1 /* $NetBSD: sleepq.c,v 1.28 2023/10/13 18:23:54 ad 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 1.28 2023/10/13 18:23:54 ad 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 #include <sys/atomic.h> 39 40 #include <rump-sys/kern.h> 41 42 syncobj_t sleep_syncobj; 43 44 void 45 sleepq_init(sleepq_t *sq) 46 { 47 48 LIST_INIT(sq); 49 cv_init(&sq->sq_cv, "sleepq"); 50 } 51 52 void 53 sleepq_destroy(sleepq_t *sq) 54 { 55 56 cv_destroy(&sq->sq_cv); 57 } 58 59 int 60 sleepq_enter(sleepq_t *sq, lwp_t *l, kmutex_t *mp) 61 { 62 int nlocks; 63 64 lwp_lock(l); 65 if (mp != NULL) { 66 lwp_unlock_to(l, mp); 67 } 68 if ((nlocks = l->l_blcnt) != 0) { 69 KERNEL_UNLOCK_ALL(NULL, NULL); 70 } 71 return nlocks; 72 } 73 74 void 75 sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob, 76 bool catch_p) 77 { 78 struct lwp *l = curlwp; 79 80 l->l_wchan = wc; 81 l->l_wmesg = wmsg; 82 l->l_sleepq = sq; 83 LIST_INSERT_HEAD(sq, l, l_sleepchain); 84 } 85 86 int 87 sleepq_block(int timo, bool catch, syncobj_t *syncobj __unused, int nlocks) 88 { 89 struct lwp *l = curlwp; 90 int error = 0; 91 kmutex_t *mp = l->l_mutex; 92 93 while (l->l_wchan) { 94 l->l_mutex = mp; /* keep sleepq lock until woken up */ 95 error = cv_timedwait(&l->l_sleepq->sq_cv, mp, timo); 96 if (error == EWOULDBLOCK || error == EINTR) { 97 if (l->l_wchan) { 98 LIST_REMOVE(l, l_sleepchain); 99 l->l_wchan = NULL; 100 l->l_wmesg = NULL; 101 } 102 } 103 } 104 mutex_spin_exit(mp); 105 106 if (nlocks) 107 KERNEL_LOCK(nlocks, curlwp); 108 109 return error; 110 } 111 112 void 113 sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp) 114 { 115 struct lwp *l, *l_next; 116 bool found = false; 117 118 for (l = LIST_FIRST(sq); l; l = l_next) { 119 l_next = LIST_NEXT(l, l_sleepchain); 120 if (l->l_wchan == wchan) { 121 found = true; 122 l->l_wchan = NULL; 123 l->l_wmesg = NULL; 124 LIST_REMOVE(l, l_sleepchain); 125 if (--expected == 0) 126 break; 127 } 128 } 129 if (found) 130 cv_broadcast(&sq->sq_cv); 131 132 mutex_spin_exit(mp); 133 } 134 135 void 136 sleepq_unsleep(struct lwp *l, bool cleanup) 137 { 138 139 l->l_wchan = NULL; 140 l->l_wmesg = NULL; 141 LIST_REMOVE(l, l_sleepchain); 142 cv_broadcast(&l->l_sleepq->sq_cv); 143 144 if (cleanup) { 145 mutex_spin_exit(l->l_mutex); 146 } 147 } 148 149 void 150 sleepq_remove(sleepq_t *sq, struct lwp *l, bool wakeup) 151 { 152 153 sleepq_unsleep(l, false); 154 } 155 156 /* 157 * Thread scheduler handles priorities. Therefore no action here. 158 * (maybe do something if we're deperate?) 159 */ 160 void 161 sleepq_changepri(struct lwp *l, pri_t pri) 162 { 163 164 } 165 166 void 167 sleepq_lendpri(struct lwp *l, pri_t pri) 168 { 169 170 } 171 172 struct lwp * 173 syncobj_noowner(wchan_t wc) 174 { 175 176 return NULL; 177 } 178 179 void 180 lwp_unlock_to(struct lwp *l, kmutex_t *new) 181 { 182 kmutex_t *old; 183 184 KASSERT(mutex_owned(l->l_mutex)); 185 186 old = l->l_mutex; 187 atomic_store_release(&l->l_mutex, new); 188 mutex_spin_exit(old); 189 } 190 191 void 192 lwp_lock(lwp_t *l) 193 { 194 kmutex_t *old = atomic_load_consume(&l->l_mutex); 195 196 mutex_spin_enter(old); 197 while (__predict_false(atomic_load_relaxed(&l->l_mutex) != old)) { 198 mutex_spin_exit(old); 199 old = atomic_load_consume(&l->l_mutex); 200 mutex_spin_enter(old); 201 } 202 } 203 204 void 205 lwp_unlock(lwp_t *l) 206 { 207 208 mutex_spin_exit(l->l_mutex); 209 } 210 211 void 212 lwp_changepri(lwp_t *l, pri_t pri) 213 { 214 215 /* fuck */ 216 } 217 218 void 219 lwp_lendpri(lwp_t *l, pri_t pri) 220 { 221 222 /* you */ 223 } 224 225 pri_t 226 lwp_eprio(lwp_t *l) 227 { 228 229 /* Antti */ 230 return l->l_priority; 231 } 232