1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (c) 1996, 1997
5 * HD Associates, Inc. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by HD Associates, Inc
18 * 4. Neither the name of the author nor the names of any co-contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 /* ksched: Soft real time scheduling based on "rtprio". */
36
37 #include <sys/cdefs.h>
38 #include "opt_posix.h"
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/lock.h>
43 #include <sys/sysctl.h>
44 #include <sys/kernel.h>
45 #include <sys/mutex.h>
46 #include <sys/proc.h>
47 #include <sys/posix4.h>
48 #include <sys/resource.h>
49 #include <sys/sched.h>
50
51 FEATURE(kposix_priority_scheduling, "POSIX P1003.1B realtime extensions");
52
53 /* ksched: Real-time extension to support POSIX priority scheduling. */
54
55 struct ksched {
56 struct timespec rr_interval;
57 };
58
59 int
ksched_attach(struct ksched ** p)60 ksched_attach(struct ksched **p)
61 {
62 struct ksched *ksched;
63
64 ksched = malloc(sizeof(*ksched), M_P31B, M_WAITOK);
65 ksched->rr_interval.tv_sec = 0;
66 ksched->rr_interval.tv_nsec = 1000000000L / hz * sched_rr_interval();
67 *p = ksched;
68 return (0);
69 }
70
71 int
ksched_detach(struct ksched * ks)72 ksched_detach(struct ksched *ks)
73 {
74
75 free(ks, M_P31B);
76 return (0);
77 }
78
79 /*
80 * XXX About priorities
81 *
82 * POSIX 1003.1b requires that numerically higher priorities be of
83 * higher priority. It also permits sched_setparam to be
84 * implementation defined for SCHED_OTHER. I don't like
85 * the notion of inverted priorites for normal processes when
86 * you can use "setpriority" for that.
87 *
88 */
89
90 /* Macros to convert between the unix (lower numerically is higher priority)
91 * and POSIX 1003.1b (higher numerically is higher priority)
92 */
93
94 #define p4prio_to_rtpprio(P) (RTP_PRIO_MAX - (P))
95 #define rtpprio_to_p4prio(P) (RTP_PRIO_MAX - (P))
96
97 #define p4prio_to_tsprio(P) ((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) - (P))
98 #define tsprio_to_p4prio(P) ((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) - (P))
99
100 /* These improve readability a bit for me:
101 */
102 #define P1B_PRIO_MIN rtpprio_to_p4prio(RTP_PRIO_MAX)
103 #define P1B_PRIO_MAX rtpprio_to_p4prio(RTP_PRIO_MIN)
104
105 static __inline int
getscheduler(struct ksched * ksched,struct thread * td,int * policy)106 getscheduler(struct ksched *ksched, struct thread *td, int *policy)
107 {
108 struct rtprio rtp;
109 int e;
110
111 e = 0;
112 pri_to_rtp(td, &rtp);
113 switch (rtp.type) {
114 case RTP_PRIO_FIFO:
115 *policy = SCHED_FIFO;
116 break;
117 case RTP_PRIO_REALTIME:
118 *policy = SCHED_RR;
119 break;
120 default:
121 *policy = SCHED_OTHER;
122 break;
123 }
124 return (e);
125 }
126
127 int
ksched_setparam(struct ksched * ksched,struct thread * td,const struct sched_param * param)128 ksched_setparam(struct ksched *ksched,
129 struct thread *td, const struct sched_param *param)
130 {
131 int e, policy;
132
133 e = getscheduler(ksched, td, &policy);
134 if (e == 0)
135 e = ksched_setscheduler(ksched, td, policy, param);
136 return (e);
137 }
138
139 int
ksched_getparam(struct ksched * ksched,struct thread * td,struct sched_param * param)140 ksched_getparam(struct ksched *ksched, struct thread *td,
141 struct sched_param *param)
142 {
143 struct rtprio rtp;
144
145 pri_to_rtp(td, &rtp);
146 if (RTP_PRIO_IS_REALTIME(rtp.type))
147 param->sched_priority = rtpprio_to_p4prio(rtp.prio);
148 else {
149 if (PRI_MIN_TIMESHARE < rtp.prio)
150 /*
151 * The interactive score has it to min realtime
152 * so we must show max (64 most likely).
