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 <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);
    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 405	Rev 413
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 <arch/asm.h>	33	#include <arch/asm.h>
34	#include <arch/types.h>	34	#include <arch/types.h>
35	#include <time/timeout.h>	35	#include <time/timeout.h>
36	#include <arch.h>	36	#include <arch.h>
37	#include <context.h>	37	#include <context.h>
38	#include <list.h>	38	#include <list.h>
39		39
40	/** Initialize wait queue	40	/** Initialize wait queue
41	*	41	*
42	* Initialize wait queue.	42	* Initialize wait queue.
43	*	43	*
44	* @param wq Pointer to wait queue to be initialized.	44	* @param wq Pointer to wait queue to be initialized.
45	*/	45	*/
46	void waitq_initialize(waitq_t *wq)	46	void waitq_initialize(waitq_t *wq)
47	{	47	{
48	spinlock_initialize(&wq->lock);	48	spinlock_initialize(&wq->lock);
49	list_initialize(&wq->head);	49	list_initialize(&wq->head);
50	wq->missed_wakeups = 0;	50	wq->missed_wakeups = 0;
51	}	51	}
52		52
53	/** Handle timeout during waitq_sleep_timeout() call	53	/** Handle timeout during waitq_sleep_timeout() call
54	*	54	*
55	* This routine is called when waitq_sleep_timeout() timeouts.	55	* This routine is called when waitq_sleep_timeout() timeouts.
56	* Interrupts are disabled.	56	* Interrupts are disabled.
57	*	57	*
58	* It is supposed to try to remove 'its' thread from the wait queue;	58	* It is supposed to try to remove 'its' thread from the wait queue;
59	* it can eventually fail to achieve this goal when these two events	59	* it can eventually fail to achieve this goal when these two events
60	* overlap. In that case it behaves just as though there was no	60	* overlap. In that case it behaves just as though there was no
61	* timeout at all.	61	* timeout at all.
62	*	62	*
63	* @param data Pointer to the thread that called waitq_sleep_timeout().	63	* @param data Pointer to the thread that called waitq_sleep_timeout().
64	*/	64	*/
65	void waitq_interrupted_sleep(void *data)	65	void waitq_interrupted_sleep(void *data)
66	{	66	{
67	thread_t t = (thread_t ) data;	67	thread_t t = (thread_t ) data;
68	waitq_t *wq;	68	waitq_t *wq;
69	int do_wakeup = 0;	69	int do_wakeup = 0;
70		70
71	spinlock_lock(&threads_lock);	71	spinlock_lock(&threads_lock);
72	if (!list_member(&t->threads_link, &threads_head))	72	if (!list_member(&t->threads_link, &threads_head))
73	goto out;	73	goto out;
74		74
75	grab_locks:	75	grab_locks:
76	spinlock_lock(&t->lock);	76	spinlock_lock(&t->lock);
77	if (wq = t->sleep_queue) {	77	if (wq = t->sleep_queue) {
78	if (!spinlock_trylock(&wq->lock)) {	78	if (!spinlock_trylock(&wq->lock)) {
79	spinlock_unlock(&t->lock);	79	spinlock_unlock(&t->lock);
80	goto grab_locks; /* avoid deadlock */	80	goto grab_locks; /* avoid deadlock */
81	}	81	}
82		82
83	list_remove(&t->wq_link);	83	list_remove(&t->wq_link);
84	t->saved_context = t->sleep_timeout_context;	84	t->saved_context = t->sleep_timeout_context;
85	do_wakeup = 1;	85	do_wakeup = 1;
86		86
87	spinlock_unlock(&wq->lock);	87	spinlock_unlock(&wq->lock);
88	t->sleep_queue = NULL;	88	t->sleep_queue = NULL;
89	}	89	}
90		90
91	t->timeout_pending = 0;	91	t->timeout_pending = 0;
92	spinlock_unlock(&t->lock);	92	spinlock_unlock(&t->lock);
93		93
94	if (do_wakeup) thread_ready(t);	94	if (do_wakeup) thread_ready(t);
95		95
96	out:	96	out:
97	spinlock_unlock(&threads_lock);	97	spinlock_unlock(&threads_lock);
98	}	98	}
99		99
100	/** Sleep until either wakeup or timeout occurs	100	/** Sleep until either wakeup or timeout occurs
101	*	101	*
102	* This is a sleep implementation which allows itself to be	102	* This is a sleep implementation which allows itself to be
103	* interrupted from the sleep, restoring a failover context.	103	* interrupted from the sleep, restoring a failover context.
