4777259ff2
mangling results. Fixes regression in test yield2, dating to 2003/1/2 when pthread__locked_switch() was changed to not store the saved-context pointer until after switching stacks. Note to self: regression tests exist to be run.
255 lines
8.0 KiB
C
255 lines
8.0 KiB
C
/* $NetBSD: pthread_run.c,v 1.9 2003/04/04 01:08:25 nathanw Exp $ */
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/*-
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* Copyright (c) 2001 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Nathan J. Williams.
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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 the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: pthread_run.c,v 1.9 2003/04/04 01:08:25 nathanw Exp $");
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#include <ucontext.h>
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#include "pthread.h"
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#include "pthread_int.h"
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#ifdef PTHREAD_RUN_DEBUG
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#define SDPRINTF(x) DPRINTF(x)
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#else
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#define SDPRINTF(x)
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#endif
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extern pthread_spin_t pthread__runqueue_lock;
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extern struct pthread_queue_t pthread__runqueue;
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extern struct pthread_queue_t pthread__idlequeue;
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extern pthread_spin_t pthread__deadqueue_lock;
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extern struct pthread_queue_t pthread__reidlequeue;
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__strong_alias(__libc_thr_yield,sched_yield)
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int
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sched_yield(void)
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{
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pthread_t self, next;
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extern int pthread__started;
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if (pthread__started) {
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self = pthread__self();
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SDPRINTF(("(sched_yield %p) yielding\n", self));
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pthread_spinlock(self, &pthread__runqueue_lock);
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self->pt_state = PT_STATE_RUNNABLE;
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PTQ_INSERT_TAIL(&pthread__runqueue, self, pt_runq);
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/*
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* There will always be at least one thread on the runqueue,
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* because we just put ourselves there.
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*/
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next = PTQ_FIRST(&pthread__runqueue);
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PTQ_REMOVE(&pthread__runqueue, next, pt_runq);
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next->pt_state = PT_STATE_RUNNING;
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if (next != self)
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pthread__locked_switch(self, next,
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&pthread__runqueue_lock);
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else
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pthread_spinunlock(self, &pthread__runqueue_lock);
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}
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return 0;
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}
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/* Go do another thread, without putting us on the run queue. */
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void
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pthread__block(pthread_t self, pthread_spin_t *queuelock)
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{
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pthread_t next;
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next = pthread__next(self);
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next->pt_state = PT_STATE_RUNNING;
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SDPRINTF(("(calling locked_switch %p, %p) spinlock %d, %d\n",
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self, next, self->pt_spinlocks, next->pt_spinlocks));
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pthread__locked_switch(self, next, queuelock);
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SDPRINTF(("(back from locked_switch %p, %p) spinlock %d, %d\n",
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self, next, self->pt_spinlocks, next->pt_spinlocks));
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}
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/* Get the next thread to switch to. Will never return NULL. */
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pthread_t
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pthread__next(pthread_t self)
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{
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pthread_t next;
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pthread_spinlock(self, &pthread__runqueue_lock);
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next = PTQ_FIRST(&pthread__runqueue);
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if (next) {
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pthread__assert(next->pt_type == PT_THREAD_NORMAL);
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PTQ_REMOVE(&pthread__runqueue, next, pt_runq);
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} else {
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next = PTQ_FIRST(&pthread__idlequeue);
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pthread__assert(next != 0);
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PTQ_REMOVE(&pthread__idlequeue, next, pt_runq);
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pthread__assert(next->pt_type == PT_THREAD_IDLE);
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SDPRINTF(("(next %p) returning idle thread %p\n", self, next));
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}
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pthread_spinunlock(self, &pthread__runqueue_lock);
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return next;
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}
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/* Put a thread back on the run queue */
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void
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pthread__sched(pthread_t self, pthread_t thread)
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{
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SDPRINTF(("(sched %p) scheduling %p\n", self, thread));
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thread->pt_state = PT_STATE_RUNNABLE;
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pthread__assert (thread->pt_type == PT_THREAD_NORMAL);
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pthread__assert (thread->pt_spinlocks == 0);
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#ifdef PTHREAD__DEBUG
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thread->rescheds++;
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#endif
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pthread_spinlock(self, &pthread__runqueue_lock);
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PTQ_INSERT_TAIL(&pthread__runqueue, thread, pt_runq);
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pthread_spinunlock(self, &pthread__runqueue_lock);