153 */
154 param->sched_priority = PRI_MAX_TIMESHARE -
155 PRI_MIN_TIMESHARE;
156 else
157 param->sched_priority = tsprio_to_p4prio(rtp.prio);
158 }
159 return (0);
160 }
161
162 /*
163 * XXX The priority and scheduler modifications should
164 * be moved into published interfaces in kern/kern_sync.
165 *
166 * The permissions to modify process p were checked in "p31b_proc()".
167 *
168 */
169 int
ksched_setscheduler(struct ksched * ksched,struct thread * td,int policy,const struct sched_param * param)170 ksched_setscheduler(struct ksched *ksched, struct thread *td, int policy,
171 const struct sched_param *param)
172 {
173 struct rtprio rtp;
174 int e;
175
176 e = 0;
177 switch(policy) {
178 case SCHED_RR:
179 case SCHED_FIFO:
180 if (param->sched_priority >= P1B_PRIO_MIN &&
181 param->sched_priority <= P1B_PRIO_MAX) {
182 rtp.prio = p4prio_to_rtpprio(param->sched_priority);
183 rtp.type = (policy == SCHED_FIFO) ? RTP_PRIO_FIFO :
184 RTP_PRIO_REALTIME;
185 rtp_to_pri(&rtp, td);
186 } else {
187 e = EINVAL;
188 }
189 break;
190 case SCHED_OTHER:
191 if (param->sched_priority >= 0 && param->sched_priority <=
192 (PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE)) {
193 rtp.type = RTP_PRIO_NORMAL;
194 rtp.prio = p4prio_to_tsprio(param->sched_priority);
195 rtp_to_pri(&rtp, td);
196 } else {
197 e = EINVAL;
198 }
199 break;
200 default:
201 e = EINVAL;
202 break;
203 }
204 return (e);
205 }
206
207 int
ksched_getscheduler(struct ksched * ksched,struct thread * td,int * policy)208 ksched_getscheduler(struct ksched *ksched, struct thread *td, int *policy)
209 {
210
211 return (getscheduler(ksched, td, policy));
212 }
213
214 /* ksched_yield: Yield the CPU. */
215 int
ksched_yield(struct ksched * ksched)216 ksched_yield(struct ksched *ksched)
217 {
218
219 sched_relinquish(curthread);
220 return (0);
221 }
222
223 int
ksched_get_priority_max(struct ksched * ksched,int policy,int * prio)224 ksched_get_priority_max(struct ksched *ksched, int policy, int *prio)
225 {
226 int e;
227
228 e = 0;
229 switch (policy) {
230 case SCHED_FIFO:
231 case SCHED_RR:
232 *prio = P1B_PRIO_MAX;
233 break;
234 case SCHED_OTHER:
235 *prio = PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE;
236 break;
237 default:
238 e = EINVAL;
239 break;
240 }
241 return (e);
242 }
243
244 int
ksched_get_priority_min(struct ksched * ksched,int policy,int * prio)245 ksched_get_priority_min(struct ksched *ksched, int policy, int *prio)
246 {
247 int e;
248
249 e = 0;
250 switch (policy) {
251 case SCHED_FIFO:
252 case SCHED_RR:
253 *prio = P1B_PRIO_MIN;
254 break;
255 case SCHED_OTHER:
256 *prio = 0;
257 break;
258 default:
259 e = EINVAL;
260 break;
261 }
262 return (e);
263 }
264
265 int
ksched_rr_get_interval(struct ksched * ksched,struct thread * td,struct timespec * timespec)266 ksched_rr_get_interval(struct ksched *ksched, struct thread *td,
267 struct timespec *timespec)
268 {
269
270 *timespec = ksched->rr_interval;
271 return (0);
272 }
273