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kern_idle.c revision 1.6 
      1  1.6    ad /*	$NetBSD: kern_idle.c,v 1.6 2007/10/08 20:06:19 ad Exp $	*/
      2  1.2  yamt 
      3  1.2  yamt /*-
      4  1.2  yamt  * Copyright (c)2002, 2006, 2007 YAMAMOTO Takashi,
      5  1.2  yamt  * All rights reserved.
      6  1.2  yamt  *
      7  1.2  yamt  * Redistribution and use in source and binary forms, with or without
      8  1.2  yamt  * modification, are permitted provided that the following conditions
      9  1.2  yamt  * are met:
     10  1.2  yamt  * 1. Redistributions of source code must retain the above copyright
     11  1.2  yamt  *    notice, this list of conditions and the following disclaimer.
     12  1.2  yamt  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.2  yamt  *    notice, this list of conditions and the following disclaimer in the
     14  1.2  yamt  *    documentation and/or other materials provided with the distribution.
     15  1.2  yamt  *
     16  1.2  yamt  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  1.2  yamt  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  1.2  yamt  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  1.2  yamt  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  1.2  yamt  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  1.2  yamt  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  1.2  yamt  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  1.2  yamt  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  1.2  yamt  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  1.2  yamt  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  1.2  yamt  * SUCH DAMAGE.
     27  1.2  yamt  */
     28  1.2  yamt 
     29  1.2  yamt #include <sys/cdefs.h>
     30  1.2  yamt 
     31  1.6    ad __KERNEL_RCSID(0, "$NetBSD: kern_idle.c,v 1.6 2007/10/08 20:06:19 ad Exp $");
     32  1.2  yamt 
     33  1.2  yamt #include <sys/param.h>
     34  1.2  yamt #include <sys/cpu.h>
     35  1.2  yamt #include <sys/idle.h>
     36  1.2  yamt #include <sys/lwp.h>
     37  1.2  yamt #include <sys/lockdebug.h>
     38  1.2  yamt #include <sys/kmem.h>
     39  1.4    ad #include <sys/proc.h>
     40  1.2  yamt 
     41  1.2  yamt #include <uvm/uvm.h>
     42  1.2  yamt #include <uvm/uvm_extern.h>
     43  1.2  yamt 
     44  1.2  yamt #define	PIDLELWP	(MAXPRI + 1)	/* lowest priority */
     45  1.2  yamt 
     46  1.2  yamt void
     47  1.2  yamt idle_loop(void *dummy)
     48  1.2  yamt {
     49  1.2  yamt 	struct cpu_info *ci = curcpu();
     50  1.2  yamt 	struct lwp *l = curlwp;
     51  1.2  yamt 
     52  1.6    ad 	/* Update start time for this thread. */
     53  1.6    ad 	microtime(&l->l_stime);
     54  1.6    ad 
     55  1.2  yamt 	KERNEL_UNLOCK_ALL(l, NULL);
     56  1.2  yamt 	l->l_usrpri = PIDLELWP;
     57  1.3    ad 	l->l_priority = l->l_usrpri;
     58  1.2  yamt 	l->l_stat = LSONPROC;
     59  1.2  yamt 	while (1 /* CONSTCOND */) {
     60  1.2  yamt 		KERNEL_LOCK_ASSERT_UNLOCKED();
     61  1.2  yamt 		LOCKDEBUG_BARRIER(NULL, 0);
     62  1.2  yamt 		KASSERT((l->l_flag & LW_IDLE) != 0);
     63  1.2  yamt 		KASSERT(ci == curcpu());
     64  1.2  yamt 		KASSERT(l == curlwp);
     65  1.2  yamt 		KASSERT(CURCPU_IDLE_P());
     66  1.2  yamt 		KASSERT(l->l_usrpri == PIDLELWP);
     67  1.2  yamt 
     68  1.2  yamt 		if (uvm.page_idle_zero) {
     69  1.2  yamt 			if (sched_curcpu_runnable_p()) {
     70  1.2  yamt 				goto schedule;
     71  1.2  yamt 			}
     72  1.2  yamt 			uvm_pageidlezero();
     73  1.2  yamt 		}
     74  1.2  yamt 		if (!sched_curcpu_runnable_p()) {
     75  1.2  yamt 			cpu_idle();
     76  1.5    ad 			if (!sched_curcpu_runnable_p() &&
     77  1.5    ad 			    !ci->ci_want_resched) {
     78  1.2  yamt 				continue;
     79  1.2  yamt 			}
     80  1.2  yamt 		}
     81  1.2  yamt schedule:
     82  1.2  yamt 		KASSERT(l->l_mutex == &l->l_cpu->ci_schedstate.spc_lwplock);
     83  1.2  yamt 		lwp_lock(l);
     84  1.2  yamt 		mi_switch(l);
     85  1.2  yamt 		KASSERT(curlwp == l);
     86  1.2  yamt 		KASSERT(l->l_stat == LSONPROC);
     87  1.2  yamt 	}
     88  1.2  yamt }
     89  1.2  yamt 
     90  1.2  yamt int
     91  1.2  yamt create_idle_lwp(struct cpu_info *ci)
     92  1.2  yamt {
     93  1.2  yamt 	struct proc *p = &proc0;
     94  1.2  yamt 	struct lwp *l;
     95  1.2  yamt 	char *name;
     96  1.2  yamt 	vaddr_t uaddr;
     97  1.2  yamt 	bool inmem;
     98  1.2  yamt 	cpuid_t cpuid;
     99  1.2  yamt 	int error;
    100  1.2  yamt 
    101  1.2  yamt 	KASSERT(ci->ci_data.cpu_idlelwp == NULL);
    102  1.2  yamt 	inmem = uvm_uarea_alloc(&uaddr);
    103  1.2  yamt 	if (uaddr == 0) {
    104  1.2  yamt 		return ENOMEM;
    105  1.2  yamt 	}
    106  1.2  yamt 	error = newlwp(&lwp0, p, uaddr, inmem, 0, NULL, 0, idle_loop, NULL, &l);
    107  1.2  yamt 	if (error != 0) {
    108  1.2  yamt 		panic("create_idle_lwp: newlwp failed");
    109  1.2  yamt 	}
    110  1.3    ad 	uvm_lwp_hold(l);
    111  1.2  yamt 	l->l_flag |= (LW_IDLE | LW_BOUND);
    112  1.2  yamt 	l->l_cpu = ci;
    113  1.2  yamt 	l->l_mutex = &ci->ci_schedstate.spc_lwplock;
    114  1.2  yamt 	ci->ci_data.cpu_idlelwp = l;
    115  1.2  yamt 	name = kmem_alloc(MAXCOMLEN, KM_NOSLEEP);
    116  1.2  yamt 	if (name != NULL) {
    117  1.2  yamt #ifdef MULTIPROCESSOR		/* XXX should be mandatory */
    118  1.2  yamt 		cpuid = ci->ci_cpuid;
    119  1.2  yamt #else
    120  1.2  yamt 		cpuid = 0;
    121  1.2  yamt #endif
    122  1.3    ad 		snprintf(name, MAXCOMLEN, "idle/%d", (int)cpuid);
    123  1.2  yamt 		lwp_lock(l);
    124  1.2  yamt 		l->l_name = name;
    125  1.2  yamt 		lwp_unlock(l);
    126  1.2  yamt 	}
    127  1.2  yamt 	return error;
    128  1.2  yamt }
    129