WebSVN – HelenOS – Diff – /trunk/kernel/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 <typedefs.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;
    bool do_wakeup = false;
 
    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)) {        /* assignment */
        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 = true;
       
        spinlock_unlock(&wq->lock);
        t->sleep_queue = NULL;
    }
   
    t->timeout_pending = false;
    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 = true;
        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, bool 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, bool 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 = false;
    t->sleep_queue = NULL;
    spinlock_unlock(&t->lock);
 
    thread_ready(t);
 
    if (all)
        goto loop;
}
 

Rev 557	Rev 615
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 <typedefs.h>	36	#include <typedefs.h>
37	#include <time/timeout.h>	37	#include <time/timeout.h>
38	#include <arch.h>	38	#include <arch.h>
39	#include <context.h>	39	#include <context.h>
40	#include <list.h>	40	#include <list.h>
41		41
42	/** Initialize wait queue	42	/** Initialize wait queue
43	*	43	*
44	* Initialize wait queue.	44	* Initialize wait queue.
45	*	45	*
46	* @param wq Pointer to wait queue to be initialized.	46	* @param wq Pointer to wait queue to be initialized.
47	*/	47	*/
48	void waitq_initialize(waitq_t *wq)	48	void waitq_initialize(waitq_t *wq)
49	{	49	{
50	spinlock_initialize(&wq->lock, "waitq_lock");	50	spinlock_initialize(&wq->lock, "waitq_lock");
51	list_initialize(&wq->head);	51	list_initialize(&wq->head);
52	wq->missed_wakeups = 0;	52	wq->missed_wakeups = 0;
53	}	53	}
54		54
55	/** Handle timeout during waitq_sleep_timeout() call	55	/** Handle timeout during waitq_sleep_timeout() call
56	*	56	*
57	* This routine is called when waitq_sleep_timeout() timeouts.	57	* This routine is called when waitq_sleep_timeout() timeouts.
58	* Interrupts are disabled.	58	* Interrupts are disabled.
59	*	59	*
60	* It is supposed to try to remove 'its' thread from the wait queue;	60	* It is supposed to try to remove 'its' thread from the wait queue;
61	* it can eventually fail to achieve this goal when these two events	61	* it can eventually fail to achieve this goal when these two events
62	* overlap. In that case it behaves just as though there was no	62	* overlap. In that case it behaves just as though there was no
63	* timeout at all.	63	* timeout at all.
64	*	64	*
65	* @param data Pointer to the thread that called waitq_sleep_timeout().	65	* @param data Pointer to the thread that called waitq_sleep_timeout().
66	*/	66	*/
67	void waitq_interrupted_sleep(void *data)	67	void waitq_interrupted_sleep(void *data)
68	{	68	{
69	thread_t t = (thread_t ) data;	69	thread_t t = (thread_t ) data;
70	waitq_t *wq;	70	waitq_t *wq;
71	bool do_wakeup = false;	71	bool do_wakeup = false;
72		72
73	spinlock_lock(&threads_lock);	73	spinlock_lock(&threads_lock);
74	if (!list_member(&t->threads_link, &threads_head))	74	if (!list_member(&t->threads_link, &threads_head))
75	goto out;	75	goto out;
76		76
77	grab_locks:	77	grab_locks:
78	spinlock_lock(&t->lock);	78	spinlock_lock(&t->lock);
79	if (wq = t->sleep_queue) { /* assignment */	79	if ((wq = t->sleep_queue)) { /* assignment */
80	if (!spinlock_trylock(&wq->lock)) {	80	if (!spinlock_trylock(&wq->lock)) {
81	spinlock_unlock(&t->lock);	81	spinlock_unlock(&t->lock);
82	goto grab_locks; /* avoid deadlock */	82	goto grab_locks; /* avoid deadlock */
83	}	83	}
84		84
85	list_remove(&t->wq_link);	85	list_remove(&t->wq_link);
