| #ifdef CONFIG_SCHED_AUTOGROUP |
| |
| #include <linux/proc_fs.h> |
| #include <linux/seq_file.h> |
| #include <linux/kallsyms.h> |
| #include <linux/utsname.h> |
| |
| unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1; |
| static struct autogroup autogroup_default; |
| static atomic_t autogroup_seq_nr; |
| |
| static void __init autogroup_init(struct task_struct *init_task) |
| { |
| autogroup_default.tg = &root_task_group; |
| root_task_group.autogroup = &autogroup_default; |
| kref_init(&autogroup_default.kref); |
| init_rwsem(&autogroup_default.lock); |
| init_task->signal->autogroup = &autogroup_default; |
| } |
| |
| static inline 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; |
| } |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| static void free_rt_sched_group(struct task_group *tg); |
| #endif |
| |
| 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); |
| } |
| |
| static inline 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 inline bool task_group_is_autogroup(struct task_group *tg) |
| { |
| return tg != &root_task_group && tg->autogroup; |
| } |
| |
| static inline struct task_group * |
| autogroup_task_group(struct task_struct *p, struct task_group *tg) |
| { |
| int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled); |
| |
| if (enabled && task_wants_autogroup(p, tg)) |
| return p->signal->autogroup->tg; |
| |
| return tg; |
| } |
| |
| static void |
| autogroup_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 refrence 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); |
| |
| down_read(&ag->lock); |
| seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice); |
| up_read(&ag->lock); |
| |
| autogroup_kref_put(ag); |
| } |
| #endif /* CONFIG_PROC_FS */ |
| |
| #ifdef CONFIG_SCHED_DEBUG |
| static inline int autogroup_path(struct task_group *tg, char *buf, int buflen) |
| { |
| int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled); |
| |
| if (!enabled || !tg->autogroup) |
| return 0; |
| |
| return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id); |
| } |
| #endif /* CONFIG_SCHED_DEBUG */ |
| |
| #endif /* CONFIG_SCHED_AUTOGROUP */ |