#ifdef CONFIG_SCHED_AUTOGROUP #include "sched.h" #include <linux/proc_fs.h>#include <linux/seq_file.h>#include <linux/kallsyms.h>#include <linux/utsname.h>#include <linux/security.h>#include <linux/export.h> unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;static struct autogroup autogroup_default;static atomic_t autogroup_seq_nr; void __init autogroup_init(struct task_struct *init_task){	autogroup_default.tg = &root_task_group;	kref_init(&autogroup_default.kref);	init_rwsem(&autogroup_default.lock);	init_task->signal->autogroup = &autogroup_default;} void autogroup_free(struct task_group *tg){	kfree(tg->autogroup);} static inline void autogroup_destroy(struct kref *kref){	struct autogroup *ag = container_of(kref, struct autogroup, kref); #ifdef CONFIG_RT_GROUP_SCHED	/* We've redirected RT tasks to the root task group... */	ag->tg->rt_se = NULL;	ag->tg->rt_rq = NULL;#endif	sched_destroy_group(ag->tg);} static inline void autogroup_kref_put(struct autogroup *ag){	kref_put(&ag->kref, autogroup_destroy);} static inline struct autogroup *autogroup_kref_get(struct autogroup *ag){	kref_get(&ag->kref);	return ag;} static inline struct autogroup *autogroup_task_get(struct task_struct *p){	struct autogroup *ag;	unsigned long flags; 	if (!lock_task_sighand(p, &flags))		return autogroup_kref_get(&autogroup_default); 	ag = autogroup_kref_get(p->signal->autogroup);	unlock_task_sighand(p, &flags); 	return ag;} static inline struct autogroup *autogroup_create(void){	struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);	struct task_group *tg; 	if (!ag)		goto out_fail; 	tg = sched_create_group(&root_task_group); 	if (IS_ERR(tg))		goto out_free; 	kref_init(&ag->kref);	init_rwsem(&ag->lock);	ag->id = atomic_inc_return(&autogroup_seq_nr);	ag->tg = tg;#ifdef CONFIG_RT_GROUP_SCHED	/*	 * Autogroup RT tasks are redirected to the root task group	 * so we don't have to move tasks around upon policy change,	 * or flail around trying to allocate bandwidth on the fly.	 * A bandwidth exception in __sched_setscheduler() allows	 * the policy change to proceed.  Thereafter, task_group()	 * returns &root_task_group, so zero bandwidth is required.	 */	free_rt_sched_group(tg);	tg->rt_se = root_task_group.rt_se;	tg->rt_rq = root_task_group.rt_rq;#endif	tg->autogroup = ag; 	return ag; out_free:	kfree(ag);out_fail:	if (printk_ratelimit()) {		printk(KERN_WARNING "autogroup_create: %s failure.\n",			ag ? "sched_create_group()" : "kmalloc()");	} 	return autogroup_kref_get(&autogroup_default);} bool task_wants_autogroup(struct task_struct *p, struct task_group *tg){	if (tg != &root_task_group)		return false; 	if (p->sched_class != &fair_sched_class)		return false; 	/*	 * We can only assume the task group can't go away on us if	 * autogroup_move_group() can see us on ->thread_group list.	 */	if (p->flags & PF_EXITING)		return false; 	return true;} static voidautogroup_move_group(struct task_struct *p, struct autogroup *ag){	struct autogroup *prev;	struct task_struct *t;	unsigned long flags; 	BUG_ON(!lock_task_sighand(p, &flags)); 	prev = p->signal->autogroup;	if (prev == ag) {		unlock_task_sighand(p, &flags);		return;	} 	p->signal->autogroup = autogroup_kref_get(ag); 	if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))		goto out; 	t = p;	do {		sched_move_task(t);	} while_each_thread(p, t); out:	unlock_task_sighand(p, &flags);	autogroup_kref_put(prev);} /* Allocates GFP_KERNEL, cannot be called under any spinlock */void sched_autogroup_create_attach(struct task_struct *p){	struct autogroup *ag = autogroup_create(); 	autogroup_move_group(p, ag);	/* drop extra reference added by autogroup_create() */	autogroup_kref_put(ag);}EXPORT_SYMBOL(sched_autogroup_create_attach); /* Cannot be called under siglock.  Currently has no users */void sched_autogroup_detach(struct task_struct *p){	autogroup_move_group(p, &autogroup_default);}EXPORT_SYMBOL(sched_autogroup_detach); void sched_autogroup_fork(struct signal_struct *sig){	sig->autogroup = autogroup_task_get(current);} void sched_autogroup_exit(struct signal_struct *sig){	autogroup_kref_put(sig->autogroup);} static int __init setup_autogroup(char *str){	sysctl_sched_autogroup_enabled = 0; 	return 1;} __setup("noautogroup", setup_autogroup); #ifdef CONFIG_PROC_FS int proc_sched_autogroup_set_nice(struct task_struct *p, int nice){	static unsigned long next = INITIAL_JIFFIES;	struct autogroup *ag;	int err; 	if (nice < -20 || nice > 19)		return -EINVAL; 	err = security_task_setnice(current, nice);	if (err)		return err; 	if (nice < 0 && !can_nice(current, nice))		return -EPERM; 	/* this is a heavy operation taking global locks.. */	if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))		return -EAGAIN; 	next = HZ / 10 + jiffies;	ag = autogroup_task_get(p); 	down_write(&ag->lock);	err = sched_group_set_shares(ag->tg, prio_to_weight[nice + 20]);	if (!err)		ag->nice = nice;	up_write(&ag->lock); 	autogroup_kref_put(ag); 	return err;} void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m){	struct autogroup *ag = autogroup_task_get(p); 	if (!task_group_is_autogroup(ag->tg))		goto out; 	down_read(&ag->lock);	seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);	up_read(&ag->lock); out:	autogroup_kref_put(ag);}#endif /* CONFIG_PROC_FS */ #ifdef CONFIG_SCHED_DEBUGint autogroup_path(struct task_group *tg, char *buf, int buflen){	if (!task_group_is_autogroup(tg))		return 0; 	return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);}#endif /* CONFIG_SCHED_DEBUG */ #endif /* CONFIG_SCHED_AUTOGROUP */