WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/synch/waitq.c


/*
 * Copyright (C) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.
 */
 
#include <synch/waitq.h>
#include <synch/synch.h>
#include <synch/spinlock.h>
#include <proc/thread.h>
#include <proc/scheduler.h>
#include <arch/asm.h>
#include <arch/types.h>
#include <time/timeout.h>
#include <arch.h>
#include <context.h>
#include <list.h>
 
/** Initialize wait queue
 *
 * Initialize wait queue.
 *
 * @param wq Pointer to wait queue to be initialized.
 */
void waitq_initialize(waitq_t *wq)
{
    spinlock_initialize(&wq->lock, "waitq_lock");
    list_initialize(&wq->head);
    wq->missed_wakeups = 0;
}
 
/** Handle timeout during waitq_sleep_timeout() call
 *
 * This routine is called when waitq_sleep_timeout() timeouts.
 * Interrupts are disabled.
 *
 * It is supposed to try to remove 'its' thread from the wait queue;
 * it can eventually fail to achieve this goal when these two events
 * overlap. In that case it behaves just as though there was no
 * timeout at all.
 *
 * @param data Pointer to the thread that called waitq_sleep_timeout().
 */
void waitq_interrupted_sleep(void *data)
{
    thread_t *t = (thread_t *) data;
    waitq_t *wq;
    int do_wakeup = 0;
 
    spinlock_lock(&threads_lock);
    if (!list_member(&t->threads_link, &threads_head))
        goto out;
 
grab_locks:
    spinlock_lock(&t->lock);
    if (wq = t->sleep_queue) {
        if (!spinlock_trylock(&wq->lock)) {
            spinlock_unlock(&t->lock);
            goto grab_locks; /* avoid deadlock */
        }
 
        list_remove(&t->wq_link);
        t->saved_context = t->sleep_timeout_context;
        do_wakeup = 1;
       
        spinlock_unlock(&wq->lock);
        t->sleep_queue = NULL;
    }
   
    t->timeout_pending = 0;
    spinlock_unlock(&t->lock);
   
    if (do_wakeup) thread_ready(t);
 
out:
    spinlock_unlock(&threads_lock);
}
 
/** Sleep until either wakeup or timeout occurs
 *
 * This is a sleep implementation which allows itself to be
 * interrupted from the sleep, restoring a failover context.
 *
 * Sleepers are organised in FIFO fashion in a structure called wait queue.
 *
 * This function is really basic in that other functions as waitq_sleep()
 * and all the *_timeout() functions use it.
 *
 * @param wq Pointer to wait queue.
 * @param usec Timeout in microseconds.
 * @param nonblocking Blocking vs. non-blocking operation mode switch.
 *
 * If usec is greater than zero, regardless of the value of nonblocking,
 * the call will not return until either timeout or wakeup comes.
 *
 * If usec is zero and nonblocking is zero (false), the call
 * will not return until wakeup comes.
 *
 * If usec is zero and nonblocking is non-zero (true), the call will
 * immediately return, reporting either success or failure.
 *
 * @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,
 *         ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.
 *
 * ESYNCH_WOULD_BLOCK means that the sleep failed because at the time
 * of the call there was no pending wakeup.
 *
 * ESYNCH_TIMEOUT means that the sleep timed out.
 *
 * ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was
 * a pending wakeup at the time of the call. The caller was not put
 * asleep at all.
 *
 * ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
 * attempted.
 */
int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)
{
    volatile ipl_t ipl; /* must be live after context_restore() */
   
   
restart:
    ipl = interrupts_disable();
   
    /*
     * Busy waiting for a delayed timeout.
     * This is an important fix for the race condition between
     * a delayed timeout and a next call to waitq_sleep_timeout().
     * Simply, the thread is not allowed to go to sleep if
     * there are timeouts in progress.
     */
    spinlock_lock(&THREAD->lock);
    if (THREAD->timeout_pending) {
        spinlock_unlock(&THREAD->lock);
        interrupts_restore(ipl);       
        goto restart;
    }
    spinlock_unlock(&THREAD->lock);
   
    spinlock_lock(&wq->lock);
   
