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/malloc.h>
42 #include <sys/posix4.h>
43 #include <sys/proc.h>
44 #include <sys/kernel.h>
45 #include <sys/resource.h>
46 #include <machine/cpu.h> /* For need_user_resched */
47
48
49 /* ksched: Real-time extension to support POSIX priority scheduling.
50 */
51
52 struct ksched {
53 struct timespec rr_interval;
54 };
55
56 int
ksched_attach(struct ksched ** p)57 ksched_attach(struct ksched **p)
58 {
59 struct ksched *ksched;
60
61 ksched = kmalloc(sizeof(*ksched), M_P31B, M_WAITOK);
62
63 ksched->rr_interval.tv_sec = 0;
64 ksched->rr_interval.tv_nsec = 1000000000L / 10; /* XXX */
65
66 *p = ksched;
67 return 0;
68 }
69
70 int
ksched_detach(struct ksched * p)71 ksched_detach(struct ksched *p)
72 {
73 kfree(p, M_P31B);
74
75 return 0;
76 }
77
78 /*
79 * XXX About priorities
80 *
81 * POSIX 1003.1b requires that numerically higher priorities be of
82 * higher priority. It also permits sched_setparam to be
83 * implementation defined for SCHED_OTHER. I don't like
84 * the notion of inverted priorites for normal processes when
85 * you can use "setpriority" for that.
86 *
87 * I'm rejecting sched_setparam for SCHED_OTHER with EINVAL.
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 /*
98 * These improve readability a bit for me:
99 */
100 #define P1B_PRIO_MIN rtpprio_to_p4prio(RTP_PRIO_MAX)
101 #define P1B_PRIO_MAX rtpprio_to_p4prio(RTP_PRIO_MIN)
102
103 static __inline int
getscheduler(register_t * ret,struct ksched * ksched,struct lwp * lp)104 getscheduler(register_t *ret, struct ksched *ksched, struct lwp *lp)
105 {
106 int e = 0;
107
108 switch (lp->lwp_rtprio.type) {
109 case RTP_PRIO_FIFO:
110 *ret = SCHED_FIFO;
111 break;
112 case RTP_PRIO_REALTIME:
113 *ret = SCHED_RR;
114 break;
115 default:
116 *ret = SCHED_OTHER;
117 break;
118 }
119
120 return e;
121 }
122
123 int
ksched_setparam(register_t * ret,struct ksched * ksched,struct lwp * lp,const struct sched_param * param)124 ksched_setparam(register_t *ret, struct ksched *ksched,
125 struct lwp *lp, const struct sched_param *param)
126 {
127 register_t policy;
128 int e;
129
130 e = getscheduler(&policy, ksched, lp);
131
132 if (e == 0) {
133 if (policy == SCHED_OTHER)
134 e = EINVAL;
135 else
136 e = ksched_setscheduler(ret, ksched, lp, policy, param);
137 }
138
139 return e;
140 }
141
142 int
ksched_getparam(register_t * ret,struct ksched * ksched,struct lwp * lp,struct sched_param * param)143 ksched_getparam(register_t *ret, struct ksched *ksched,
144 struct lwp *lp, struct sched_param *param)
145 {
146 if (RTP_PRIO_IS_REALTIME(lp->lwp_rtprio.type))
147 param->sched_priority = rtpprio_to_p4prio(lp->lwp_rtprio.prio);
148
149 return 0;
150 }
151
152 /*
153 * XXX The priority and scheduler modifications should
154 * be moved into published interfaces in kern/kern_sync.
155 *
156 * The permissions to modify process p were checked in "p31b_proc()".
157 *
158 */
159 int
ksched_setscheduler(register_t * ret,struct ksched * ksched,struct lwp * lp,int policy,const struct sched_param * param)160 ksched_setscheduler(register_t *ret, struct ksched *ksched,
161 struct lwp *lp, int policy, const struct sched_param *param)
162 {
163 int e = 0;
164 struct rtprio rtp;
165
166 switch(policy) {
167 case SCHED_RR:
168 case SCHED_FIFO:
169 if (param->sched_priority >= P1B_PRIO_MIN &&
170 param->sched_priority <= P1B_PRIO_MAX) {
171 rtp.prio = p4prio_to_rtpprio(param->sched_priority);
172 rtp.type = (policy == SCHED_FIFO) ?
173 RTP_PRIO_FIFO : RTP_PRIO_REALTIME;
174
175 lp->lwp_rtprio = rtp;
176 need_user_resched();
177 } else {
178 e = EINVAL;
179 }
180 break;
181 case SCHED_OTHER:
182 rtp.type = RTP_PRIO_NORMAL;
183 rtp.prio = p4prio_to_rtpprio(param->sched_priority);
184 lp->lwp_rtprio = rtp;
185
186 /*
187 * XXX Simply revert to whatever we had for last
188 * normal scheduler priorities.
189 * This puts a requirement
190 * on the scheduling code: You must leave the
191 * scheduling info alone.
192 */
193 need_user_resched();
194 break;
195 }
196
197 return e;
198 }
199
200 int
ksched_getscheduler(register_t * ret,struct ksched * ksched,struct lwp * lp)201 ksched_getscheduler(register_t *ret, struct ksched *ksched, struct lwp *lp)
202 {
203 return getscheduler(ret, ksched, lp);
204 }
205
206 /*
207 * ksched_yield: Yield the CPU.
208 *
209 * MPSAFE
210 */
211 int
ksched_yield(register_t * ret,struct ksched * ksched)212 ksched_yield(register_t *ret, struct ksched *ksched)
213 {
214 struct lwp *lp;
215
216 if ((lp = curthread->td_lwp) != NULL)
217 lp->lwp_proc->p_usched->yield(lp);
218 return 0;
219 }
220
221 /*
222 * MPSAFE
223 */
224 int
ksched_get_priority_max(register_t * ret,struct ksched * ksched,int policy)225 ksched_get_priority_max(register_t*ret, struct ksched *ksched, int policy)
226 {
227 int e = 0;
228
229 switch (policy) {
230 case SCHED_FIFO:
231 case SCHED_RR:
232 *ret = RTP_PRIO_MAX;
233 break;
234 case SCHED_OTHER:
235 *ret = PRIO_MAX;
236 break;
237 default:
238 e = EINVAL;
239 break;
240 }
241
242 return e;
243 }
244
245 /*
246 * MPSAFE
247 */
248 int
ksched_get_priority_min(register_t * ret,struct ksched * ksched,int policy)249 ksched_get_priority_min(register_t *ret, struct ksched *ksched, int policy)
250 {
251 int e = 0;
252
253 switch (policy) {
254 case SCHED_FIFO:
255 case SCHED_RR:
256 *ret = P1B_PRIO_MIN;
257 break;
258 case SCHED_OTHER:
259 *ret = PRIO_MIN;
260 break;
261 default:
262 e = EINVAL;
263 break;
264 }
265 return e;
266 }
267
268 /*
269 * MPSAFE
270 */
271 int
ksched_rr_get_interval(register_t * ret,struct ksched * ksched,struct lwp * lp,struct timespec * timespec)272 ksched_rr_get_interval(register_t *ret, struct ksched *ksched,
273 struct lwp *lp, struct timespec *timespec)
274 {
275 *timespec = ksched->rr_interval;
276
277 return 0;
278 }
279