freebsd-skq/lib/libthr/thread/thr_create.c
vangyzen abc905bddf _thr_setthreaded() cannot fail; change return type to void
Also remove logic to avoid unnecessary stores to the global variable.
Thread creation and destruction are heavy enough that any supposed savings
is in the noise.

MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
2018-11-30 03:01:32 +00:00

296 lines
8.2 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2003 Daniel M. Eischen <deischen@gdeb.com>
* Copyright (c) 2005, David Xu <davidxu@freebsd.org>
* 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 unmodified, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/types.h>
#include <sys/rtprio.h>
#include <sys/signalvar.h>
#include <errno.h>
#include <link.h>
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <pthread.h>
#include <pthread_np.h>
#include "un-namespace.h"
#include "libc_private.h"
#include "thr_private.h"
static int create_stack(struct pthread_attr *pattr);
static void thread_start(struct pthread *curthread);
__weak_reference(_pthread_create, pthread_create);
int
_pthread_create(pthread_t * __restrict thread,
const pthread_attr_t * __restrict attr, void *(*start_routine) (void *),
void * __restrict arg)
{
struct pthread *curthread, *new_thread;
struct thr_param param;
struct sched_param sched_param;
struct rtprio rtp;
sigset_t set, oset;
cpuset_t *cpusetp;
int i, cpusetsize, create_suspended, locked, old_stack_prot, ret;
cpusetp = NULL;
ret = cpusetsize = 0;
_thr_check_init();
/*
* Tell libc and others now they need lock to protect their data.
*/
if (_thr_isthreaded() == 0) {
_malloc_first_thread();
_thr_setthreaded(1);
}
curthread = _get_curthread();
if ((new_thread = _thr_alloc(curthread)) == NULL)
return (EAGAIN);
memset(&param, 0, sizeof(param));
if (attr == NULL || *attr == NULL)
/* Use the default thread attributes: */
new_thread->attr = _pthread_attr_default;
else {
new_thread->attr = *(*attr);
cpusetp = new_thread->attr.cpuset;
cpusetsize = new_thread->attr.cpusetsize;
new_thread->attr.cpuset = NULL;
new_thread->attr.cpusetsize = 0;
}
if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED) {
/* inherit scheduling contention scope */
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
new_thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
else
new_thread->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
new_thread->attr.prio = curthread->attr.prio;
new_thread->attr.sched_policy = curthread->attr.sched_policy;
}
new_thread->tid = TID_TERMINATED;
old_stack_prot = _rtld_get_stack_prot();
if (create_stack(&new_thread->attr) != 0) {
/* Insufficient memory to create a stack: */
_thr_free(curthread, new_thread);
return (EAGAIN);
}
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
new_thread->magic = THR_MAGIC;
new_thread->start_routine = start_routine;
new_thread->arg = arg;
new_thread->cancel_enable = 1;
new_thread->cancel_async = 0;
/* Initialize the mutex queue: */
for (i = 0; i < TMQ_NITEMS; i++)
TAILQ_INIT(&new_thread->mq[i]);
/* Initialise hooks in the thread structure: */
if (new_thread->attr.suspend == THR_CREATE_SUSPENDED) {
new_thread->flags = THR_FLAGS_NEED_SUSPEND;
create_suspended = 1;
} else {
create_suspended = 0;
}
new_thread->state = PS_RUNNING;
if (new_thread->attr.flags & PTHREAD_CREATE_DETACHED)
new_thread->flags |= THR_FLAGS_DETACHED;
/* Add the new thread. */
new_thread->refcount = 1;
_thr_link(curthread, new_thread);
/*
* Handle the race between __pthread_map_stacks_exec and
* thread linkage.