    /* checks whether to go to sleep at all */
    if (wq->missed_wakeups) {
        wq->missed_wakeups--;
        spinlock_unlock(&wq->lock);
        interrupts_restore(ipl);
        return ESYNCH_OK_ATOMIC;
    }
    else {
        if (nonblocking && (usec == 0)) {
            /* return immediatelly instead of going to sleep */
            spinlock_unlock(&wq->lock);
            interrupts_restore(ipl);
            return ESYNCH_WOULD_BLOCK;
        }
    }
 
   
    /*
     * Now we are firmly decided to go to sleep.
     */
    spinlock_lock(&THREAD->lock);
    if (usec) {
        /* We use the timeout variant. */
        if (!context_save(&THREAD->sleep_timeout_context)) {
            /*
             * Short emulation of scheduler() return code.
             */
            before_thread_runs();
            spinlock_unlock(&THREAD->lock);
            interrupts_restore(ipl);
            return ESYNCH_TIMEOUT;
        }
        THREAD->timeout_pending = 1;
        timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);
    }
 
    list_append(&THREAD->wq_link, &wq->head);
 
    /*
     * Suspend execution.
     */
    THREAD->state = Sleeping;
    THREAD->sleep_queue = wq;
 
    spinlock_unlock(&THREAD->lock);
 
    scheduler();    /* wq->lock is released in scheduler_separated_stack() */
    interrupts_restore(ipl);
   
    return ESYNCH_OK_BLOCKED;
}
 
 
/** Wake up first thread sleeping in a wait queue
 *
 * Wake up first thread sleeping in a wait queue.
 * This is the SMP- and IRQ-safe wrapper meant for
 * general use.
 *
 * Besides its 'normal' wakeup operation, it attempts
 * to unregister possible timeout.
 *
 * @param wq Pointer to wait queue.
 * @param all If this is non-zero, all sleeping threads
 *        will be woken up and missed count will be zeroed.
 */
void waitq_wakeup(waitq_t *wq, int all)
{
    ipl_t ipl;
 
    ipl = interrupts_disable();
    spinlock_lock(&wq->lock);
 
    _waitq_wakeup_unsafe(wq, all);
 
    spinlock_unlock(&wq->lock);
    interrupts_restore(ipl);   
}
 
/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()
 *
 * This is the internal SMP- and IRQ-unsafe version
 * of waitq_wakeup(). It assumes wq->lock is already
 * locked and interrupts are already disabled.
 *
 * @param wq Pointer to wait queue.
 * @param all If this is non-zero, all sleeping threads
 *        will be woken up and missed count will be zeroed.
 */
void _waitq_wakeup_unsafe(waitq_t *wq, int all)
{
    thread_t *t;
 
loop:  
    if (list_empty(&wq->head)) {
        wq->missed_wakeups++;
        if (all) wq->missed_wakeups = 0;
        return;
    }
 
    t = list_get_instance(wq->head.next, thread_t, wq_link);
   
    list_remove(&t->wq_link);
    spinlock_lock(&t->lock);
    if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))
        t->timeout_pending = 0;
    t->sleep_queue = NULL;
    spinlock_unlock(&t->lock);
 
    thread_ready(t);
 
