7 files changed, 292 insertions, 49 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 3b159c5991b7..b6f2475f1e83 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -174,8 +174,10 @@ static inline void free_signal_struct(struct signal_struct *sig)
 
 static inline void put_signal_struct(struct signal_struct *sig)
 {
-        if (atomic_dec_and_test(&sig->sigcnt))
+        if (atomic_dec_and_test(&sig->sigcnt)) {
+                sched_autogroup_exit(sig);
                 free_signal_struct(sig);
+        }
 }
 
 void __put_task_struct(struct task_struct *tsk)
@@ -904,6 +906,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
         posix_cpu_timers_init_group(sig);
 
         tty_audit_fork(sig);
+        sched_autogroup_fork(sig);
 
         sig->oom_adj = current->signal->oom_adj;
         sig->oom_score_adj = current->signal->oom_score_adj;
diff --git a/kernel/sched.c b/kernel/sched.c
index 66ef5790d932..b646dad4a40e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -79,6 +79,7 @@
 
 #include "sched_cpupri.h"
 #include "workqueue_sched.h"
+#include "sched_autogroup.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
@@ -271,6 +272,10 @@ struct task_group {
         struct task_group *parent;
         struct list_head siblings;
         struct list_head children;
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+        struct autogroup *autogroup;
+#endif
 };
 
 #define root_task_group init_task_group
@@ -603,11 +608,14 @@ static inline int cpu_of(struct rq *rq)
  */
 static inline struct task_group *task_group(struct task_struct *p)
 {
+        struct task_group *tg;
         struct cgroup_subsys_state *css;
 
         css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
                         lockdep_is_held(&task_rq(p)->lock));
-        return container_of(css, struct task_group, css);
+        tg = container_of(css, struct task_group, css);
+
+        return autogroup_task_group(p, tg);
 }
 
 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
@@ -1869,6 +1877,7 @@ static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) { }
 #include "sched_idletask.c"
 #include "sched_fair.c"
 #include "sched_rt.c"
+#include "sched_autogroup.c"
 #include "sched_stoptask.c"
 #ifdef CONFIG_SCHED_DEBUG
 # include "sched_debug.c"
@@ -7750,7 +7759,7 @@ void __init sched_init(void)
 #ifdef CONFIG_CGROUP_SCHED
         list_add(&init_task_group.list, &task_groups);
         INIT_LIST_HEAD(&init_task_group.children);
-
+        autogroup_init(&init_task);
 #endif /* CONFIG_CGROUP_SCHED */
 
         for_each_possible_cpu(i) {
diff --git a/kernel/sched_autogroup.c b/kernel/sched_autogroup.c
new file mode 100644
index 000000000000..57a7ac286a02
--- /dev/null
+++ b/kernel/sched_autogroup.c
@@ -0,0 +1,229 @@
+#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 autogroup_init(struct task_struct *init_task)
+{
+        autogroup_default.tg = &init_task_group;
+        init_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);
+
+        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_create(void)
+{
+        struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
+        struct task_group *tg;
+
+        if (!ag)
+                goto out_fail;
+
+        tg = sched_create_group(&init_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;
+        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 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