104	*	104	*
105	* Sleepers are organised in FIFO fashion in a structure called wait queue.	105	* Sleepers are organised in FIFO fashion in a structure called wait queue.
106	*	106	*
107	* This function is really basic in that other functions as waitq_sleep()	107	* This function is really basic in that other functions as waitq_sleep()
108	* and all the *_timeout() functions use it.	108	* and all the *_timeout() functions use it.
109	*	109	*
110	* @param wq Pointer to wait queue.	110	* @param wq Pointer to wait queue.
111	* @param usec Timeout in microseconds.	111	* @param usec Timeout in microseconds.
112	* @param nonblocking Blocking vs. non-blocking operation mode switch.	112	* @param nonblocking Blocking vs. non-blocking operation mode switch.
113	*	113	*
114	* If usec is greater than zero, regardless of the value of nonblocking,	114	* If usec is greater than zero, regardless of the value of nonblocking,
115	* the call will not return until either timeout or wakeup comes.	115	* the call will not return until either timeout or wakeup comes.
116	*	116	*
117	* If usec is zero and nonblocking is zero (false), the call	117	* If usec is zero and nonblocking is zero (false), the call
118	* will not return until wakeup comes.	118	* will not return until wakeup comes.
119	*	119	*
120	* If usec is zero and nonblocking is non-zero (true), the call will	120	* If usec is zero and nonblocking is non-zero (true), the call will
121	* immediately return, reporting either success or failure.	121	* immediately return, reporting either success or failure.
122	*	122	*
123	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,	123	* @return Returns one of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,
124	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.	124	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.
125	*	125	*
126	* ESYNCH_WOULD_BLOCK means that the sleep failed because at the time	126	* ESYNCH_WOULD_BLOCK means that the sleep failed because at the time
127	* of the call there was no pending wakeup.	127	* of the call there was no pending wakeup.
128	*	128	*
129	* ESYNCH_TIMEOUT means that the sleep timed out.	129	* ESYNCH_TIMEOUT means that the sleep timed out.
130	*	130	*
131	* ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was	131	* ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was
132	* a pending wakeup at the time of the call. The caller was not put	132	* a pending wakeup at the time of the call. The caller was not put
133	* asleep at all.	133	* asleep at all.
134	*	134	*
135	* ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was	135	* ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
136	* attempted.	136	* attempted.
137	*/	137	*/
138	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)	138	int waitq_sleep_timeout(waitq_t *wq, __u32 usec, int nonblocking)
139	{	139	{
140	volatile pri_t pri; /* must be live after context_restore() */	140	volatile ipl_t ipl; /* must be live after context_restore() */
141		141
142		142
143	restart:	143	restart:
144	pri = cpu_priority_high();	144	ipl = interrupts_disable();
145		145
146	/*	146	/*
147	* Busy waiting for a delayed timeout.	147	* Busy waiting for a delayed timeout.
148	* This is an important fix for the race condition between	148	* This is an important fix for the race condition between
149	* a delayed timeout and a next call to waitq_sleep_timeout().	149	* a delayed timeout and a next call to waitq_sleep_timeout().
150	* Simply, the thread is not allowed to go to sleep if	150	* Simply, the thread is not allowed to go to sleep if
151	* there are timeouts in progress.	151	* there are timeouts in progress.
