freebsd-skq/lib/libpthread/thread/thr_priority_queue.c
Daniel Eischen 55613576f5 o Don't add a scope system thread's KSE to the list of available
KSEs when it's thread exits; allow the GC handler to do that.

o Make spinlock/spinlock critical regions.

The following were submitted by davidxu

  o Alow thr_switch() to take a null mailbox argument.

  o Better protect cancellation checks.

  o Don't set KSE specific data when creating new KSEs; rely on the
    first upcall of the KSE to set it.

  o Add the ability to set the maximum concurrency level and do this
    automatically.  We should have a way to enable/disable this with
    some sort of tunable because some applications may not want this
    to be the default.

  o Hold the scheduling lock across thread switch calls.

  o If scheduling of a thread fails, make sure to remove it from the list
    of active threads.

  o Better protect accesses to a joining threads when the target thread is
    exited and detached.

  o Remove some macro definitions that are now provided by <sys/kse.h>.

  o Don't leave the library in threaded mode if creation of the initial
    KSE fails.

  o Wakeup idle KSEs when there are threads ready to run.

  o Maintain the number of threads active in the priority queue.
2003-04-28 23:56:12 +00:00

274 lines
7.3 KiB
C

/*
* Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Daniel Eischen.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#include <stdlib.h>
#include <sys/queue.h>
#include <string.h>
#include <pthread.h>
#include "thr_private.h"
/* Prototypes: */
static void pq_insert_prio_list(pq_queue_t *pq, int prio);
#if defined(_PTHREADS_INVARIANTS)
#define PQ_IN_SCHEDQ (THR_FLAGS_IN_RUNQ | THR_FLAGS_IN_WAITQ)
#define PQ_SET_ACTIVE(pq) (pq)->pq_flags |= PQF_ACTIVE
#define PQ_CLEAR_ACTIVE(pq) (pq)->pq_flags &= ~PQF_ACTIVE
#define PQ_ASSERT_ACTIVE(pq, msg) do { \
if (((pq)->pq_flags & PQF_ACTIVE) == 0) \
PANIC(msg); \
} while (0)
#define PQ_ASSERT_INACTIVE(pq, msg) do { \
if (((pq)->pq_flags & PQF_ACTIVE) != 0) \
PANIC(msg); \
} while (0)
#define PQ_ASSERT_IN_WAITQ(thrd, msg) do { \
if (((thrd)->flags & THR_FLAGS_IN_WAITQ) == 0) \
PANIC(msg); \
} while (0)
#define PQ_ASSERT_IN_RUNQ(thrd, msg) do { \
if (((thrd)->flags & THR_FLAGS_IN_RUNQ) == 0) \
PANIC(msg); \
} while (0)
#define PQ_ASSERT_NOT_QUEUED(thrd, msg) do { \
if (((thrd)->flags & PQ_IN_SCHEDQ) != 0) \
PANIC(msg); \
} while (0)
#else
#define PQ_SET_ACTIVE(pq)
#define PQ_CLEAR_ACTIVE(pq)
#define PQ_ASSERT_ACTIVE(pq, msg)
#define PQ_ASSERT_INACTIVE(pq, msg)
#define PQ_ASSERT_IN_WAITQ(thrd, msg)
#define PQ_ASSERT_IN_RUNQ(thrd, msg)
#define PQ_ASSERT_NOT_QUEUED(thrd, msg)
#endif
int
_pq_alloc(pq_queue_t *pq, int minprio, int maxprio)
{
int ret = 0;
int prioslots = maxprio - minprio + 1;
if (pq == NULL)
ret = -1;
/* Create the priority queue with (maxprio - minprio + 1) slots: */
else if ((pq->pq_lists =
(pq_list_t *) malloc(sizeof(pq_list_t) * prioslots)) == NULL)
ret = -1;
else {
/* Remember the queue size: */
pq->pq_size = prioslots;
ret = _pq_init(pq);
}
return (ret);
}
void
_pq_free(pq_queue_t *pq)
{
if ((pq != NULL) && (pq->pq_lists != NULL))
free(pq->pq_lists);
}
int
_pq_init(pq_queue_t *pq)
{
int i, ret = 0;
if ((pq == NULL) || (pq->pq_lists == NULL))
ret = -1;
else {
/* Initialize the queue for each priority slot: */
for (i = 0; i < pq->pq_size; i++) {
TAILQ_INIT(&pq->pq_lists[i].pl_head);
pq->pq_lists[i].pl_prio = i;
