WebSVN – HelenOS – Diff – /branches/tracing/kernel/generic/src/synch/waitq.c



#include <time/timeout.h>
#include <arch.h>
#include <context.h>
#include <adt/list.h>
 
static void waitq_sleep_timed_out(void *data);
 
/** 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() times out.
 * 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_sleep_timed_out(void *data)
{
    thread_t *t = (thread_t *) data;
    waitq_t *wq;
    bool do_wakeup = false;
    DEADLOCK_PROBE_INIT(p_wqlock);

/** Interrupt sleeping thread.
 *
 * This routine attempts to interrupt a thread from its sleep in a waitqueue.
 * If the thread is not found sleeping, no action is taken.
 *
 * @param t     Thread to be interrupted.
 */
void waitq_interrupt_sleep(thread_t *t)
{
    waitq_t *wq;
    bool do_wakeup = false;

 * Sleepers are organised in a 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 flags     Specify mode of the sleep.
 *
 * The sleep can be interrupted only if the
 * SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags.
 *
 * If usec is greater than zero, regardless of the value of the

 * the call will not return until wakeup or interruption comes.
 *
 * If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the
 * call will immediately return, reporting either success or failure.
 *
 * @return      Returns one of ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,
 *          ESYNCH_INTERRUPTED, ESYNCH_OK_ATOMIC and
 *          ESYNCH_OK_BLOCKED.
 *
 * @li  ESYNCH_WOULD_BLOCK means that the sleep failed because at the time of
 *  the call there was no pending wakeup.
 *
 * @li  ESYNCH_TIMEOUT means that the sleep timed out.
 *
 * @li  ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread.
 *
 * @li  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.
 *
 * @li  ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
 *  attempted.
 */
int waitq_sleep_timeout(waitq_t *wq, uint32_t usec, int flags)
{
    ipl_t ipl;
    int rc;

/** Prepare to sleep in a waitq.
 *
 * This function will return holding the lock of the wait queue
 * and interrupts disabled.
 *
 * @param wq        Wait queue.
 *
 * @return      Interrupt level as it existed on entry to this function.
 */
ipl_t waitq_sleep_prepare(waitq_t *wq)
{
    ipl_t ipl;
   

 *
 * This function restores interrupts to the state that existed prior
 * to the call to waitq_sleep_prepare(). If necessary, the wait queue
 * lock is released.
 *
 * @param wq        Wait queue.
 * @param rc        Return code of waitq_sleep_timeout_unsafe().
 * @param ipl       Interrupt level returned by waitq_sleep_prepare().
 */
void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl)
{
    switch (rc) {
    case ESYNCH_WOULD_BLOCK:

}
 
/** Internal implementation of waitq_sleep_timeout().
 *
 * This function implements logic of sleeping in a wait queue.
 * This call must be preceded by a call to waitq_sleep_prepare()
 * and followed by a call to waitq_sleep_finish().
 *
 * @param wq        See waitq_sleep_timeout().
 * @param usec      See waitq_sleep_timeout().
 * @param flags     See waitq_sleep_timeout().
 *
 * @return      See waitq_sleep_timeout().
 */
int waitq_sleep_timeout_unsafe(waitq_t *wq, uint32_t usec, int flags)
{
    /* checks whether to go to sleep at all */
    if (wq->missed_wakeups) {

            spinlock_unlock(&THREAD->lock);
            return ESYNCH_TIMEOUT;
        }
        THREAD->timeout_pending = true;
        timeout_register(&THREAD->sleep_timeout, (uint64_t) usec,
            waitq_sleep_timed_out, THREAD);
    }
 
    list_append(&THREAD->wq_link, &wq->head);
 
    /*

 * wrapper meant for general use.
 *
 * Besides its 'normal' wakeup operation, it attempts to unregister possible
 * timeout.
 *
 * @param wq        Pointer to wait queue.
 * @param mode      Wakeup mode.
 */
void waitq_wakeup(waitq_t *wq, wakeup_mode_t mode)
{
    ipl_t 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 mode      If mode is WAKEUP_FIRST, then the longest waiting
 *          thread, if any, is woken up. If mode is WAKEUP_ALL, then
 *          all waiting threads, if any, are woken up. If there are
 *          no waiting threads to be woken up, the missed wakeup is
 *          recorded in the wait queue.
 */
void _waitq_wakeup_unsafe(waitq_t *wq, wakeup_mode_t mode)
{
    thread_t *t;
    count_t count = 0;

   
    /*
     * Lock the thread prior to removing it from the wq.
     * This is not necessary because of mutual exclusion
     * (the link belongs to the wait queue), but because
     * of synchronization with waitq_sleep_timed_out()
     * and thread_interrupt_sleep().
     *
     * In order for these two functions to work, the following
     * invariant must hold:
     *