152	*/	152	*/
153	spinlock_lock(&THREAD->lock);	153	spinlock_lock(&THREAD->lock);
154	if (THREAD->timeout_pending) {	154	if (THREAD->timeout_pending) {
155	spinlock_unlock(&THREAD->lock);	155	spinlock_unlock(&THREAD->lock);
156	cpu_priority_restore(pri);	156	interrupts_restore(ipl);
157	goto restart;	157	goto restart;
158	}	158	}
159	spinlock_unlock(&THREAD->lock);	159	spinlock_unlock(&THREAD->lock);
160		160
161	spinlock_lock(&wq->lock);	161	spinlock_lock(&wq->lock);
162		162
163	/* checks whether to go to sleep at all */	163	/* checks whether to go to sleep at all */
164	if (wq->missed_wakeups) {	164	if (wq->missed_wakeups) {
165	wq->missed_wakeups--;	165	wq->missed_wakeups--;
166	spinlock_unlock(&wq->lock);	166	spinlock_unlock(&wq->lock);
167	cpu_priority_restore(pri);	167	interrupts_restore(ipl);
168	return ESYNCH_OK_ATOMIC;	168	return ESYNCH_OK_ATOMIC;
169	}	169	}
170	else {	170	else {
171	if (nonblocking && (usec == 0)) {	171	if (nonblocking && (usec == 0)) {
172	/* return immediatelly instead of going to sleep */	172	/* return immediatelly instead of going to sleep */
173	spinlock_unlock(&wq->lock);	173	spinlock_unlock(&wq->lock);
174	cpu_priority_restore(pri);	174	interrupts_restore(ipl);
175	return ESYNCH_WOULD_BLOCK;	175	return ESYNCH_WOULD_BLOCK;
176	}	176	}
177	}	177	}
178		178
179		179
180	/*	180	/*
181	* Now we are firmly decided to go to sleep.	181	* Now we are firmly decided to go to sleep.
182	*/	182	*/
183	spinlock_lock(&THREAD->lock);	183	spinlock_lock(&THREAD->lock);
184	if (usec) {	184	if (usec) {
185	/* We use the timeout variant. */	185	/* We use the timeout variant. */
186	if (!context_save(&THREAD->sleep_timeout_context)) {	186	if (!context_save(&THREAD->sleep_timeout_context)) {
187	/*	187	/*
188	* Short emulation of scheduler() return code.	188	* Short emulation of scheduler() return code.
189	*/	189	*/
190	before_thread_runs();	190	before_thread_runs();
191	spinlock_unlock(&THREAD->lock);	191	spinlock_unlock(&THREAD->lock);
192	cpu_priority_restore(pri);	192	interrupts_restore(ipl);
193	return ESYNCH_TIMEOUT;	193	return ESYNCH_TIMEOUT;
194	}	194	}
195	THREAD->timeout_pending = 1;	195	THREAD->timeout_pending = 1;
196	timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);	196	timeout_register(&THREAD->sleep_timeout, (__u64) usec, waitq_interrupted_sleep, THREAD);
197	}	197	}
198		198
199	list_append(&THREAD->wq_link, &wq->head);	199	list_append(&THREAD->wq_link, &wq->head);
200		200
201	/*	201	/*
202	* Suspend execution.	202	* Suspend execution.
203	*/	203	*/
204	THREAD->state = Sleeping;	204	THREAD->state = Sleeping;
205	THREAD->sleep_queue = wq;	205	THREAD->sleep_queue = wq;
206		206
207	spinlock_unlock(&THREAD->lock);	207	spinlock_unlock(&THREAD->lock);
208		208
209	scheduler(); /* wq->lock is released in scheduler_separated_stack() */	209	scheduler(); /* wq->lock is released in scheduler_separated_stack() */
210	cpu_priority_restore(pri);	210	interrupts_restore(ipl);
211		211
212	return ESYNCH_OK_BLOCKED;	212	return ESYNCH_OK_BLOCKED;
213	}	213	}
214		214
215		215
216	/** Wake up first thread sleeping in a wait queue	216	/** Wake up first thread sleeping in a wait queue
217	*	217	*
218	* Wake up first thread sleeping in a wait queue.	218	* Wake up first thread sleeping in a wait queue.