    if (all) goto loop;
}
 

Rev 534	Rev 552
1	/*	1	/*
2	* Copyright (C) 2001-2004 Jakub Jermar	2	* Copyright (C) 2001-2004 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	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	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.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	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	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	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	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	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	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.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	#include <synch/waitq.h>	29	#include <synch/waitq.h>
30	#include <synch/synch.h>	30	#include <synch/synch.h>
31	#include <synch/spinlock.h>	31	#include <synch/spinlock.h>
32	#include <proc/thread.h>	32	#include <proc/thread.h>
33	#include <proc/scheduler.h>	33	#include <proc/scheduler.h>
34	#include <arch/asm.h>	34	#include <arch/asm.h>
35	#include <arch/types.h>	35	#include <arch/types.h>
36	#include <time/timeout.h>	36	#include <time/timeout.h>
37	#include <arch.h>	37	#include <arch.h>
38	#include <context.h>	38	#include <context.h>
39	#include <list.h>	39	#include <list.h>
40		40
41	/** Initialize wait queue	41	/** Initialize wait queue
42	*	42	*
43	* Initialize wait queue.	43	* Initialize wait queue.
44	*	44	*
45	* @param wq Pointer to wait queue to be initialized.	45	* @param wq Pointer to wait queue to be initialized.
46	*/	46	*/
47	void waitq_initialize(waitq_t *wq)	47	void waitq_initialize(waitq_t *wq)
48	{	48	{
49	spinlock_initialize(&wq->lock);	49	spinlock_initialize(&wq->lock, "waitq_lock");
50	list_initialize(&wq->head);	50	list_initialize(&wq->head);
51	wq->missed_wakeups = 0;	51	wq->missed_wakeups = 0;
52	}	52	}
53		53
54	/** Handle timeout during waitq_sleep_timeout() call	54	/** Handle timeout during waitq_sleep_timeout() call
55	*	55	*
56	* This routine is called when waitq_sleep_timeout() timeouts.	56	* This routine is called when waitq_sleep_timeout() timeouts.
57	* Interrupts are disabled.	57	* Interrupts are disabled.
58	*	58	*
59	* It is supposed to try to remove 'its' thread from the wait queue;	59	* It is supposed to try to remove 'its' thread from the wait queue;
60	* it can eventually fail to achieve this goal when these two events	60	* it can eventually fail to achieve this goal when these two events
61	* overlap. In that case it behaves just as though there was no	61	* overlap. In that case it behaves just as though there was no
62	* timeout at all.	62	* timeout at all.
63	*	63	*
64	* @param data Pointer to the thread that called waitq_sleep_timeout().	64	* @param data Pointer to the thread that called waitq_sleep_timeout().
65	*/	65	*/
66	void waitq_interrupted_sleep(void *data)	66	void waitq_interrupted_sleep(void *data)
67	{	67	{
68	thread_t t = (thread_t ) data;	68	thread_t t = (thread_t ) data;
69	waitq_t *wq;	69	waitq_t *wq;
70	int do_wakeup = 0;	70	int do_wakeup = 0;
71		71
72	spinlock_lock(&threads_lock);	72	spinlock_lock(&threads_lock);
73	if (!list_member(&t->threads_link, &threads_head))	73	if (!list_member(&t->threads_link, &threads_head))
74	goto out;	74	goto out;
75		75
76	grab_locks:	76	grab_locks:
77	spinlock_lock(&t->lock);	77	spinlock_lock(&t->lock);
78	if (wq = t->sleep_queue) {	78	if (wq = t->sleep_queue) {
79	if (!spinlock_trylock(&wq->lock)) {	79	if (!spinlock_trylock(&wq->lock)) {
80	spinlock_unlock(&t->lock);	80	spinlock_unlock(&t->lock);
81	goto grab_locks; /* avoid deadlock */	81	goto grab_locks; /* avoid deadlock */
82	}	82	}
83		83
