--- /dev/null
+#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_offline_group(ag->tg);
+ 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.
+ */
+ 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;
+
+ sched_online_group(tg, &root_task_group);
+ 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;
+
+ /*
+ * 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 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;
+
+ for_each_thread(p, t)
+ sched_move_task(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 < MIN_NICE || nice > MAX_NICE)
+ 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_DEBUG
+int 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 */
Code Review / kvmfornfv.git / blobdiff