1 /* $NetBSD: sleeptab.h,v 1.3 2023/10/15 10:27:11 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2002, 2006, 2007, 2008, 2009, 2019, 2020
5 * The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Jason R. Thorpe and Andrew Doran.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #ifndef _SYS_SLEEPTAB_H_
34 #define _SYS_SLEEPTAB_H_
35
36 #include <sys/wchan.h>
37
38 struct syncobj;
39
40 #define SLEEPTAB_HASH_SHIFT 7
41 #define SLEEPTAB_HASH_SIZE (1 << SLEEPTAB_HASH_SHIFT)
42 #define SLEEPTAB_HASH_MASK (SLEEPTAB_HASH_SIZE - 1)
43 #define SLEEPTAB_HASH(wchan) (((uintptr_t)(wchan) >> 8) & SLEEPTAB_HASH_MASK)
44
45 LIST_HEAD(sleepq, lwp);
46
47 typedef struct sleeptab {
48 sleepq_t st_queue[SLEEPTAB_HASH_SIZE];
49 } sleeptab_t;
50
51 void sleeptab_init(sleeptab_t *);
52
53 extern sleeptab_t sleeptab;
54
55 #ifdef _KERNEL
56 /*
57 * Find the correct sleep queue for the specified wait channel. This
58 * acquires and holds the per-queue interlock.
59 */
60 static __inline sleepq_t *
sleeptab_lookup(sleeptab_t * st,wchan_t wchan,kmutex_t ** mp)61 sleeptab_lookup(sleeptab_t *st, wchan_t wchan, kmutex_t **mp)
62 {
63 extern sleepqlock_t sleepq_locks[SLEEPTAB_HASH_SIZE];
64 sleepq_t *sq;
65 u_int hash;
66
67 hash = SLEEPTAB_HASH(wchan);
68 sq = &st->st_queue[hash];
69 *mp = &sleepq_locks[hash].lock;
70 mutex_spin_enter(*mp);
71 return sq;
72 }
73
74 static __inline kmutex_t *
sleepq_hashlock(wchan_t wchan)75 sleepq_hashlock(wchan_t wchan)
76 {
77 extern sleepqlock_t sleepq_locks[SLEEPTAB_HASH_SIZE];
78 kmutex_t *mp;
79
80 mp = &sleepq_locks[SLEEPTAB_HASH(wchan)].lock;
81 mutex_spin_enter(mp);
82 return mp;
83 }
84
85 #define sleepq_destroy(a) __nothing
86
87 #endif
88
89 /*
90 * Turnstiles, specialized sleep queues for use by kernel locks.
91 */
92
93 typedef struct turnstile {
94 LIST_ENTRY(turnstile) ts_chain; /* link on hash chain */
95 struct turnstile *ts_free; /* turnstile free list */
96 wchan_t ts_obj; /* lock object */
97 sleepq_t ts_sleepq[2]; /* sleep queues */
98 u_int ts_waiters[2]; /* count of waiters */
99
100 /* priority inheritance */
101 pri_t ts_eprio;
102 lwp_t *ts_inheritor;
103 SLIST_ENTRY(turnstile) ts_pichain;
104 } turnstile_t;
105
106 LIST_HEAD(tschain, turnstile);
107
108 typedef struct tschain tschain_t;
109
110 #define TS_READER_Q 0 /* reader sleep queue */
111 #define TS_WRITER_Q 1 /* writer sleep queue */
112
113 #define TS_WAITERS(ts, q) \
114 (ts)->ts_waiters[(q)]
115
116 #define TS_ALL_WAITERS(ts) \
117 ((ts)->ts_waiters[TS_READER_Q] + \
118 (ts)->ts_waiters[TS_WRITER_Q])
119
120 #define TS_FIRST(ts, q) (LIST_FIRST(&(ts)->ts_sleepq[(q)]))
121
122 #ifdef _KERNEL
123
124 void turnstile_init(void);
125 turnstile_t *turnstile_lookup(wchan_t);
126 void turnstile_ctor(turnstile_t *);
127 void turnstile_exit(wchan_t);
128 void turnstile_block(turnstile_t *, int, wchan_t, const struct syncobj *);
129 void turnstile_wakeup(turnstile_t *, int, int, lwp_t *);
130 void turnstile_print(volatile void *, void (*)(const char *, ...)
131 __printflike(1, 2));
132 void turnstile_unsleep(lwp_t *, bool);
133 void turnstile_changepri(lwp_t *, pri_t);
134
135 extern struct pool turnstile_pool;
136 extern turnstile_t turnstile0;
137
138 #endif /* _KERNEL */
139
140 #endif /* _SYS_SLEEPTAB_H_ */
141