84	list_remove(&t->wq_link);	84	list_remove(&t->wq_link);
85	t->saved_context = t->sleep_timeout_context;	85	t->saved_context = t->sleep_timeout_context;
86	do_wakeup = 1;	86	do_wakeup = 1;
87		87
88	spinlock_unlock(&wq->lock);	88	spinlock_unlock(&wq->lock);
89	t->sleep_queue = NULL;	89	t->sleep_queue = NULL;
90	}	90	}
91		91
92	t->timeout_pending = 0;	92	t->timeout_pending = 0;
93	spinlock_unlock(&t->lock);	93	spinlock_unlock(&t->lock);
94		94
95	if (do_wakeup) thread_ready(t);	95	if (do_wakeup) thread_ready(t);
96		96
97	out:	97	out:
98	spinlock_unlock(&threads_lock);	98	spinlock_unlock(&threads_lock);
99	}	99	}
100		100
101	/** Sleep until either wakeup or timeout occurs	101	/** Sleep until either wakeup or timeout occurs
102	*	102	*
103	* This is a sleep implementation which allows itself to be	103	* This is a sleep implementation which allows itself to be
104	* interrupted from the sleep, restoring a failover context.	104	* interrupted from the sleep, restoring a failover context.
105	*	105	*
106	* Sleepers are organised in FIFO fashion in a structure called wait queue.	106	* Sleepers are organised in FIFO fashion in a structure called wait queue.
107	*	107	*
108	* This function is really basic in that other functions as waitq_sleep()	108	* This function is really basic in that other functions as waitq_sleep()
109	* and all the *_timeout() functions use it.	109	* and all the *_timeout() functions use it.
110	*	110	*
111	* @param wq Pointer to wait queue.	111	* @param wq Pointer to wait queue.
112	* @param usec Timeout in microseconds.	112	* @param usec Timeout in microseconds.
113	* @param nonblocking Blocking vs. non-blocking operation mode switch.	113	* @param nonblocking Blocking vs. non-blocking operation mode switch.
114	*	114	*
115	* If usec is greater than zero, regardless of the value of nonblocking,	115	* If usec is greater than zero, regardless of the value of nonblocking,
116	* the call will not return until either timeout or wakeup comes.	116	* the call will not return until either timeout or wakeup comes.
117	*	117	*
118	* If usec is zero and nonblocking is zero (false), the call	118	* If usec is zero and nonblocking is zero (false), the call
119	* will not return until wakeup comes.	119	* will not return until wakeup comes.
120	*	120	*
121	* If usec is zero and nonblocking is non-zero (true), the call will	121	* If usec is zero and nonblocking is non-zero (true), the call will
122	* immediately return, reporting either success or failure.	122	* immediately return, reporting either success or failure.
123	*	123	*
124	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,	124	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,
125	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.	125	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.
126	*	126	*
127	* ESYNCH_WOULD_BLOCK means that the sleep failed because at the time	127	* ESYNCH_WOULD_BLOCK means that the sleep failed because at the time
128	* of the call there was no pending wakeup.	128	* of the call there was no pending wakeup.
129	*	129	*
130	* ESYNCH_TIMEOUT means that the sleep timed out.	130	* ESYNCH_TIMEOUT means that the sleep timed out.
131	*	131	*
132	* ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was	132	* ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was
133	* a pending wakeup at the time of the call. The caller was not put	133	* a pending wakeup at the time of the call. The caller was not put
134	* asleep at all.	134	* asleep at all.
135	*	135	*
136	* ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was	136	* ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
137	* attempted.	137	* attempted.
138	*/	138	*/
