FreeBSD/Linux Kernel Cross Reference
sys/sys/priority.h
1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (c) 1994, Henrik Vestergaard Draboel
5 * 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 Henrik Vestergaard Draboel.
18 * 4. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD$
34 */
35
36 #ifndef _SYS_PRIORITY_H_
37 #define _SYS_PRIORITY_H_
38
39 /*
40 * Process priority specifications.
41 */
42
43 /*
44 * Priority classes.
45 */
46
47 #define PRI_ITHD 1 /* Interrupt thread. */
48 #define PRI_REALTIME 2 /* Real time process. */
49 #define PRI_TIMESHARE 3 /* Time sharing process. */
50 #define PRI_IDLE 4 /* Idle process. */
51
52 /*
53 * PRI_FIFO is POSIX.1B SCHED_FIFO.
54 */
55
56 #define PRI_FIFO_BIT 8
57 #define PRI_FIFO (PRI_FIFO_BIT | PRI_REALTIME)
58
59 #define PRI_BASE(P) ((P) & ~PRI_FIFO_BIT)
60 #define PRI_IS_REALTIME(P) (PRI_BASE(P) == PRI_REALTIME)
61 #define PRI_NEED_RR(P) ((P) != PRI_FIFO)
62
63 /*
64 * Priorities. Note that with 64 run queues, differences less than 4 are
65 * insignificant.
66 */
67
68 /*
69 * Priorities range from 0 to 255, but differences of less then 4 (RQ_PPQ)
70 * are insignificant. Ranges are as follows:
71 *
72 * Interrupt threads: 0 - 15
73 * Realtime user threads: 16 - 47
74 * Top half kernel threads: 48 - 87
75 * Time sharing user threads: 88 - 223
76 * Idle user threads: 224 - 255
77 *
78 * XXX If/When the specific interrupt thread and top half thread ranges
79 * disappear, a larger range can be used for user processes.
80 */
81
82 #define PRI_MIN (0) /* Highest priority. */
83 #define PRI_MAX (255) /* Lowest priority. */
84
85 #define PRI_MIN_ITHD (PRI_MIN)
86 #define PRI_MAX_ITHD (PRI_MIN_REALTIME - 1)
87
88 /*
89 * Most hardware interrupt threads run at the same priority, but can
90 * decay to lower priorities if they run for full time slices.
91 */
92 #define PI_REALTIME (PRI_MIN_ITHD + 0)
93 #define PI_INTR (PRI_MIN_ITHD + 4)
94 #define PI_AV PI_INTR
95 #define PI_NET PI_INTR
96 #define PI_DISK PI_INTR
97 #define PI_TTY PI_INTR
98 #define PI_DULL PI_INTR
99 #define PI_SOFT (PRI_MIN_ITHD + 8)
100 #define PI_SOFTCLOCK PI_SOFT
101 #define PI_SWI(x) PI_SOFT
102
103 #define PRI_MIN_REALTIME (16)
104 #define PRI_MAX_REALTIME (PRI_MIN_KERN - 1)
105
106 #define PRI_MIN_KERN (48)
107 #define PRI_MAX_KERN (PRI_MIN_TIMESHARE - 1)
108
109 #define PSWP (PRI_MIN_KERN + 0)
110 #define PVM (PRI_MIN_KERN + 4)
111 #define PINOD (PRI_MIN_KERN + 8)
112 #define PRIBIO (PRI_MIN_KERN + 12)
113 #define PVFS (PRI_MIN_KERN + 16)
114 #define PZERO (PRI_MIN_KERN + 20)
115 #define PSOCK (PRI_MIN_KERN + 24)
116 #define PWAIT (PRI_MIN_KERN + 28)
117 #define PLOCK (PRI_MIN_KERN + 32)
118 #define PPAUSE (PRI_MIN_KERN + 36)
119
120 #define PRI_MIN_TIMESHARE (88)
121 #define PRI_MAX_TIMESHARE (PRI_MIN_IDLE - 1)
122
123 #define PUSER (PRI_MIN_TIMESHARE)
124
125 #define PRI_MIN_IDLE (224)
126 #define PRI_MAX_IDLE (PRI_MAX)
127
128 #ifdef _KERNEL
129 /* Other arguments for kern_yield(9). */
130 #define PRI_USER -2 /* Change to current user priority. */
131 #define PRI_UNCHANGED -1 /* Do not change priority. */
132 #endif
133
134 struct priority {
135 u_char pri_class; /* Scheduling class. */
136 u_char pri_level; /* Normal priority level. */
137 u_char pri_native; /* Priority before propagation. */
138 u_char pri_user; /* User priority based on p_cpu and p_nice. */
139 };
140
141 #endif /* !_SYS_PRIORITY_H_ */
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