freebsd-dev/lib/libpthread/thread/thr_find_thread.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

95 lines
3.3 KiB
C

/*
* Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
* Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
* 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 John Birrell.
* 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 JOHN BIRRELL 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 <errno.h>
#include <pthread.h>
#include "thr_private.h"
/*
* Find a thread in the linked list of active threads and add a reference
* to it. Threads with positive reference counts will not be deallocated
* until all references are released.
*/
int
_thr_ref_add(struct pthread *curthread, struct pthread *thread,
int include_dead)
{
kse_critical_t crit;
struct pthread *pthread;
if (thread == NULL)
/* Invalid thread: */
return (EINVAL);
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
TAILQ_FOREACH(pthread, &_thread_list, tle) {
if (pthread == thread) {
if ((include_dead == 0) &&
((pthread->state == PS_DEAD) ||
((pthread->state == PS_DEADLOCK) ||
((pthread->flags & THR_FLAGS_EXITING) != 0))))
pthread = NULL;
else {
thread->refcount++;
curthread->critical_count++;
}
break;
}
}
KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
_kse_critical_leave(crit);
/* Return zero if the thread exists: */
return ((pthread != NULL) ? 0 : ESRCH);
}
void
_thr_ref_delete(struct pthread *curthread, struct pthread *thread)
{
kse_critical_t crit;
if (thread != NULL) {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
thread->refcount--;
curthread->critical_count--;
if ((thread->refcount == 0) &&
(thread->flags & THR_FLAGS_GC_SAFE) != 0)
THR_GCLIST_ADD(thread);
KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
_kse_critical_leave(crit);
}
}