139	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)	139	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)
140	{	140	{
141	volatile ipl_t ipl; /* must be live after context_restore() */	141	volatile ipl_t ipl; /* must be live after context_restore() */
142		142
143		143
144	restart:	144	restart:
145	ipl = interrupts_disable();	145	ipl = interrupts_disable();
146		146
147	/*	147	/*
148	* Busy waiting for a delayed timeout.	148	* Busy waiting for a delayed timeout.
149	* This is an important fix for the race condition between	149	* This is an important fix for the race condition between
150	* a delayed timeout and a next call to waitq_sleep_timeout().	150	* a delayed timeout and a next call to waitq_sleep_timeout().
151	* Simply, the thread is not allowed to go to sleep if	151	* Simply, the thread is not allowed to go to sleep if
152	* there are timeouts in progress.	152	* there are timeouts in progress.
153	*/	153	*/
154	spinlock_lock(&THREAD->lock);	154	spinlock_lock(&THREAD->lock);
155	if (THREAD->timeout_pending) {	155	if (THREAD->timeout_pending) {
156	spinlock_unlock(&THREAD->lock);	156	spinlock_unlock(&THREAD->lock);
157	interrupts_restore(ipl);	157	interrupts_restore(ipl);
158	goto restart;	158	goto restart;
159	}	159	}
160	spinlock_unlock(&THREAD->lock);	160	spinlock_unlock(&THREAD->lock);
161		161
162	spinlock_lock(&wq->lock);	162	spinlock_lock(&wq->lock);
163		163
164	/* checks whether to go to sleep at all */	164	/* checks whether to go to sleep at all */
165	if (wq->missed_wakeups) {	165	if (wq->missed_wakeups) {
166	wq->missed_wakeups--;	166	wq->missed_wakeups--;
167	spinlock_unlock(&wq->lock);	167	spinlock_unlock(&wq->lock);
168	interrupts_restore(ipl);	168	interrupts_restore(ipl);
169	return ESYNCH_OK_ATOMIC;	169	return ESYNCH_OK_ATOMIC;
170	}	170	}
171	else {	171	else {
172	if (nonblocking && (usec == 0)) {	172	if (nonblocking && (usec == 0)) {
173	/* return immediatelly instead of going to sleep */	173	/* return immediatelly instead of going to sleep */
174	spinlock_unlock(&wq->lock);	174	spinlock_unlock(&wq->lock);
175	interrupts_restore(ipl);	175	interrupts_restore(ipl);
176	return ESYNCH_WOULD_BLOCK;	176	return ESYNCH_WOULD_BLOCK;
177	}	177	}
178	}	178	}
179		179
180		180
181	/*	181	/*
182	* Now we are firmly decided to go to sleep.	182	* Now we are firmly decided to go to sleep.
183	*/	183	*/
184	spinlock_lock(&THREAD->lock);	184	spinlock_lock(&THREAD->lock);
185	if (usec) {	185	if (usec) {
186	/* We use the timeout variant. */	186	/* We use the timeout variant. */
187	if (!context_save(&THREAD->sleep_timeout_context)) {	187	if (!context_save(&THREAD->sleep_timeout_context)) {
188	/*	188	/*
189	* Short emulation of scheduler() return code.	189	* Short emulation of scheduler() return code.
190	*/	190	*/
191	before_thread_runs();	191	before_thread_runs();
192	spinlock_unlock(&THREAD->lock);	192	spinlock_unlock(&THREAD->lock);
193	interrupts_restore(ipl);	193	interrupts_restore(ipl);
194	return ESYNCH_TIMEOUT;	194	return ESYNCH_TIMEOUT;
195	}	195	}
196	THREAD->timeout_pending = 1;	196	THREAD->timeout_pending = 1;
197	timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);	197	timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);
198	}	198	}
199		199
200	list_append(&THREAD->wq_link, &wq->head);	200	list_append(&THREAD->wq_link, &wq->head);
201		201
202	/*	202	/*
203	* Suspend execution.	203	* Suspend execution.
204	*/	204	*/
205	THREAD->state = Sleeping;	205	THREAD->state = Sleeping;
206	THREAD->sleep_queue = wq;	206	THREAD->sleep_queue = wq;
207		207
208	spinlock_unlock(&THREAD->lock);	208	spinlock_unlock(&THREAD->lock);
209		209