86	t->saved_context = t->sleep_timeout_context;	86	t->saved_context = t->sleep_timeout_context;
87	do_wakeup = true;	87	do_wakeup = true;
88		88
89	spinlock_unlock(&wq->lock);	89	spinlock_unlock(&wq->lock);
90	t->sleep_queue = NULL;	90	t->sleep_queue = NULL;
91	}	91	}
92		92
93	t->timeout_pending = false;	93	t->timeout_pending = false;
94	spinlock_unlock(&t->lock);	94	spinlock_unlock(&t->lock);
95		95
96	if (do_wakeup)	96	if (do_wakeup)
97	thread_ready(t);	97	thread_ready(t);
98		98
99	out:	99	out:
100	spinlock_unlock(&threads_lock);	100	spinlock_unlock(&threads_lock);
101	}	101	}
102		102
103	/** Sleep until either wakeup or timeout occurs	103	/** Sleep until either wakeup or timeout occurs
104	*	104	*
105	* This is a sleep implementation which allows itself to be	105	* This is a sleep implementation which allows itself to be
106	* interrupted from the sleep, restoring a failover context.	106	* interrupted from the sleep, restoring a failover context.
107	*	107	*
108	* Sleepers are organised in FIFO fashion in a structure called wait queue.	108	* Sleepers are organised in FIFO fashion in a structure called wait queue.
109	*	109	*
110	* This function is really basic in that other functions as waitq_sleep()	110	* This function is really basic in that other functions as waitq_sleep()
111	* and all the *_timeout() functions use it.	111	* and all the *_timeout() functions use it.
112	*	112	*
113	* @param wq Pointer to wait queue.	113	* @param wq Pointer to wait queue.
114	* @param usec Timeout in microseconds.	114	* @param usec Timeout in microseconds.
115	* @param nonblocking Blocking vs. non-blocking operation mode switch.	115	* @param nonblocking Blocking vs. non-blocking operation mode switch.
116	*	116	*
117	* If usec is greater than zero, regardless of the value of nonblocking,	117	* If usec is greater than zero, regardless of the value of nonblocking,
118	* the call will not return until either timeout or wakeup comes.	118	* the call will not return until either timeout or wakeup comes.
119	*	119	*
120	* If usec is zero and nonblocking is zero (false), the call	120	* If usec is zero and nonblocking is zero (false), the call
121	* will not return until wakeup comes.	121	* will not return until wakeup comes.
122	*	122	*
123	* If usec is zero and nonblocking is non-zero (true), the call will	123	* If usec is zero and nonblocking is non-zero (true), the call will
124	* immediately return, reporting either success or failure.	124	* immediately return, reporting either success or failure.
125	*	125	*
126	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,	126	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,
127	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.	127	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.
128	*	128	*
129	* ESYNCH_WOULD_BLOCK means that the sleep failed because at the time	129	* ESYNCH_WOULD_BLOCK means that the sleep failed because at the time
130	* of the call there was no pending wakeup.	130	* of the call there was no pending wakeup.
131	*	131	*
132	* ESYNCH_TIMEOUT means that the sleep timed out.	132	* ESYNCH_TIMEOUT means that the sleep timed out.
133	*	133	*
134	* ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was	134	* ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was
135	* a pending wakeup at the time of the call. The caller was not put	135	* a pending wakeup at the time of the call. The caller was not put
136	* asleep at all.	136	* asleep at all.
137	*	137	*
138	* ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was	138	* ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
139	* attempted.	139	* attempted.
140	*/	140	*/
