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