210	scheduler(); /* wq->lock is released in scheduler_separated_stack() */	210	scheduler(); /* wq->lock is released in scheduler_separated_stack() */
211	interrupts_restore(ipl);	211	interrupts_restore(ipl);
212		212
213	return ESYNCH_OK_BLOCKED;	213	return ESYNCH_OK_BLOCKED;
214	}	214	}
215		215
216		216
217	/** Wake up first thread sleeping in a wait queue	217	/** Wake up first thread sleeping in a wait queue
218	*	218	*
219	* Wake up first thread sleeping in a wait queue.	219	* Wake up first thread sleeping in a wait queue.
220	* This is the SMP- and IRQ-safe wrapper meant for	220	* This is the SMP- and IRQ-safe wrapper meant for
221	* general use.	221	* general use.
222	*	222	*
223	* Besides its 'normal' wakeup operation, it attempts	223	* Besides its 'normal' wakeup operation, it attempts
224	* to unregister possible timeout.	224	* to unregister possible timeout.
225	*	225	*
226	* @param wq Pointer to wait queue.	226	* @param wq Pointer to wait queue.
227	* @param all If this is non-zero, all sleeping threads	227	* @param all If this is non-zero, all sleeping threads
228	* will be woken up and missed count will be zeroed.	228	* will be woken up and missed count will be zeroed.
229	*/	229	*/
230	void waitq_wakeup(waitq_t *wq, int all)	230	void waitq_wakeup(waitq_t *wq, int all)
231	{	231	{
232	ipl_t ipl;	232	ipl_t ipl;
233		233
234	ipl = interrupts_disable();	234	ipl = interrupts_disable();
235	spinlock_lock(&wq->lock);	235	spinlock_lock(&wq->lock);
236		236
237	_waitq_wakeup_unsafe(wq, all);	237	_waitq_wakeup_unsafe(wq, all);
238		238
239	spinlock_unlock(&wq->lock);	239	spinlock_unlock(&wq->lock);
240	interrupts_restore(ipl);	240	interrupts_restore(ipl);
241	}	241	}
242		242
243	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()	243	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()
244	*	244	*
245	* This is the internal SMP- and IRQ-unsafe version	245	* This is the internal SMP- and IRQ-unsafe version
246	* of waitq_wakeup(). It assumes wq->lock is already	246	* of waitq_wakeup(). It assumes wq->lock is already
247	* locked and interrupts are already disabled.	247	* locked and interrupts are already disabled.
248	*	248	*
249	* @param wq Pointer to wait queue.	249	* @param wq Pointer to wait queue.
250	* @param all If this is non-zero, all sleeping threads	250	* @param all If this is non-zero, all sleeping threads
251	* will be woken up and missed count will be zeroed.	251	* will be woken up and missed count will be zeroed.
252	*/	252	*/
253	void _waitq_wakeup_unsafe(waitq_t *wq, int all)	253	void _waitq_wakeup_unsafe(waitq_t *wq, int all)
254	{	254	{
255	thread_t *t;	255	thread_t *t;
256		256
257	loop:	257	loop:
258	if (list_empty(&wq->head)) {	258	if (list_empty(&wq->head)) {
259	wq->missed_wakeups++;	259	wq->missed_wakeups++;
260	if (all) wq->missed_wakeups = 0;	260	if (all) wq->missed_wakeups = 0;
261	return;	261	return;
262	}	262	}
263		263
264	t = list_get_instance(wq->head.next, thread_t, wq_link);	264	t = list_get_instance(wq->head.next, thread_t, wq_link);
265		265
266	list_remove(&t->wq_link);	266	list_remove(&t->wq_link);
267	spinlock_lock(&t->lock);	267	spinlock_lock(&t->lock);
268	if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))	268	if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))
269	t->timeout_pending = 0;	269	t->timeout_pending = 0;
270	t->sleep_queue = NULL;	270	t->sleep_queue = NULL;
271	spinlock_unlock(&t->lock);	271	spinlock_unlock(&t->lock);
272		272
273	thread_ready(t);	273	thread_ready(t);
274		274
275	if (all) goto loop;	275	if (all) goto loop;
276	}	276	}
277		277

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(root)/kernel/trunk/generic/src/synch/waitq.c – Rev 534 → 552