Rev 2787	Rev 2925
Line 52...	Line 52...
52	#include <time/timeout.h>	52	#include <time/timeout.h>
53	#include <arch.h>	53	#include <arch.h>
54	#include <context.h>	54	#include <context.h>
55	#include <adt/list.h>	55	#include <adt/list.h>
56		56
57	static void waitq_timeouted_sleep(void *data);	57	static void waitq_sleep_timed_out(void *data);
58		58
59	/** Initialize wait queue	59	/** Initialize wait queue
60	*	60	*
61	* Initialize wait queue.	61	* Initialize wait queue.
62	*	62	*
63	* @param wq Pointer to wait queue to be initialized.	63	* @param wq Pointer to wait queue to be initialized.
64	*/	64	*/
65	void waitq_initialize(waitq_t *wq)	65	void waitq_initialize(waitq_t *wq)
66	{	66	{
67	spinlock_initialize(&wq->lock, "waitq_lock");	67	spinlock_initialize(&wq->lock, "waitq_lock");
68	list_initialize(&wq->head);	68	list_initialize(&wq->head);
69	wq->missed_wakeups = 0;	69	wq->missed_wakeups = 0;
70	}	70	}
71		71
72	/** Handle timeout during waitq_sleep_timeout() call	72	/** Handle timeout during waitq_sleep_timeout() call
73	*	73	*
74	* This routine is called when waitq_sleep_timeout() timeouts.	74	* This routine is called when waitq_sleep_timeout() times out.
75	* Interrupts are disabled.	75	* Interrupts are disabled.
76	*	76	*
77	* It is supposed to try to remove 'its' thread from the wait queue;	77	* It is supposed to try to remove 'its' thread from the wait queue;
78	* it can eventually fail to achieve this goal when these two events	78	* it can eventually fail to achieve this goal when these two events
79	* overlap. In that case it behaves just as though there was no	79	* overlap. In that case it behaves just as though there was no
80	* timeout at all.	80	* timeout at all.
81	*	81	*
82	* @param data Pointer to the thread that called waitq_sleep_timeout().	82	* @param data Pointer to the thread that called waitq_sleep_timeout().
83	*/	83	*/
84	void waitq_timeouted_sleep(void *data)	84	void waitq_sleep_timed_out(void *data)
85	{	85	{
86	thread_t t = (thread_t ) data;	86	thread_t t = (thread_t ) data;
87	waitq_t *wq;	87	waitq_t *wq;
88	bool do_wakeup = false;	88	bool do_wakeup = false;
89	DEADLOCK_PROBE_INIT(p_wqlock);	89	DEADLOCK_PROBE_INIT(p_wqlock);
Line 121...	Line 121...
121	/** Interrupt sleeping thread.	121	/** Interrupt sleeping thread.
122	*	122	*
123	* This routine attempts to interrupt a thread from its sleep in a waitqueue.	123	* This routine attempts to interrupt a thread from its sleep in a waitqueue.
124	* If the thread is not found sleeping, no action is taken.	124	* If the thread is not found sleeping, no action is taken.
125	*	125	*
126	* @param t Thread to be interrupted.	126	* @param t Thread to be interrupted.
127	*/	127	*/
128	void waitq_interrupt_sleep(thread_t *t)	128	void waitq_interrupt_sleep(thread_t *t)
129	{	129	{
130	waitq_t *wq;	130	waitq_t *wq;
131	bool do_wakeup = false;	131	bool do_wakeup = false;
Line 181...	Line 181...
181	* Sleepers are organised in a FIFO fashion in a structure called wait queue.	181	* Sleepers are organised in a FIFO fashion in a structure called wait queue.
182	*	182	*
183	* This function is really basic in that other functions as waitq_sleep()	183	* This function is really basic in that other functions as waitq_sleep()
184	* and all the *_timeout() functions use it.	184	* and all the *_timeout() functions use it.
185	*	185	*
186	* @param wq Pointer to wait queue.	186	* @param wq Pointer to wait queue.
187	* @param usec Timeout in microseconds.	187	* @param usec Timeout in microseconds.
188	* @param flags Specify mode of the sleep.	188	* @param flags Specify mode of the sleep.
189	*	189	*
190	* The sleep can be interrupted only if the	190	* The sleep can be interrupted only if the
191	* SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags.	191	* SYNCH_FLAGS_INTERRUPTIBLE bit is specified in flags.
192	*	192	*
193	* If usec is greater than zero, regardless of the value of the	193	* If usec is greater than zero, regardless of the value of the
Line 198...	Line 198...
198	* the call will not return until wakeup or interruption comes.	198	* the call will not return until wakeup or interruption comes.