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}
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/* Put a bunch of sleeping threads on the run queue */
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void
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pthread__sched_sleepers(pthread_t self, struct pthread_queue_t *threadq)
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{
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pthread_t thread;
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pthread_spinlock(self, &pthread__runqueue_lock);
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PTQ_FOREACH(thread, threadq, pt_sleep) {
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SDPRINTF(("(sched_sleepers %p) scheduling %p\n", self, thread));
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thread->pt_state = PT_STATE_RUNNABLE;
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pthread__assert (thread->pt_type == PT_THREAD_NORMAL);
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pthread__assert (thread->pt_spinlocks == 0);
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#ifdef PTHREAD__DEBUG
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thread->rescheds++;
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#endif
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PTQ_INSERT_TAIL(&pthread__runqueue, thread, pt_runq);
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}
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pthread_spinunlock(self, &pthread__runqueue_lock);
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}
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/* Make a thread a candidate idle thread. */
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void
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pthread__sched_idle(pthread_t self, pthread_t thread)
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{
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SDPRINTF(("(sched_idle %p) idling %p\n", self, thread));
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thread->pt_state = PT_STATE_RUNNABLE;
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thread->pt_flags &= ~PT_FLAG_IDLED;
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_INITCONTEXT_U(thread->pt_uc);
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thread->pt_uc->uc_stack = thread->pt_stack;
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thread->pt_uc->uc_link = NULL;
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makecontext(thread->pt_uc, pthread__idle, 0);
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pthread_spinlock(self, &pthread__runqueue_lock);
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PTQ_INSERT_TAIL(&pthread__idlequeue, thread, pt_runq);
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pthread_spinunlock(self, &pthread__runqueue_lock);
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}
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void
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pthread__sched_idle2(pthread_t self)
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{
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pthread_t idlethread, qhead, next;
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qhead = NULL;
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pthread_spinlock(self, &pthread__deadqueue_lock);
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idlethread = PTQ_FIRST(&pthread__reidlequeue);
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while (idlethread != NULL) {
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SDPRINTF(("(sched_idle2 %p) reidling %p\n", self, idlethread));
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next = PTQ_NEXT(idlethread, pt_runq);
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if (idlethread->pt_next == NULL) {
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PTQ_REMOVE(&pthread__reidlequeue, idlethread, pt_runq);
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idlethread->pt_next = qhead;
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qhead = idlethread;
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} else {
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SDPRINTF(("(sched_idle2 %p) %p is in a preemption loop\n", self, idlethread));
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}
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idlethread = next;
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}
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pthread_spinunlock(self, &pthread__deadqueue_lock);
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if (qhead)
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pthread__sched_bulk(self, qhead);
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}
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/*
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* Put a series of threads, linked by their pt_next fields, onto the
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* run queue.
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*/
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void
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pthread__sched_bulk(pthread_t self, pthread_t qhead)
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{
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pthread_t next;
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pthread_spinlock(self, &pthread__runqueue_lock);
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for ( ; qhead && (qhead != self) ; qhead = next) {
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next = qhead->pt_next;
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pthread__assert (qhead->pt_spinlocks == 0);
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if (qhead->pt_type == PT_THREAD_NORMAL) {
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qhead->pt_state = PT_STATE_RUNNABLE;
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qhead->pt_next = NULL;
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qhead->pt_parent = NULL;
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#ifdef PTHREAD__DEBUG
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qhead->rescheds++;
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#endif
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SDPRINTF(("(bulk %p) scheduling %p\n", self, qhead));
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pthread__assert(PTQ_LAST(&pthread__runqueue, pthread_queue_t) != qhead);
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pthread__assert(PTQ_FIRST(&pthread__runqueue) != qhead);
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PTQ_INSERT_TAIL(&pthread__runqueue, qhead, pt_runq);
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} else if (qhead->pt_type == PT_THREAD_IDLE) {
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qhead->pt_state = PT_STATE_RUNNABLE;
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qhead->pt_flags &= ~PT_FLAG_IDLED;
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qhead->pt_next = NULL;
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qhead->pt_parent = NULL;
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_INITCONTEXT_U(qhead->pt_uc);
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qhead->pt_uc->uc_stack = qhead->pt_stack;
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qhead->pt_uc->uc_link = NULL;
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makecontext(qhead->pt_uc, pthread__idle, 0);
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SDPRINTF(("(bulk %p) idling %p\n", self, qhead));
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PTQ_INSERT_TAIL(&pthread__idlequeue, qhead, pt_runq);
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}
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}
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pthread_spinunlock(self, &pthread__runqueue_lock);
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}
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