1 /* 2 * Copyright (c) 1996, 1997 3 * HD Associates, Inc. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by HD Associates, Inc 16 * 4. Neither the name of the author nor the names of any co-contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD: src/sys/posix4/ksched.c,v 1.7.2.1 2000/05/16 06:58:13 dillon Exp $ 33 */ 34 35 /* 36 * ksched: Soft real time scheduling based on "rtprio". 37 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/posix4.h> 42 #include <sys/proc.h> 43 #include <sys/kernel.h> 44 #include <sys/resource.h> 45 #include <machine/cpu.h> /* For need_user_resched */ 46 47 48 /* ksched: Real-time extension to support POSIX priority scheduling. 49 */ 50 51 struct ksched { 52 struct timespec rr_interval; 53 }; 54 55 int 56 ksched_attach(struct ksched **p) 57 { 58 struct ksched *ksched= p31b_malloc(sizeof(*ksched)); 59 60 ksched->rr_interval.tv_sec = 0; 61 ksched->rr_interval.tv_nsec = 1000000000L / 10; /* XXX */ 62 63 *p = ksched; 64 return 0; 65 } 66 67 int 68 ksched_detach(struct ksched *p) 69 { 70 p31b_free(p); 71 72 return 0; 73 } 74 75 /* 76 * XXX About priorities 77 * 78 * POSIX 1003.1b requires that numerically higher priorities be of 79 * higher priority. It also permits sched_setparam to be 80 * implementation defined for SCHED_OTHER. I don't like 81 * the notion of inverted priorites for normal processes when 82 * you can use "setpriority" for that. 83 * 84 * I'm rejecting sched_setparam for SCHED_OTHER with EINVAL. 85 */ 86 87 /* Macros to convert between the unix (lower numerically is higher priority) 88 * and POSIX 1003.1b (higher numerically is higher priority) 89 */ 90 91 #define p4prio_to_rtpprio(P) (RTP_PRIO_MAX - (P)) 92 #define rtpprio_to_p4prio(P) (RTP_PRIO_MAX - (P)) 93 94 /* 95 * These improve readability a bit for me: 96 */ 97 #define P1B_PRIO_MIN rtpprio_to_p4prio(RTP_PRIO_MAX) 98 #define P1B_PRIO_MAX rtpprio_to_p4prio(RTP_PRIO_MIN) 99 100 static __inline int 101 getscheduler(register_t *ret, struct ksched *ksched, struct lwp *lp) 102 { 103 int e = 0; 104 105 switch (lp->lwp_rtprio.type) { 106 case RTP_PRIO_FIFO: 107 *ret = SCHED_FIFO; 108 break; 109 case RTP_PRIO_REALTIME: 110 *ret = SCHED_RR; 111 break; 112 default: 113 *ret = SCHED_OTHER; 114 break; 115 } 116 117 return e; 118 } 119 120 int 121 ksched_setparam(register_t *ret, struct ksched *ksched, 122 struct lwp *lp, const struct sched_param *param) 123 { 124 register_t policy; 125 int e; 126 127 e = getscheduler(&policy, ksched, lp); 128 129 if (e == 0) { 130 if (policy == SCHED_OTHER) 131 e = EINVAL; 132 else 133 e = ksched_setscheduler(ret, ksched, lp, policy, param); 134 } 135 136 return e; 137 } 138 139 int 140 ksched_getparam(register_t *ret, struct ksched *ksched, 141 struct lwp *lp, struct sched_param *param) 142 { 143 if (RTP_PRIO_IS_REALTIME(lp->lwp_rtprio.type)) 144 param->sched_priority = rtpprio_to_p4prio(lp->lwp_rtprio.prio); 145 146 return 0; 147 } 148 149 /* 150 * XXX The priority and scheduler modifications should 151 * be moved into published interfaces in kern/kern_sync. 152 * 153 * The permissions to modify process p were checked in "p31b_proc()". 154 * 155 */ 156 int 157 ksched_setscheduler(register_t *ret, struct ksched *ksched, 158 struct lwp *lp, int policy, const struct sched_param *param) 159 { 160 int e = 0; 161 struct rtprio rtp; 162 163 switch(policy) { 164 case SCHED_RR: 165 case SCHED_FIFO: 166 if (param->sched_priority >= P1B_PRIO_MIN && 167 param->sched_priority <= P1B_PRIO_MAX) { 168 rtp.prio = p4prio_to_rtpprio(param->sched_priority); 169 rtp.type = (policy == SCHED_FIFO) ? 170 RTP_PRIO_FIFO : RTP_PRIO_REALTIME; 171 172 lp->lwp_rtprio = rtp; 173 need_user_resched(); 174 } else { 175 e = EINVAL; 176 } 177 break; 178 case SCHED_OTHER: 179 rtp.type = RTP_PRIO_NORMAL; 180 rtp.prio = p4prio_to_rtpprio(param->sched_priority); 181 lp->lwp_rtprio = rtp; 182 183 /* 184 * XXX Simply revert to whatever we had for last 185 * normal scheduler priorities. 186 * This puts a requirement 187 * on the scheduling code: You must leave the 188 * scheduling info alone. 189 */ 190 need_user_resched(); 191 break; 192 } 193 194 return e; 195 } 196 197 int 198 ksched_getscheduler(register_t *ret, struct ksched *ksched, struct lwp *lp) 199 { 200 return getscheduler(ret, ksched, lp); 201 } 202 203 /* 204 * ksched_yield: Yield the CPU. 205 * 206 * MPSAFE 207 */ 208 int 209 ksched_yield(register_t *ret, struct ksched *ksched) 210 { 211 struct lwp *lp; 212 213 if ((lp = curthread->td_lwp) != NULL) 214 lp->lwp_proc->p_usched->yield(lp); 215 return 0; 216 } 217 218 /* 219 * MPSAFE 220 */ 221 int 222 ksched_get_priority_max(register_t*ret, struct ksched *ksched, int policy) 223 { 224 int e = 0; 225 226 switch (policy) { 227 case SCHED_FIFO: 228 case SCHED_RR: 229 *ret = RTP_PRIO_MAX; 230 break; 231 case SCHED_OTHER: 232 *ret = PRIO_MAX; 233 break; 234 default: 235 e = EINVAL; 236 break; 237 } 238 239 return e; 240 } 241 242 /* 243 * MPSAFE 244 */ 245 int 246 ksched_get_priority_min(register_t *ret, struct ksched *ksched, int policy) 247 { 248 int e = 0; 249 250 switch (policy) { 251 case SCHED_FIFO: 252 case SCHED_RR: 253 *ret = P1B_PRIO_MIN; 254 break; 255 case SCHED_OTHER: 256 *ret = PRIO_MIN; 257 break; 258 default: 259 e = EINVAL; 260 break; 261 } 262 return e; 263 } 264 265 /* 266 * MPSAFE 267 */ 268 int 269 ksched_rr_get_interval(register_t *ret, struct ksched *ksched, 270 struct lwp *lp, struct timespec *timespec) 271 { 272 *timespec = ksched->rr_interval; 273 274 return 0; 275 } 276