141	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)	141	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)
142	{	142	{
143	volatile ipl_t ipl; /* must be live after context_restore() */	143	volatile ipl_t ipl; /* must be live after context_restore() */
144		144
145		145
146	restart:	146	restart:
147	ipl = interrupts_disable();	147	ipl = interrupts_disable();
148		148
149	/*	149	/*
150	* Busy waiting for a delayed timeout.	150	* Busy waiting for a delayed timeout.
151	* This is an important fix for the race condition between	151	* This is an important fix for the race condition between
152	* a delayed timeout and a next call to waitq_sleep_timeout().	152	* a delayed timeout and a next call to waitq_sleep_timeout().
153	* Simply, the thread is not allowed to go to sleep if	153	* Simply, the thread is not allowed to go to sleep if
154	* there are timeouts in progress.	154	* there are timeouts in progress.
155	*/	155	*/
156	spinlock_lock(&THREAD->lock);	156	spinlock_lock(&THREAD->lock);
157	if (THREAD->timeout_pending) {	157	if (THREAD->timeout_pending) {
158	spinlock_unlock(&THREAD->lock);	158	spinlock_unlock(&THREAD->lock);
159	interrupts_restore(ipl);	159	interrupts_restore(ipl);
160	goto restart;	160	goto restart;
161	}	161	}
162	spinlock_unlock(&THREAD->lock);	162	spinlock_unlock(&THREAD->lock);
163		163
164	spinlock_lock(&wq->lock);	164	spinlock_lock(&wq->lock);
165		165
166	/* checks whether to go to sleep at all */	166	/* checks whether to go to sleep at all */
167	if (wq->missed_wakeups) {	167	if (wq->missed_wakeups) {
168	wq->missed_wakeups--;	168	wq->missed_wakeups--;
169	spinlock_unlock(&wq->lock);	169	spinlock_unlock(&wq->lock);
170	interrupts_restore(ipl);	170	interrupts_restore(ipl);
171	return ESYNCH_OK_ATOMIC;	171	return ESYNCH_OK_ATOMIC;
172	}	172	}
173	else {	173	else {
174	if (nonblocking && (usec == 0)) {	174	if (nonblocking && (usec == 0)) {
175	/* return immediatelly instead of going to sleep */	175	/* return immediatelly instead of going to sleep */
176	spinlock_unlock(&wq->lock);	176	spinlock_unlock(&wq->lock);
177	interrupts_restore(ipl);	177	interrupts_restore(ipl);
178	return ESYNCH_WOULD_BLOCK;	178	return ESYNCH_WOULD_BLOCK;
179	}	179	}
180	}	180	}
181		181
182		182
183	/*	183	/*
184	* Now we are firmly decided to go to sleep.	184	* Now we are firmly decided to go to sleep.
185	*/	185	*/
186	spinlock_lock(&THREAD->lock);	186	spinlock_lock(&THREAD->lock);
187	if (usec) {	187	if (usec) {
188	/* We use the timeout variant. */	188	/* We use the timeout variant. */
189	if (!context_save(&THREAD->sleep_timeout_context)) {	189	if (!context_save(&THREAD->sleep_timeout_context)) {
190	/*	190	/*
191	* Short emulation of scheduler() return code.	191	* Short emulation of scheduler() return code.
192	*/	192	*/
193	before_thread_runs();	193	before_thread_runs();
194	spinlock_unlock(&THREAD->lock);	194	spinlock_unlock(&THREAD->lock);
195	interrupts_restore(ipl);	195	interrupts_restore(ipl);
196	return ESYNCH_TIMEOUT;	196	return ESYNCH_TIMEOUT;
197	}	197	}
198	THREAD->timeout_pending = true;	198	THREAD->timeout_pending = true;
199	timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);	199	timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);
200	}	200	}
201		201
202	list_append(&THREAD->wq_link, &wq->head);	202	list_append(&THREAD->wq_link, &wq->head);
203		203
204	/*	204	/*
205	* Suspend execution.	205	* Suspend execution.
206	*/	206	*/
207	THREAD->state = Sleeping;	207	THREAD->state = Sleeping;
208	THREAD->sleep_queue = wq;	208	THREAD->sleep_queue = wq;
209		209
210	spinlock_unlock(&THREAD->lock);	210	spinlock_unlock(&THREAD->lock);
211		211
