aboutsummaryrefslogtreecommitdiff
path: root/sys/posix4/ksched.c
blob: 90c029ac311bdf3a5c7935071c004a5f63530017 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
/*
 * Copyright (c) 1996, 1997
 *	HD Associates, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by HD Associates, Inc
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

/* ksched: Soft real time scheduling based on "rtprio".
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <machine/cpu.h>	/* For need_resched */

#include <posix4/posix4.h>

/* ksched: Real-time extension to support POSIX priority scheduling.
 */

struct ksched {
	struct timespec rr_interval;
};

int ksched_attach(struct ksched **p)
{
	struct ksched *ksched= p31b_malloc(sizeof(*ksched));

	ksched->rr_interval.tv_sec = 0;
	ksched->rr_interval.tv_nsec = 1000000000L / roundrobin_interval();

	*p = ksched;
	return 0;
}

int ksched_detach(struct ksched *p)
{
	p31b_free(p);

	return 0;
}

/*
 * XXX About priorities
 *
 *	POSIX 1003.1b requires that numerically higher priorities be of
 *	higher priority.  It also permits sched_setparam to be
 *	implementation defined for SCHED_OTHER.  I don't like
 *	the notion of inverted priorites for normal processes when
 *  you can use "setpriority" for that.
 *
 *	I'm rejecting sched_setparam for SCHED_OTHER with EINVAL.
 */

/* Macros to convert between the unix (lower numerically is higher priority)
 * and POSIX 1003.1b (higher numerically is higher priority)
 */

#define p4prio_to_rtpprio(P) (RTP_PRIO_MAX - (P))
#define rtpprio_to_p4prio(P) (RTP_PRIO_MAX - (P))

static inline int
getscheduler(int *ret, struct ksched *ksched, struct proc *p)
{
	int e = 0;

	switch (p->p_rtprio.type)
	{
		case RTP_PRIO_FIFO:
		*ret = SCHED_FIFO;
		break;

		case RTP_PRIO_REALTIME:
		*ret = SCHED_RR;
		break;

		default:
		*ret = SCHED_OTHER;
		break;
	}

	return e;
}

int ksched_setparam(int *ret, struct ksched *ksched,
	struct proc *p, const struct sched_param *param)
{
	int e, policy;

	e = getscheduler(&policy, ksched, p);

	if (e == 0)
	{
		if (policy == SCHED_OTHER)
			e = EINVAL;
		else
			e = ksched_setscheduler(ret, ksched, p, policy, param);
	}

	return e;
}

int ksched_getparam(int *ret, struct ksched *ksched,
	struct proc *p, struct sched_param *param)
{
	if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type))
		param->sched_priority = rtpprio_to_p4prio(p->p_rtprio.prio);

	return 0;
}

/*
 * XXX The priority and scheduler modifications should
 *     be moved into published interfaces in kern/kern_sync.
 *
 * The permissions to modify process p were checked in "p31b_proc()".
 *
 */
int ksched_setscheduler(int *ret, struct ksched *ksched,
	struct proc *p, int policy, const struct sched_param *param)
{
	int e = 0;
	struct rtprio rtp;

	switch(policy)
	{
		case SCHED_RR:
		case SCHED_FIFO:

		if (param->sched_priority >= RTP_PRIO_MIN &&
		param->sched_priority <= RTP_PRIO_MAX)
		{
			rtp.type = (policy == SCHED_FIFO)
				? RTP_PRIO_FIFO : RTP_PRIO_REALTIME;

			rtp.prio = p4prio_to_rtpprio(RTP_PRIO_MAX);
			p->p_rtprio = rtp;
			(void)resetpriority(p);
		}
		else
			e = EPERM;


		break;

		case SCHED_OTHER:
		{
			rtp.type = RTP_PRIO_NORMAL;
			rtp.prio = p4prio_to_rtpprio(RTP_PRIO_MIN);
			p->p_rtprio = rtp;

			/* XXX Simply revert to whatever we had for last
			 *     normal scheduler priorities.
			 *     This puts a requirement
			 *     on the scheduling code: You must leave the
			 *     scheduling info alone.
			 */
			(void)resetpriority(p);
		}
		break;
	}

	return e;
}

int ksched_getscheduler(int *ret, struct ksched *ksched, struct proc *p)
{
	return getscheduler(ret, ksched, p);
}

/* ksched_yield: Yield the CPU.
 */
int ksched_yield(int *ret, struct ksched *ksched)
{
	need_resched();
	return 0;
}

int ksched_get_priority_max(int *ret, struct ksched *ksched, int policy)
{
	int e = 0;

	switch (policy)
	{
		case SCHED_FIFO:
		case SCHED_RR:
		*ret = RTP_PRIO_MAX;
		break;

		case SCHED_OTHER:
		*ret =  PRIO_MAX;
		break;

		default:
		e = EINVAL;
	}

	return e;
}

int ksched_get_priority_min(int *ret, struct ksched *ksched, int policy)
{
	int e = 0;

	switch (policy)
	{
		case SCHED_FIFO:
		case SCHED_RR:
		*ret = RTP_PRIO_MIN;
		break;

		case SCHED_OTHER:
		*ret =  PRIO_MIN;
		break;

		default:
		e = EINVAL;
	}

	return e;
}

int ksched_rr_get_interval(int *ret, struct ksched *ksched,
	struct proc *p, struct timespec *timespec)
{
	*timespec = ksched->rr_interval;

	return 0;
}