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scheduler.c revision 1.2 
      1 /*      $NetBSD: scheduler.c,v 1.2 2009/10/15 16:39:22 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
      5  *
      6  * Development of this software was supported by
      7  * The Finnish Cultural Foundation.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     19  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     21  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 #include <sys/cdefs.h>
     32 __KERNEL_RCSID(0, "$NetBSD: scheduler.c,v 1.2 2009/10/15 16:39:22 pooka Exp $");
     33 
     34 #include <sys/param.h>
     35 #include <sys/cpu.h>
     36 #include <sys/kmem.h>
     37 #include <sys/mutex.h>
     38 #include <sys/queue.h>
     39 #include <sys/select.h>
     40 
     41 #include <rump/rumpuser.h>
     42 
     43 #include "rump_private.h"
     44 
     45 /* should go for MAXCPUS at some point */
     46 static struct cpu_info rump_cpus[1];
     47 static struct rumpcpu {
     48 	struct cpu_info *rcpu_ci;
     49 	SLIST_ENTRY(rumpcpu) rcpu_entries;
     50 } rcpu_storage[1];
     51 struct cpu_info *rump_cpu = &rump_cpus[0];
     52 int ncpu = 1;
     53 
     54 static SLIST_HEAD(,rumpcpu) cpu_freelist = SLIST_HEAD_INITIALIZER(cpu_freelist);
     55 static struct rumpuser_mtx *schedmtx;
     56 static struct rumpuser_cv *schedcv;
     57 
     58 struct cpu_info *
     59 cpu_lookup(u_int index)
     60 {
     61 
     62 	return &rump_cpus[index];
     63 }
     64 
     65 void
     66 rump_scheduler_init()
     67 {
     68 	struct rumpcpu *rcpu;
     69 	struct cpu_info *ci;
     70 	int i;
     71 
     72 	rumpuser_mutex_init(&schedmtx);
     73 	rumpuser_cv_init(&schedcv);
     74 	for (i = 0; i < ncpu; i++) {
     75 		rcpu = &rcpu_storage[i];
     76 		ci = &rump_cpus[i];
     77 		rump_cpu_bootstrap(ci);
     78 		rcpu->rcpu_ci = ci;
     79 		SLIST_INSERT_HEAD(&cpu_freelist, rcpu, rcpu_entries);
     80 	}
     81 }
     82 
     83 void
     84 rump_schedule()
     85 {
     86 	struct lwp *l = rumpuser_get_curlwp();
     87 
     88 	/*
     89 	 * If there is no dedicated lwp, allocate a temp one and
     90 	 * set it to be free'd upon unschedule().
     91 	 */
     92 	if (l == NULL) {
     93 		l = rump_lwp_alloc(0, rump_nextlid());
     94 		rumpuser_set_curlwp(l);
     95 		rump_lwp_release(l);
     96 	}
     97 	rump_schedule_cpu(l);
     98 }
     99 
    100 void
    101 rump_schedule_cpu(struct lwp *l)
    102 {
    103 	struct rumpcpu *rcpu;
    104 
    105 	KASSERT(l->l_cpu == NULL);
    106 	rumpuser_mutex_enter_nowrap(schedmtx);
    107 	while ((rcpu = SLIST_FIRST(&cpu_freelist)) == NULL)
    108 		rumpuser_cv_wait_nowrap(schedcv, schedmtx);
    109 	SLIST_REMOVE_HEAD(&cpu_freelist, rcpu_entries);
    110 	rumpuser_mutex_exit(schedmtx);
    111 	l->l_cpu = rcpu->rcpu_ci;
    112 }
    113 
    114 void
    115 rump_unschedule()
    116 {
    117 	struct lwp *l;
    118 
    119 	l = rumpuser_get_curlwp();
    120 	rump_unschedule_cpu(l);
    121 	if (l->l_flag & LW_WEXIT) {
    122 		kmem_free(l, sizeof(*l));
    123 		rumpuser_set_curlwp(NULL);
    124 	}
    125 }
    126 
    127 void
    128 rump_unschedule_cpu(struct lwp *l)
    129 {
    130 	struct rumpcpu *rcpu;
    131 	struct cpu_info *ci;
    132 
    133 	ci = l->l_cpu;
    134 	l->l_cpu = NULL;
    135 	rcpu = &rcpu_storage[ci-&rump_cpus[0]];
    136 	KASSERT(rcpu->rcpu_ci == ci);
    137 
    138 	rumpuser_mutex_enter_nowrap(schedmtx);
    139 	SLIST_INSERT_HEAD(&cpu_freelist, rcpu, rcpu_entries);
    140 	rumpuser_cv_signal(schedcv);
    141 	rumpuser_mutex_exit(schedmtx);
    142 }
    143