212	scheduler(); /* wq->lock is released in scheduler_separated_stack() */	212	scheduler(); /* wq->lock is released in scheduler_separated_stack() */
213	interrupts_restore(ipl);	213	interrupts_restore(ipl);
214		214
215	return ESYNCH_OK_BLOCKED;	215	return ESYNCH_OK_BLOCKED;
216	}	216	}
217		217
218		218
219	/** Wake up first thread sleeping in a wait queue	219	/** Wake up first thread sleeping in a wait queue
220	*	220	*
221	* Wake up first thread sleeping in a wait queue.	221	* Wake up first thread sleeping in a wait queue.
222	* This is the SMP- and IRQ-safe wrapper meant for	222	* This is the SMP- and IRQ-safe wrapper meant for
223	* general use.	223	* general use.
224	*	224	*
225	* Besides its 'normal' wakeup operation, it attempts	225	* Besides its 'normal' wakeup operation, it attempts
226	* to unregister possible timeout.	226	* to unregister possible timeout.
227	*	227	*
228	* @param wq Pointer to wait queue.	228	* @param wq Pointer to wait queue.
229	* @param all If this is non-zero, all sleeping threads	229	* @param all If this is non-zero, all sleeping threads
230	* will be woken up and missed count will be zeroed.	230	* will be woken up and missed count will be zeroed.
231	*/	231	*/
232	void waitq_wakeup(waitq_t *wq, bool all)	232	void waitq_wakeup(waitq_t *wq, bool all)
233	{	233	{
234	ipl_t ipl;	234	ipl_t ipl;
235		235
236	ipl = interrupts_disable();	236	ipl = interrupts_disable();
237	spinlock_lock(&wq->lock);	237	spinlock_lock(&wq->lock);
238		238
239	_waitq_wakeup_unsafe(wq, all);	239	_waitq_wakeup_unsafe(wq, all);
240		240
241	spinlock_unlock(&wq->lock);	241	spinlock_unlock(&wq->lock);
242	interrupts_restore(ipl);	242	interrupts_restore(ipl);
243	}	243	}
244		244
245	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()	245	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()
246	*	246	*
247	* This is the internal SMP- and IRQ-unsafe version	247	* This is the internal SMP- and IRQ-unsafe version
248	* of waitq_wakeup(). It assumes wq->lock is already	248	* of waitq_wakeup(). It assumes wq->lock is already
249	* locked and interrupts are already disabled.	249	* locked and interrupts are already disabled.
250	*	250	*
251	* @param wq Pointer to wait queue.	251	* @param wq Pointer to wait queue.
252	* @param all If this is non-zero, all sleeping threads	252	* @param all If this is non-zero, all sleeping threads
253	* will be woken up and missed count will be zeroed.	253	* will be woken up and missed count will be zeroed.
254	*/	254	*/
255	void _waitq_wakeup_unsafe(waitq_t *wq, bool all)	255	void _waitq_wakeup_unsafe(waitq_t *wq, bool all)
256	{	256	{
257	thread_t *t;	257	thread_t *t;
258		258
259	loop:	259	loop:
260	if (list_empty(&wq->head)) {	260	if (list_empty(&wq->head)) {
261	wq->missed_wakeups++;	261	wq->missed_wakeups++;
262	if (all)	262	if (all)
263	wq->missed_wakeups = 0;	263	wq->missed_wakeups = 0;
264	return;	264	return;
265	}	265	}
266		266
267	t = list_get_instance(wq->head.next, thread_t, wq_link);	267	t = list_get_instance(wq->head.next, thread_t, wq_link);
268		268
269	list_remove(&t->wq_link);	269	list_remove(&t->wq_link);
270	spinlock_lock(&t->lock);	270	spinlock_lock(&t->lock);
271	if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))	271	if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))
272	t->timeout_pending = false;	272	t->timeout_pending = false;
273	t->sleep_queue = NULL;	273	t->sleep_queue = NULL;
274	spinlock_unlock(&t->lock);	274	spinlock_unlock(&t->lock);
275		275
276	thread_ready(t);	276	thread_ready(t);
277		277
278	if (all)	278	if (all)
279	goto loop;	279	goto loop;
280	}	280	}
281		281

Subversion Repositories HelenOS

(root)/trunk/kernel/generic/src/synch/waitq.c @ 4537 – Rev 557 → 615