#include <u.h>#include <libc.h>#include <thread.h>#include "threadimpl.h" Pqueue _threadpq; static intnextID(void){	static Lock l;	static int id;	int i; 	lock(&l);	i = ++id;	unlock(&l);	return i;}	/* * Create and initialize a new Thread structure attached to a given proc. */static intnewthread(Proc *p, void (*f)(void *arg), void *arg, uint stacksize, char *name, int grp){	int id;	Thread *t; 	if(stacksize < 32)		sysfatal("bad stacksize %d", stacksize);	t = _threadmalloc(sizeof(Thread), 1);	t->stksize = stacksize;	t->stk = _threadmalloc(stacksize, 0);	memset(t->stk, 0xFE, stacksize);	_threadinitstack(t, f, arg);	t->grp = grp;	if(name)		t->cmdname = strdup(name);	t->id = nextID();	id = t->id;	t->next = (Thread*)~0;	t->proc = p;	_threaddebug(DBGSCHED, "create thread %d.%d name %s", p->pid, t->id, name);	lock(&p->lock);	p->nthreads++;	if(p->threads.head == nil)		p->threads.head = t;	else		*p->threads.tail = t;	p->threads.tail = &t->nextt;	t->nextt = nil;	t->state = Ready;	_threadready(t);	unlock(&p->lock);	return id;} /*  * Create a new thread and schedule it to run. * The thread grp is inherited from the currently running thread. */intthreadcreate(void (*f)(void *arg), void *arg, uint stacksize){	return newthread(_threadgetproc(), f, arg, stacksize, nil, threadgetgrp());} /* * Create and initialize a new Proc structure with a single Thread * running inside it.  Add the Proc to the global process list. */Proc*_newproc(void (*f)(void *arg), void *arg, uint stacksize, char *name, int grp, int rforkflag){	Proc *p; 	p = _threadmalloc(sizeof *p, 1);	p->pid = -1;	p->rforkflag = rforkflag;	newthread(p, f, arg, stacksize, name, grp); 	lock(&_threadpq.lock);	if(_threadpq.head == nil)		_threadpq.head = p;	else		*_threadpq.tail = p;	_threadpq.tail = &p->next;	unlock(&_threadpq.lock);	return p;} intprocrfork(void (*f)(void *), void *arg, uint stacksize, int rforkflag){	Proc *p;	int id; 	p = _threadgetproc();	while(p->newproc)		_sched();	p->newproc = _newproc(f, arg, stacksize, nil, p->thread->grp, rforkflag);	id = p->newproc->threads.head->id;	_sched();	return id;} intproccreate(void (*f)(void*), void *arg, uint stacksize){	return procrfork(f, arg, stacksize, 0);}