sys/rump/librump/rumpkern/sleepq.c

   1 /*      $NetBSD: sleepq.c,v 1.5 2009/10/21 23:13:53 rmind Exp $ */
   2
   3 /*
   4  * Copyright (c) 2008 Antti Kantee.  All Rights Reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  16  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  18  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  21  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __KERNEL_RCSID(0, "$NetBSD: sleepq.c,v 1.5 2009/10/21 23:13:53 rmind Exp $");
  30
  31 #include <sys/param.h>
  32 #include <sys/condvar.h>
  33 #include <sys/mutex.h>
  34 #include <sys/once.h>
  35 #include <sys/queue.h>
  36 #include <sys/sleepq.h>
  37 #include <sys/syncobj.h>
  38
  39 #include "rump_private.h"
  40
  41 /*
  42  * Flimsy and minimalistic sleepq implementation.  This is implemented
  43  * only for the use of callouts in kern_timeout.c.  locking etc is
  44  * completely incorrect, horrible, etc etc etc.
  45  */
  46
  47 syncobj_t sleep_syncobj;
  48 static kcondvar_t sq_cv;
  49
  50 static int
  51 sqinit1(void)
  52 {
  53
  54         cv_init(&sq_cv, "sleepq");
  55
  56         return 0;
  57 }
  58
  59 void
  60 sleepq_init(sleepq_t *sq)
  61 {
  62         ONCE_DECL(sqctl);
  63
  64         RUN_ONCE(&sqctl, sqinit1);
  65
  66         TAILQ_INIT(sq);
  67 }
  68
  69 void
  70 sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob)
  71 {
  72         struct lwp *l = curlwp;
  73
  74         l->l_wchan = wc;
  75         l->l_sleepq = sq;
  76         TAILQ_INSERT_TAIL(sq, l, l_sleepchain);
  77 }
  78
  79 int
  80 sleepq_block(int timo, bool catch)
  81 {
  82         struct lwp *l = curlwp;
  83         int error = 0;
  84         kmutex_t *mp = l->l_mutex;
  85         int biglocks = l->l_biglocks;
  86
  87         while (l->l_wchan) {
  88                 if ((error=cv_timedwait(&sq_cv, mp, timo)) == EWOULDBLOCK) {
  89                         TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain);
  90                         l->l_wchan = NULL;
  91                 }
  92         }
  93         mutex_spin_exit(mp);
  94
  95         if (biglocks)
  96                 KERNEL_LOCK(biglocks, curlwp);
  97
  98         return error;
  99 }
 100
 101 lwp_t *
 102 sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp)
 103 {
 104         struct lwp *l, *l_next;
 105         bool found = false;
 106
 107         if (__predict_false(expected != -1))
 108                 panic("sleepq_wake: \"expected\" not supported");
 109
 110         for (l = TAILQ_FIRST(sq); l; l = l_next) {
 111                 l_next = TAILQ_NEXT(l, l_sleepchain);
 112                 if (l->l_wchan == wchan) {
 113                         found = true;
 114                         l->l_wchan = NULL;
 115                         TAILQ_REMOVE(sq, l, l_sleepchain);
 116                 }
 117         }
 118         if (found)
 119                 cv_broadcast(&sq_cv);
 120
 121         mutex_spin_exit(mp);
 122         return NULL;
 123 }
 124
 125 void
 126 sleepq_unsleep(struct lwp *l, bool cleanup)
 127 {
 128
 129         l->l_wchan = NULL;
 130         TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain);
 131         cv_broadcast(&sq_cv);
 132
 133         if (cleanup) {
 134                 mutex_spin_exit(l->l_mutex);
 135         }
 136 }
 137
 138 /*
 139  * Thread scheduler handles priorities.  Therefore no action here.
 140  * (maybe do something if we're deperate?)
 141  */
 142 void
 143 sleepq_changepri(struct lwp *l, pri_t pri)
 144 {
 145
 146 }
 147
 148 void
 149 sleepq_lendpri(struct lwp *l, pri_t pri)
 150 {
 151
 152 }
 153
 154 struct lwp *
 155 syncobj_noowner(wchan_t wc)
 156 {
 157
 158         return NULL;
 159 }
 160
 161 /*
 162  * XXX: used only by callout, therefore here.  should try to use
 163  * one in kern_lwp directly.
 164  */
 165 kmutex_t *
 166 lwp_lock_retry(struct lwp *l, kmutex_t *old)
 167 {
 168
 169         while (l->l_mutex != old) {
 170                 mutex_spin_exit(old);
 171                 old = l->l_mutex;
 172                 mutex_spin_enter(old);
 173         }
 174         return old;
 175 }