199	*	199	*
200	* If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the	200	* If usec is zero and the SYNCH_FLAGS_NON_BLOCKING bit is set in flags, the
201	* call will immediately return, reporting either success or failure.	201	* call will immediately return, reporting either success or failure.
202	*	202	*
203	* @return One of: ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT, ESYNCH_INTERRUPTED,	203	* @return Returns one of ESYNCH_WOULD_BLOCK, ESYNCH_TIMEOUT,
204	* ESYNCH_OK_ATOMIC, ESYNCH_OK_BLOCKED.	204	* ESYNCH_INTERRUPTED, ESYNCH_OK_ATOMIC and
-		205	* ESYNCH_OK_BLOCKED.
205	*	206	*
206	* @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time of the	207	* @li ESYNCH_WOULD_BLOCK means that the sleep failed because at the time of
207	* call there was no pending wakeup.	208	* the call there was no pending wakeup.
208	*	209	*
209	* @li ESYNCH_TIMEOUT means that the sleep timed out.	210	* @li ESYNCH_TIMEOUT means that the sleep timed out.
210	*	211	*
211	* @li ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread.	212	* @li ESYNCH_INTERRUPTED means that somebody interrupted the sleeping thread.
212	*	213	*
213	* @li ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was	214	* @li ESYNCH_OK_ATOMIC means that the sleep succeeded and that there was
214	* a pending wakeup at the time of the call. The caller was not put	215	* a pending wakeup at the time of the call. The caller was not put
215	* asleep at all.	216	* asleep at all.
216	*	217	*
217	* @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was	218	* @li ESYNCH_OK_BLOCKED means that the sleep succeeded; the full sleep was
218	* attempted.	219	* attempted.
219	*/	220	*/
220	int waitq_sleep_timeout(waitq_t *wq, uint32_t usec, int flags)	221	int waitq_sleep_timeout(waitq_t *wq, uint32_t usec, int flags)
221	{	222	{
222	ipl_t ipl;	223	ipl_t ipl;
223	int rc;	224	int rc;
Line 231...	Line 232...
231	/** Prepare to sleep in a waitq.	232	/** Prepare to sleep in a waitq.
232	*	233	*
233	* This function will return holding the lock of the wait queue	234	* This function will return holding the lock of the wait queue
234	* and interrupts disabled.	235	* and interrupts disabled.
235	*	236	*
236	* @param wq Wait queue.	237	* @param wq Wait queue.
237	*	238	*
238	* @return Interrupt level as it existed on entry to this function.	239	* @return Interrupt level as it existed on entry to this function.
239	*/	240	*/
240	ipl_t waitq_sleep_prepare(waitq_t *wq)	241	ipl_t waitq_sleep_prepare(waitq_t *wq)
241	{	242	{
242	ipl_t ipl;	243	ipl_t ipl;
243		244
Line 269...	Line 270...
269	*	270	*
270	* This function restores interrupts to the state that existed prior	271	* This function restores interrupts to the state that existed prior
271	* to the call to waitq_sleep_prepare(). If necessary, the wait queue	272	* to the call to waitq_sleep_prepare(). If necessary, the wait queue
272	* lock is released.	273	* lock is released.
273	*	274	*
274	* @param wq Wait queue.	275	* @param wq Wait queue.
275	* @param rc Return code of waitq_sleep_timeout_unsafe().	276	* @param rc Return code of waitq_sleep_timeout_unsafe().
276	* @param ipl Interrupt level returned by waitq_sleep_prepare().	277	* @param ipl Interrupt level returned by waitq_sleep_prepare().
277	*/	278	*/
278	void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl)	279	void waitq_sleep_finish(waitq_t *wq, int rc, ipl_t ipl)
279	{	280	{
280	switch (rc) {	281	switch (rc) {
281	case ESYNCH_WOULD_BLOCK:	282	case ESYNCH_WOULD_BLOCK:
Line 289...	Line 290...
289	}	290	}
290		291
291	/** Internal implementation of waitq_sleep_timeout().	292	/** Internal implementation of waitq_sleep_timeout().
292	*	293	*
293	* This function implements logic of sleeping in a wait queue.	294	* This function implements logic of sleeping in a wait queue.
294	* This call must be preceeded by a call to waitq_sleep_prepare()	295	* This call must be preceded by a call to waitq_sleep_prepare()
295	* and followed by a call to waitq_slee_finish().	296	* and followed by a call to waitq_sleep_finish().
296	*	297	*
