4b12016bab
make pthread_yield() more reliable, threads always (I hope) preempted at least every 0.1 sec, as intended. PR: bin/7744 Submitted by: "Richard Seaman, Jr." <dick@tar.com>
236 lines
7.4 KiB
C
236 lines
7.4 KiB
C
/*
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/time.h>
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#ifdef _THREAD_SAFE
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#include <machine/reg.h>
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#include <pthread.h>
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#include "pthread_private.h"
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#include "libc_private.h"
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int
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pthread_create(pthread_t * thread, const pthread_attr_t * attr,
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void *(*start_routine) (void *), void *arg)
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{
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int f_gc = 0;
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int i;
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int ret = 0;
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int status;
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pthread_t gc_thread;
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pthread_t new_thread;
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pthread_attr_t pattr;
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void *stack;
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/*
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* Locking functions in libc are required when there are
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* threads other than the initial thread.
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*/
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__isthreaded = 1;
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/* Allocate memory for the thread structure: */
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if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
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/* Insufficient memory to create a thread: */
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ret = EAGAIN;
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} else {
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/* Check if default thread attributes are required: */
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if (attr == NULL || *attr == NULL) {
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/* Use the default thread attributes: */
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pattr = &pthread_attr_default;
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} else {
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pattr = *attr;
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}
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/* Check if a stack was specified in the thread attributes: */
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if ((stack = pattr->stackaddr_attr) != NULL) {
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}
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/* Allocate memory for the stack: */
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else if ((stack = (void *) malloc(pattr->stacksize_attr)) == NULL) {
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/* Insufficient memory to create a thread: */
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ret = EAGAIN;
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free(new_thread);
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}
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/* Check for errors: */
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if (ret != 0) {
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} else {
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/* Initialise the thread structure: */
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memset(new_thread, 0, sizeof(struct pthread));
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new_thread->slice_usec = -1;
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new_thread->sig_saved = 0;
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new_thread->stack = stack;
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new_thread->start_routine = start_routine;
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new_thread->arg = arg;
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/*
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* Write a magic value to the thread structure
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* to help identify valid ones:
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*/
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new_thread->magic = PTHREAD_MAGIC;
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if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) {
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PTHREAD_NEW_STATE(new_thread,PS_SUSPENDED);
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} else {
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PTHREAD_NEW_STATE(new_thread,PS_RUNNING);
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}
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/* Initialise the thread for signals: */
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new_thread->sigmask = _thread_run->sigmask;
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/* Initialise the jump buffer: */
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setjmp(new_thread->saved_jmp_buf);
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/*
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* Set up new stack frame so that it looks like it
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* returned from a longjmp() to the beginning of
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* _thread_start().
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*/
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#if defined(__FreeBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[0]._jb[2] = (long) _thread_start;
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new_thread->saved_jmp_buf[0]._jb[4 + R_RA] = 0;
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new_thread->saved_jmp_buf[0]._jb[4 + R_T12] = (long) _thread_start;
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#else
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new_thread->saved_jmp_buf[0]._jb[0] = (long) _thread_start;
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#endif
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#elif defined(__NetBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[2] = (long) _thread_start;
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new_thread->saved_jmp_buf[4 + R_RA] = 0;
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new_thread->saved_jmp_buf[4 + R_T12] = (long) _thread_start;
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#else
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new_thread->saved_jmp_buf[0] = (long) _thread_start;
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#endif
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#else
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#error "Don't recognize this operating system!"
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#endif
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/* The stack starts high and builds down: */
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#if defined(__FreeBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[0]._jb[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
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#else
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new_thread->saved_jmp_buf[0]._jb[2] = (int) (new_thread->stack + pattr->stacksize_attr - sizeof(double));
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#endif
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#elif defined(__NetBSD__)
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#if defined(__alpha__)
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new_thread->saved_jmp_buf[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
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#else
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new_thread->saved_jmp_buf[2] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
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#endif
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#else
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#error "Don't recognize this operating system!"
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#endif
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/* Copy the thread attributes: */
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memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
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/*
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* Check if this thread is to inherit the scheduling
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* attributes from its parent:
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*/
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if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) {
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/* Copy the scheduling attributes: */
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new_thread->pthread_priority = _thread_run->pthread_priority;
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new_thread->attr.prio = _thread_run->pthread_priority;
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new_thread->attr.schedparam_policy = _thread_run->attr.schedparam_policy;
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} else {
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/*
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* Use just the thread priority, leaving the
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* other scheduling attributes as their
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* default values:
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*/
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new_thread->pthread_priority = new_thread->attr.prio;
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}
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/* Initialise the join queue for the new thread: */
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_thread_queue_init(&(new_thread->join_queue));
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/* Initialise hooks in the thread structure: */
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new_thread->specific_data = NULL;
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new_thread->cleanup = NULL;
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new_thread->queue = NULL;
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new_thread->qnxt = NULL;
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new_thread->flags = 0;
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/* Lock the thread list: */
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_lock_thread_list();
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/*
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* Check if the garbage collector thread
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* needs to be started.
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*/
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f_gc = (_thread_link_list == _thread_initial);
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/* Add the thread to the linked list of all threads: */
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new_thread->nxt = _thread_link_list;
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_thread_link_list = new_thread;
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/* Unlock the thread list: */
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_unlock_thread_list();
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/* Return a pointer to the thread structure: */
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(*thread) = new_thread;
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/* Schedule the new user thread: */
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_thread_kern_sched(NULL);
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/*
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* Start a garbage collector thread
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* if necessary.
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*/
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if (f_gc && pthread_create(&gc_thread,NULL,
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_thread_gc,NULL) != 0)
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PANIC("Can't create gc thread");
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}
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}
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/* Return the status: */
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return (ret);
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}
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void
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_thread_start(void)
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{
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/* We just left the scheduler via longjmp: */
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_thread_kern_in_sched = 0;
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/* Run the current thread's start routine with argument: */
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pthread_exit(_thread_run->start_routine(_thread_run->arg));
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/* This point should never be reached. */
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PANIC("Thread has resumed after exit");
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}
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#endif
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