pq->pq_lists[i].pl_queued = 0;
}
/* Initialize the priority queue: */
TAILQ_INIT(&pq->pq_queue);
pq->pq_flags = 0;
pq->pq_threads = 0;
}
return (ret);
}
void
_pq_remove(pq_queue_t *pq, pthread_t pthread)
{
int prio = pthread->active_priority;
/*
* Make some assertions when debugging is enabled:
*/
PQ_ASSERT_INACTIVE(pq, "_pq_remove: pq_active");
PQ_SET_ACTIVE(pq);
PQ_ASSERT_IN_RUNQ(pthread, "_pq_remove: Not in priority queue");
/*
* Remove this thread from priority list. Note that if
* the priority list becomes empty, it is not removed
* from the priority queue because another thread may be
* added to the priority list (resulting in a needless
* removal/insertion). Priority lists are only removed
* from the priority queue when _pq_first is called.
*/
TAILQ_REMOVE(&pq->pq_lists[prio].pl_head, pthread, pqe);
pq->pq_threads--;
/* This thread is now longer in the priority queue. */
pthread->flags &= ~THR_FLAGS_IN_RUNQ;
PQ_CLEAR_ACTIVE(pq);
}
void
_pq_insert_head(pq_queue_t *pq, pthread_t pthread)
{
int prio;
/*
* Make some assertions when debugging is enabled:
*/
PQ_ASSERT_INACTIVE(pq, "_pq_insert_head: pq_active");
PQ_SET_ACTIVE(pq);
PQ_ASSERT_NOT_QUEUED(pthread,
"_pq_insert_head: Already in priority queue");
prio = pthread->active_priority;
TAILQ_INSERT_HEAD(&pq->pq_lists[prio].pl_head, pthread, pqe);
if (pq->pq_lists[prio].pl_queued == 0)
/* Insert the list into the priority queue: */
pq_insert_prio_list(pq, prio);
pq->pq_threads++;
/* Mark this thread as being in the priority queue. */
pthread->flags |= THR_FLAGS_IN_RUNQ;
PQ_CLEAR_ACTIVE(pq);
}
void
_pq_insert_tail(pq_queue_t *pq, pthread_t pthread)
{
int prio;
/*
* Make some assertions when debugging is enabled:
*/
PQ_ASSERT_INACTIVE(pq, "_pq_insert_tail: pq_active");
PQ_SET_ACTIVE(pq);
PQ_ASSERT_NOT_QUEUED(pthread,
"_pq_insert_tail: Already in priority queue");
prio = pthread->active_priority;
TAILQ_INSERT_TAIL(&pq->pq_lists[prio].pl_head, pthread, pqe);
if (pq->pq_lists[prio].pl_queued == 0)
/* Insert the list into the priority queue: */
pq_insert_prio_list(pq, prio);
pq->pq_threads++;
/* Mark this thread as being in the priority queue. */
pthread->flags |= THR_FLAGS_IN_RUNQ;
PQ_CLEAR_ACTIVE(pq);
}
pthread_t
_pq_first(pq_queue_t *pq)
{
pq_list_t *pql;
pthread_t pthread = NULL;
/*
* Make some assertions when debugging is enabled:
*/
PQ_ASSERT_INACTIVE(pq, "_pq_first: pq_active");
PQ_SET_ACTIVE(pq);
while (((pql = TAILQ_FIRST(&pq->pq_queue)) != NULL) &&
(pthread == NULL)) {
if ((pthread = TAILQ_FIRST(&pql->pl_head)) == NULL) {
/*
* The priority list is empty; remove the list
* from the queue.
*/
TAILQ_REMOVE(&pq->pq_queue, pql, pl_link);
/* Mark the list as not being in the queue: */
pql->pl_queued = 0;
}
}
PQ_CLEAR_ACTIVE(pq);
return (pthread);
}
static void
pq_insert_prio_list(pq_queue_t *pq, int prio)
{
pq_list_t *pql;
/*
* Make some assertions when debugging is enabled:
*/
PQ_ASSERT_ACTIVE(pq, "pq_insert_prio_list: pq_active");
/*
* The priority queue is in descending priority order. Start at
* the beginning of the queue and find the list before which the
* new list should be inserted.
*/
pql = TAILQ_FIRST(&pq->pq_queue);
while ((pql != NULL) && (pql->pl_prio > prio))
pql = TAILQ_NEXT(pql, pl_link);
/* Insert the list: */
if (pql == NULL)
TAILQ_INSERT_TAIL(&pq->pq_queue, &pq->pq_lists[prio], pl_link);
else
TAILQ_INSERT_BEFORE(pql, &pq->pq_lists[prio], pl_link);
/* Mark this list as being in the queue: */
pq->pq_lists[prio].pl_queued = 1;
}