*/
if (old_stack_prot != _rtld_get_stack_prot())
_thr_stack_fix_protection(new_thread);
/* Return thread pointer eariler so that new thread can use it. */
(*thread) = new_thread;
if (SHOULD_REPORT_EVENT(curthread, TD_CREATE) || cpusetp != NULL) {
THR_THREAD_LOCK(curthread, new_thread);
locked = 1;
} else
locked = 0;
param.start_func = (void (*)(void *)) thread_start;
param.arg = new_thread;
param.stack_base = new_thread->attr.stackaddr_attr;
param.stack_size = new_thread->attr.stacksize_attr;
param.tls_base = (char *)new_thread->tcb;
param.tls_size = sizeof(struct tcb);
param.child_tid = &new_thread->tid;
param.parent_tid = &new_thread->tid;
param.flags = 0;
if (new_thread->attr.flags & PTHREAD_SCOPE_SYSTEM)
param.flags |= THR_SYSTEM_SCOPE;
if (new_thread->attr.sched_inherit == PTHREAD_INHERIT_SCHED)
param.rtp = NULL;
else {
sched_param.sched_priority = new_thread->attr.prio;
_schedparam_to_rtp(new_thread->attr.sched_policy,
&sched_param, &rtp);
param.rtp = &rtp;
}
/* Schedule the new thread. */
if (create_suspended) {
SIGFILLSET(set);
SIGDELSET(set, SIGTRAP);
__sys_sigprocmask(SIG_SETMASK, &set, &oset);
new_thread->sigmask = oset;
SIGDELSET(new_thread->sigmask, SIGCANCEL);
}
ret = thr_new(&param, sizeof(param));
if (ret != 0) {
ret = errno;
/*
* Translate EPROCLIM into well-known POSIX code EAGAIN.
*/
if (ret == EPROCLIM)
ret = EAGAIN;
}
if (create_suspended)
__sys_sigprocmask(SIG_SETMASK, &oset, NULL);
if (ret != 0) {
if (!locked)
THR_THREAD_LOCK(curthread, new_thread);
new_thread->state = PS_DEAD;
new_thread->tid = TID_TERMINATED;
new_thread->flags |= THR_FLAGS_DETACHED;
new_thread->refcount--;
if (new_thread->flags & THR_FLAGS_NEED_SUSPEND) {
new_thread->cycle++;
_thr_umtx_wake(&new_thread->cycle, INT_MAX, 0);
}
_thr_try_gc(curthread, new_thread); /* thread lock released */
atomic_add_int(&_thread_active_threads, -1);
} else if (locked) {
if (cpusetp != NULL) {
if (cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID,
TID(new_thread), cpusetsize, cpusetp)) {
ret = errno;
/* kill the new thread */
new_thread->force_exit = 1;
new_thread->flags |= THR_FLAGS_DETACHED;
_thr_try_gc(curthread, new_thread);
/* thread lock released */
goto out;
}
}
_thr_report_creation(curthread, new_thread);
THR_THREAD_UNLOCK(curthread, new_thread);
}
out:
if (ret)
(*thread) = 0;
return (ret);
}
static int
create_stack(struct pthread_attr *pattr)
{
int ret;
/* Check if a stack was specified in the thread attributes: */
if ((pattr->stackaddr_attr) != NULL) {
pattr->guardsize_attr = 0;
pattr->flags |= THR_STACK_USER;
ret = 0;
}
else
ret = _thr_stack_alloc(pattr);
return (ret);
}
static void
thread_start(struct pthread *curthread)
{
sigset_t set;
if (curthread->attr.suspend == THR_CREATE_SUSPENDED)
set = curthread->sigmask;
/*
* This is used as a serialization point to allow parent
* to report 'new thread' event to debugger or tweak new thread's
* attributes before the new thread does real-world work.
*/
THR_LOCK(curthread);
THR_UNLOCK(curthread);
if (curthread->force_exit)
_pthread_exit(PTHREAD_CANCELED);
if (curthread->attr.suspend == THR_CREATE_SUSPENDED) {
#if 0
/* Done in THR_UNLOCK() */
_thr_ast(curthread);
#endif
/*
* Parent thread have stored signal mask for us,
* we should restore it now.
*/
__sys_sigprocmask(SIG_SETMASK, &set, NULL);
}
#ifdef _PTHREAD_FORCED_UNWIND
curthread->unwind_stackend = (char *)curthread->attr.stackaddr_attr +
curthread->attr.stacksize_attr;
#endif
/* Run the current thread's start routine with argument: */
_pthread_exit(curthread->start_routine(curthread->arg));
/* This point should never be reached. */
PANIC("Thread has resumed after exit");
}