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c0e366326f
freebsd/lib/libc_r/uthread/uthread_create.c
John Birrell 4a027d50c7 Change signal model to match POSIX (i.e. one set of signal handlers 
for the process, not a separate set for each thread). By default, the
process now only has signal handlers installed for SIGVTALRM, SIGINFO
and SIGCHLD. The thread kernel signal handler is installed for other
signals on demand. This means that SIG_IGN and SIG_DFL processing is now
left to the kernel, not the thread kernel.

Change the signal dispatch to no longer use a signal thread, and
call the signal handler using the stack of the thread that has the
signal pending.

Change the atomic lock method to use test-and-set asm code with
a yield if blocked. This introduces separate locks for each type
of object instead of blocking signals to prevent a context
switch. It was this blocking of signals that caused the performance
degradation the people have noted.

This is a *big* change!
1998-04-29 09:59:34 +00:00

217 lines
6.9 KiB
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/*
* Copyright (c) 1995-1998 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 REGENTS 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.
*
*/
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>
#ifdef _THREAD_SAFE
#include <machine/reg.h>
#include <pthread.h>
#include "pthread_private.h"
#include "libc_private.h"
int
pthread_create(pthread_t * thread, const pthread_attr_t * attr,
void *(*start_routine) (void *), void *arg)
{
int i;
int ret = 0;
int status;
pthread_t new_thread;
pthread_attr_t pattr;
void *stack;
/*
* Locking functions in libc are required when there are
* threads other than the initial thread.
*/
__isthreaded = 1;
/* Allocate memory for the thread structure: */
if ((new_thread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
} else {
/* Check if default thread attributes are required: */
if (attr == NULL || *attr == NULL) {
/* Use the default thread attributes: */
pattr = &pthread_attr_default;
} else {
pattr = *attr;
}
/* Check if a stack was specified in the thread attributes: */
if ((stack = pattr->stackaddr_attr) != NULL) {
}
/* Allocate memory for the stack: */
else if ((stack = (void *) malloc(pattr->stacksize_attr)) == NULL) {
/* Insufficient memory to create a thread: */
ret = EAGAIN;
free(new_thread);
}
/* Check for errors: */
if (ret != 0) {
} else {
/* Initialise the thread structure: */
memset(new_thread, 0, sizeof(struct pthread));
new_thread->slice_usec = -1;
new_thread->sig_saved = 0;
new_thread->stack = stack;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
new_thread->magic = PTHREAD_MAGIC;
if (pattr->suspend == PTHREAD_CREATE_SUSPENDED) {
PTHREAD_NEW_STATE(new_thread,PS_SUSPENDED);
} else {
PTHREAD_NEW_STATE(new_thread,PS_RUNNING);
}
/* Initialise the thread for signals: */
new_thread->sigmask = _thread_run->sigmask;
/* Initialise the jump buffer: */
setjmp(new_thread->saved_jmp_buf);
/*
* Set up new stack frame so that it looks like it
* returned from a longjmp() to the beginning of
* _thread_start().
*/
#if defined(__FreeBSD__)
#if defined(__alpha__)
new_thread->saved_jmp_buf[0]._jb[2] = (long) _thread_start;
new_thread->saved_jmp_buf[0]._jb[4 + R_RA] = 0;
new_thread->saved_jmp_buf[0]._jb[4 + R_T12] = (long) _thread_start;
#else
new_thread->saved_jmp_buf[0]._jb[0] = (long) _thread_start;
#endif
#elif defined(__NetBSD__)
#if defined(__alpha__)
new_thread->saved_jmp_buf[2] = (long) _thread_start;
new_thread->saved_jmp_buf[4 + R_RA] = 0;
new_thread->saved_jmp_buf[4 + R_T12] = (long) _thread_start;
#else
new_thread->saved_jmp_buf[0] = (long) _thread_start;
#endif
#else
#error "Don't recognize this operating system!"
#endif
/* The stack starts high and builds down: */
#if defined(__FreeBSD__)
#if defined(__alpha__)
new_thread->saved_jmp_buf[0]._jb[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
#else
new_thread->saved_jmp_buf[0]._jb[2] = (int) (new_thread->stack + pattr->stacksize_attr - sizeof(double));
#endif
#elif defined(__NetBSD__)
#if defined(__alpha__)
new_thread->saved_jmp_buf[4 + R_SP] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
#else
new_thread->saved_jmp_buf[2] = (long) new_thread->stack + pattr->stacksize_attr - sizeof(double);
#endif
#else
#error "Don't recognize this operating system!"
#endif
/* Copy the thread attributes: */
memcpy(&new_thread->attr, pattr, sizeof(struct pthread_attr));
/*
* Check if this thread is to inherit the scheduling
* attributes from its parent:
*/
if (new_thread->attr.flags & PTHREAD_INHERIT_SCHED) {
/* Copy the scheduling attributes: */
new_thread->pthread_priority = _thread_run->pthread_priority;
new_thread->attr.prio = _thread_run->pthread_priority;
new_thread->attr.schedparam_policy = _thread_run->attr.schedparam_policy;
} else {
/*
* Use just the thread priority, leaving the
* other scheduling attributes as their
* default values:
*/
new_thread->pthread_priority = new_thread->attr.prio;
}
/* Initialise the join queue for the new thread: */
_thread_queue_init(&(new_thread->join_queue));
/* Initialise hooks in the thread structure: */
new_thread->specific_data = NULL;
new_thread->cleanup = NULL;
new_thread->queue = NULL;
new_thread->qnxt = NULL;
new_thread->flags = 0;
/* Lock the thread list: */
_lock_thread_list();
/* Add the thread to the linked list of all threads: */
new_thread->nxt = _thread_link_list;
_thread_link_list = new_thread;
/* Unlock the thread list: */
_unlock_thread_list();
/* Return a pointer to the thread structure: */
(*thread) = new_thread;
/* Schedule the new user thread: */
_thread_kern_sched(NULL);
}
}
/* Return the status: */
return (ret);
}
void
_thread_start(void)
{
/* Run the current thread's start routine with argument: */
pthread_exit(_thread_run->start_routine(_thread_run->arg));
/* This point should never be reached. */
PANIC("Thread has resumed after exit");
}
#endif
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