![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to lock.h CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Net/2] / Net2 / vm|
Return to lock.h CVS log | Up to [Net/2] / Net2 / vm |
1.1 root 1: /*
2: * Copyright (c) 1991 Regents of the University of California.
3: * All rights reserved.
4: *
5: * This code is derived from software contributed to Berkeley by
6: * The Mach Operating System project at Carnegie-Mellon University.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by the University of
19: * California, Berkeley and its contributors.
20: * 4. Neither the name of the University nor the names of its contributors
21: * may be used to endorse or promote products derived from this software
22: * without specific prior written permission.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34: * SUCH DAMAGE.
35: *
1.1.1.2 ! root 36: * from: @(#)lock.h 7.3 (Berkeley) 4/21/91
! 37: * lock.h,v 1.3 1993/05/20 03:59:12 cgd Exp
1.1 root 38: *
39: *
40: * Copyright (c) 1987, 1990 Carnegie-Mellon University.
41: * All rights reserved.
42: *
43: * Authors: Avadis Tevanian, Jr., Michael Wayne Young
44: *
45: * Permission to use, copy, modify and distribute this software and
46: * its documentation is hereby granted, provided that both the copyright
47: * notice and this permission notice appear in all copies of the
48: * software, derivative works or modified versions, and any portions
49: * thereof, and that both notices appear in supporting documentation.
50: *
51: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
52: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
53: * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
54: *
55: * Carnegie Mellon requests users of this software to return to
56: *
57: * Software Distribution Coordinator or [email protected]
58: * School of Computer Science
59: * Carnegie Mellon University
60: * Pittsburgh PA 15213-3890
61: *
62: * any improvements or extensions that they make and grant Carnegie the
63: * rights to redistribute these changes.
64: */
65:
1.1.1.2 ! root 66: #ifndef _VM_LOCK_H_
! 67: #define _VM_LOCK_H_
! 68:
1.1 root 69: /*
70: * Locking primitives definitions
71: */
72:
73: #define NCPUS 1 /* XXX */
74:
75: /*
76: * A simple spin lock.
77: */
78:
79: struct slock {
80: int lock_data; /* in general 1 bit is sufficient */
81: };
82:
83: typedef struct slock simple_lock_data_t;
84: typedef struct slock *simple_lock_t;
85:
86: /*
87: * The general lock structure. Provides for multiple readers,
88: * upgrading from read to write, and sleeping until the lock
89: * can be gained.
90: */
91:
92: struct lock {
93: #ifdef vax
94: /*
95: * Efficient VAX implementation -- see field description below.
96: */
97: unsigned int read_count:16,
98: want_upgrade:1,
99: want_write:1,
100: waiting:1,
101: can_sleep:1,
102: :0;
103:
104: simple_lock_data_t interlock;
105: #else vax
106: #ifdef ns32000
107: /*
108: * Efficient ns32000 implementation --
109: * see field description below.
110: */
111: simple_lock_data_t interlock;
112: unsigned int read_count:16,
113: want_upgrade:1,
114: want_write:1,
115: waiting:1,
116: can_sleep:1,
117: :0;
118:
119: #else ns32000
120: /* Only the "interlock" field is used for hardware exclusion;
121: * other fields are modified with normal instructions after
122: * acquiring the interlock bit.
123: */
124: simple_lock_data_t
125: interlock; /* Interlock for remaining fields */
126: boolean_t want_write; /* Writer is waiting, or locked for write */
127: boolean_t want_upgrade; /* Read-to-write upgrade waiting */
128: boolean_t waiting; /* Someone is sleeping on lock */
129: boolean_t can_sleep; /* Can attempts to lock go to sleep */
130: int read_count; /* Number of accepted readers */
131: #endif /* ns32000 */
132: #endif /* vax */
133: char *thread; /* Thread that has lock, if recursive locking allowed */
134: /* (should be thread_t, but but we then have mutually
135: recursive definitions) */
136: int recursion_depth;/* Depth of recursion */
137: };
138:
139: typedef struct lock lock_data_t;
140: typedef struct lock *lock_t;
141:
142: #if NCPUS > 1
143: void simple_lock_init();
144: void simple_lock();
145: void simple_unlock();
146: boolean_t simple_lock_try();
147: #else NCPUS > 1
148: /*
149: * No multiprocessor locking is necessary.
150: */
151: #define simple_lock_init(l)
152: #define simple_lock(l)
153: #define simple_unlock(l)
154: #define simple_lock_try(l) (1) /* always succeeds */
155: #endif /* NCPUS > 1 */
156:
157: /* Sleep locks must work even if no multiprocessing */
158:
159: void lock_init();
160: void lock_sleepable();
161: void lock_write();
162: void lock_read();
163: void lock_done();
164: boolean_t lock_read_to_write();
165: void lock_write_to_read();
166: boolean_t lock_try_write();
167: boolean_t lock_try_read();
168: boolean_t lock_try_read_to_write();
169:
170: #define lock_read_done(l) lock_done(l)
171: #define lock_write_done(l) lock_done(l)
172:
173: void lock_set_recursive();
174: void lock_clear_recursive();
175:
1.1.1.2 ! root 176: #endif /* !_VM_LOCK_H_ */
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.