219	* This is the SMP- and IRQ-safe wrapper meant for	219	* This is the SMP- and IRQ-safe wrapper meant for
220	* general use.	220	* general use.
221	*	221	*
222	* Besides its 'normal' wakeup operation, it attempts	222	* Besides its 'normal' wakeup operation, it attempts
223	* to unregister possible timeout.	223	* to unregister possible timeout.
224	*	224	*
225	* @param wq Pointer to wait queue.	225	* @param wq Pointer to wait queue.
226	* @param all If this is non-zero, all sleeping threads	226	* @param all If this is non-zero, all sleeping threads
227	* will be woken up and missed count will be zeroed.	227	* will be woken up and missed count will be zeroed.
228	*/	228	*/
229	void waitq_wakeup(waitq_t *wq, int all)	229	void waitq_wakeup(waitq_t *wq, int all)
230	{	230	{
231	pri_t pri;	231	ipl_t ipl;
232		232
233	pri = cpu_priority_high();	233	ipl = interrupts_disable();
234	spinlock_lock(&wq->lock);	234	spinlock_lock(&wq->lock);
235		235
236	_waitq_wakeup_unsafe(wq, all);	236	_waitq_wakeup_unsafe(wq, all);
237		237
238	spinlock_unlock(&wq->lock);	238	spinlock_unlock(&wq->lock);
239	cpu_priority_restore(pri);	239	interrupts_restore(ipl);
240	}	240	}
241		241
242	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()	242	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()
243	*	243	*
244	* This is the internal SMP- and IRQ-unsafe version	244	* This is the internal SMP- and IRQ-unsafe version
245	* of waitq_wakeup(). It assumes wq->lock is already	245	* of waitq_wakeup(). It assumes wq->lock is already
246	* locked and interrupts are already disabled.	246	* locked and interrupts are already disabled.
247	*	247	*
248	* @param wq Pointer to wait queue.	248	* @param wq Pointer to wait queue.
249	* @param all If this is non-zero, all sleeping threads	249	* @param all If this is non-zero, all sleeping threads
250	* will be woken up and missed count will be zeroed.	250	* will be woken up and missed count will be zeroed.
251	*/	251	*/
252	void _waitq_wakeup_unsafe(waitq_t *wq, int all)	252	void _waitq_wakeup_unsafe(waitq_t *wq, int all)
253	{	253	{
254	thread_t *t;	254	thread_t *t;
255		255
256	loop:	256	loop:
257	if (list_empty(&wq->head)) {	257	if (list_empty(&wq->head)) {
258	wq->missed_wakeups++;	258	wq->missed_wakeups++;
259	if (all) wq->missed_wakeups = 0;	259	if (all) wq->missed_wakeups = 0;
260	return;	260	return;
261	}	261	}
262		262
263	t = list_get_instance(wq->head.next, thread_t, wq_link);	263	t = list_get_instance(wq->head.next, thread_t, wq_link);
264		264
265	list_remove(&t->wq_link);	265	list_remove(&t->wq_link);
266	spinlock_lock(&t->lock);	266	spinlock_lock(&t->lock);
267	if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))	267	if (t->timeout_pending && timeout_unregister(&t->sleep_timeout))
268	t->timeout_pending = 0;	268	t->timeout_pending = 0;
269	t->sleep_queue = NULL;	269	t->sleep_queue = NULL;
270	spinlock_unlock(&t->lock);	270	spinlock_unlock(&t->lock);
271		271
272	thread_ready(t);	272	thread_ready(t);
273		273
274	if (all) goto loop;	274	if (all) goto loop;
275	}	275	}
276		276

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/synch/waitq.c @ 1757 – Rev 405 → 413