines
2.5 KiB
C
/*-
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* Copyright (c) 2000, All rights reserved. See /usr/src/COPYRIGHT
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ktrace.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/kthread.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/pcpu.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/sched.h>
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#include <sys/smp.h>
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#include <sys/unistd.h>
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#ifdef KTRACE
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#include <sys/uio.h>
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#include <sys/ktrace.h>
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#endif
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static void idle_setup(void *dummy);
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SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
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static void idle_proc(void *dummy);
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/*
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* Setup per-cpu idle process contexts. The AP's shouldn't be running or
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* accessing their idle processes at this point, so don't bother with
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* locking.
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*/
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static void
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idle_setup(void *dummy)
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{
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#ifdef SMP
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struct pcpu *pc;
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#endif
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struct proc *p;
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struct thread *td;
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int error;
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#ifdef SMP
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SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
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error = kthread_create(idle_proc, NULL, &p,
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RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid);
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pc->pc_idlethread = FIRST_THREAD_IN_PROC(p);
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if (pc->pc_curthread == NULL) {
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pc->pc_curthread = pc->pc_idlethread;
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pc->pc_idlethread->td_critnest = 0;
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}
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#else
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error = kthread_create(idle_proc, NULL, &p,
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RFSTOPPED | RFHIGHPID, 0, "idle");
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PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p));
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#endif
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if (error)
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panic("idle_setup: kthread_create error %d\n", error);
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PROC_LOCK(p);
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p->p_flag |= P_NOLOAD;
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mtx_lock_spin(&sched_lock);
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p->p_state = PRS_NORMAL;
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td = FIRST_THREAD_IN_PROC(p);
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td->td_state = TDS_CAN_RUN;
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td->td_flags |= TDF_IDLETD;
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mtx_unlock_spin(&sched_lock);
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PROC_UNLOCK(p);
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#ifdef SMP
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}
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#endif
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}
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/*
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* idle process context
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*/
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static void
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idle_proc(void *dummy)
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{
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#ifdef DIAGNOSTIC
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int count;
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#endif
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struct thread *td;
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struct proc *p;
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td = curthread;
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p = td->td_proc;
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for (;;) {
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mtx_assert(&Giant, MA_NOTOWNED);
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#ifdef DIAGNOSTIC
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count = 0;
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while (count >= 0 && sched_runnable() == 0) {
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#else
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while (sched_runnable() == 0) {
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#endif
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/*
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* This is a good place to put things to be done in
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* the background, including sanity checks.
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*/
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#ifdef DIAGNOSTIC
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if (count++ < 0)
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CTR0(KTR_PROC, "idle_proc: timed out waiting"
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" for a process");
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#endif
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#if defined(__i386__) || defined(__ia64__)
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cpu_idle();
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#endif
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}
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mtx_lock_spin(&sched_lock);
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p->p_stats->p_ru.ru_nvcsw++;
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td->td_state = TDS_CAN_RUN;
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mi_switch();
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mtx_unlock_spin(&sched_lock);
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}
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}
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