source: mainline/kernel/generic/include/synch/waitq.h@ 498b201

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 498b201 was 5c8ba05, checked in by Jakub Jermar <jakub@…>, 18 years ago

Cleanup the waitq_wakeup() interface.
Replace numeric constants (i.e. 0)
and boolean constants (i.e. false) with
more readable WAKEUP_FIRST. Also change the
type of the second argument of waitq_wakeup()
to a newly introduced type wakeup_mode_t.

Fix behaviour of waitq_wakeup() in case
that WAKEUP_ALL semantics is required
but no threads are sleeping in the wait
queue. This is a similar fix to that of
Jan Hudecek committed in the RCU branch,
but, IMHO, is more straightforward and
also doesn't eat up previous missed
wakeups.

  • Property mode set to 100644
File size: 2.7 KB
Line 
1/*
2 * Copyright (c) 2001-2004 Jakub Jermar
3 * 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 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup sync
30 * @{
31 */
32/** @file
33 */
34
35#ifndef KERN_WAITQ_H_
36#define KERN_WAITQ_H_
37
38#include <arch/types.h>
39#include <synch/spinlock.h>
40#include <synch/synch.h>
41#include <adt/list.h>
42
43typedef enum {
44 WAKEUP_FIRST = 0,
45 WAKEUP_ALL
46} wakeup_mode_t;
47
48/** Wait queue structure. */
49typedef struct {
50
51 /** Lock protecting wait queue structure.
52 *
53 * Must be acquired before T.lock for each T of type thread_t.
54 */
55 SPINLOCK_DECLARE(lock);
56
57 /**
58 * Number of waitq_wakeup() calls that didn't find a thread to wake up.
59 */
60 int missed_wakeups;
61 /** List of sleeping threads for wich there was no missed_wakeup. */
62 link_t head;
63} waitq_t;
64
65#define waitq_sleep(wq) \
66 waitq_sleep_timeout((wq), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE)
67
68struct thread;
69
70extern void waitq_initialize(waitq_t *wq);
71extern int waitq_sleep_timeout(waitq_t *wq, uint32_t usec, int flags);
72extern ipl_t waitq_sleep_prepare(waitq_t *wq);
73extern int waitq_sleep_timeout_unsafe(waitq_t *wq, uint32_t usec, int flags);
74extern void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl);
75extern void waitq_wakeup(waitq_t *wq, wakeup_mode_t mode);
76extern void _waitq_wakeup_unsafe(waitq_t *wq, wakeup_mode_t mode);
77extern void waitq_interrupt_sleep(struct thread *t);
78
79#endif
80
81/** @}
82 */
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