297	* @param wq See waitq_sleep_timeout().	298	* @param wq See waitq_sleep_timeout().
298	* @param usec See waitq_sleep_timeout().	299	* @param usec See waitq_sleep_timeout().
299	* @param flags See waitq_sleep_timeout().	300	* @param flags See waitq_sleep_timeout().
300	*	301	*
301	* @return See waitq_sleep_timeout().	302	* @return See waitq_sleep_timeout().
302	*/	303	*/
303	int waitq_sleep_timeout_unsafe(waitq_t *wq, uint32_t usec, int flags)	304	int waitq_sleep_timeout_unsafe(waitq_t *wq, uint32_t usec, int flags)
304	{	305	{
305	/* checks whether to go to sleep at all */	306	/* checks whether to go to sleep at all */
306	if (wq->missed_wakeups) {	307	if (wq->missed_wakeups) {
Line 353...	Line 354...
353	spinlock_unlock(&THREAD->lock);	354	spinlock_unlock(&THREAD->lock);
354	return ESYNCH_TIMEOUT;	355	return ESYNCH_TIMEOUT;
355	}	356	}
356	THREAD->timeout_pending = true;	357	THREAD->timeout_pending = true;
357	timeout_register(&THREAD->sleep_timeout, (uint64_t) usec,	358	timeout_register(&THREAD->sleep_timeout, (uint64_t) usec,
358	waitq_timeouted_sleep, THREAD);	359	waitq_sleep_timed_out, THREAD);
359	}	360	}
360		361
361	list_append(&THREAD->wq_link, &wq->head);	362	list_append(&THREAD->wq_link, &wq->head);
362		363
363	/*	364	/*
Line 381...	Line 382...
381	* wrapper meant for general use.	382	* wrapper meant for general use.
382	*	383	*
383	* Besides its 'normal' wakeup operation, it attempts to unregister possible	384	* Besides its 'normal' wakeup operation, it attempts to unregister possible
384	* timeout.	385	* timeout.
385	*	386	*
386	* @param wq Pointer to wait queue.	387	* @param wq Pointer to wait queue.
387	* @param mode Wakeup mode.	388	* @param mode Wakeup mode.
388	*/	389	*/
389	void waitq_wakeup(waitq_t *wq, wakeup_mode_t mode)	390	void waitq_wakeup(waitq_t *wq, wakeup_mode_t mode)
390	{	391	{
391	ipl_t ipl;	392	ipl_t ipl;
392		393
Line 402...	Line 403...
402	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()	403	/** Internal SMP- and IRQ-unsafe version of waitq_wakeup()
403	*	404	*
404	* This is the internal SMP- and IRQ-unsafe version of waitq_wakeup(). It	405	* This is the internal SMP- and IRQ-unsafe version of waitq_wakeup(). It
405	* assumes wq->lock is already locked and interrupts are already disabled.	406	* assumes wq->lock is already locked and interrupts are already disabled.
406	*	407	*
407	* @param wq Pointer to wait queue.	408	* @param wq Pointer to wait queue.
408	* @param mode If mode is WAKEUP_FIRST, then the longest waiting thread,	409	* @param mode If mode is WAKEUP_FIRST, then the longest waiting
409	* if any, is woken up. If mode is WAKEUP_ALL, then all	410	* thread, if any, is woken up. If mode is WAKEUP_ALL, then
410	* waiting threads, if any, are woken up. If there are no	411	* all waiting threads, if any, are woken up. If there are
411	* waiting threads to be woken up, the missed wakeup is	412	* no waiting threads to be woken up, the missed wakeup is
412	* recorded in the wait queue.	413	* recorded in the wait queue.
413	*/	414	*/
414	void _waitq_wakeup_unsafe(waitq_t *wq, wakeup_mode_t mode)	415	void _waitq_wakeup_unsafe(waitq_t *wq, wakeup_mode_t mode)
415	{	416	{
416	thread_t *t;	417	thread_t *t;
417	count_t count = 0;	418	count_t count = 0;
Line 429...	Line 430...
429		430
430	/*	431	/*
431	* Lock the thread prior to removing it from the wq.	432	* Lock the thread prior to removing it from the wq.
432	* This is not necessary because of mutual exclusion	433	* This is not necessary because of mutual exclusion
433	* (the link belongs to the wait queue), but because	434	* (the link belongs to the wait queue), but because
434	* of synchronization with waitq_timeouted_sleep()	435	* of synchronization with waitq_sleep_timed_out()
435	* and thread_interrupt_sleep().	436	* and thread_interrupt_sleep().
436	*	437	*
437	* In order for these two functions to work, the following	438	* In order for these two functions to work, the following
438	* invariant must hold:	439	* invariant must hold:
439	*	440	*

Subversion Repositories HelenOS

(root)/branches/tracing/kernel/generic/src/synch/waitq.c – Rev 2787 → 2925