3 files changed, 137 insertions, 0 deletions

diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 651ff0869b2d..0b9bfbde8168 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -30,3 +30,9 @@ SUBSYS(ns)
 #endif
 
 /* */
+
+#ifdef CONFIG_FAIR_CGROUP_SCHED
+SUBSYS(cpu_cgroup)
+#endif
+
+/* */
diff --git a/init/Kconfig b/init/Kconfig
index 0007d1b5e867..541382d539ad 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -334,6 +334,16 @@ config FAIR_USER_SCHED
           This option will choose userid as the basis for grouping
           tasks, thus providing equal CPU bandwidth to each user.
 
+config FAIR_CGROUP_SCHED
+        bool "Control groups"
+        depends on CGROUPS
+        help
+          This option allows you to create arbitrary task groups
+          using the "cgroup" pseudo filesystem and control
+          the cpu bandwidth allocated to each such task group.
+          Refer to Documentation/cgroups.txt for more information
+          on "cgroup" pseudo filesystem.
+
 endchoice
 
 config SYSFS_DEPRECATED
diff --git a/kernel/sched.c b/kernel/sched.c
index 4071306e1088..afe76ec2e7fe 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -155,10 +155,15 @@ struct rt_prio_array {
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 
+#include <linux/cgroup.h>
+
 struct cfs_rq;
 
 /* task group related information */
 struct task_group {
+#ifdef CONFIG_FAIR_CGROUP_SCHED
+        struct cgroup_subsys_state css;
+#endif
         /* schedulable entities of this group on each cpu */
         struct sched_entity **se;
         /* runqueue "owned" by this group on each cpu */
@@ -199,6 +204,9 @@ static inline struct task_group *task_group(struct task_struct *p)
 
 #ifdef CONFIG_FAIR_USER_SCHED
         tg = p->user->tg;
+#elif defined(CONFIG_FAIR_CGROUP_SCHED)
+        tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
+                                struct task_group, css);
 #else
         tg  = &init_task_group;
 #endif
@@ -7091,3 +7099,116 @@ unsigned long sched_group_shares(struct task_group *tg)
 }
 
 #endif  /* CONFIG_FAIR_GROUP_SCHED */
+
+#ifdef CONFIG_FAIR_CGROUP_SCHED
+
+/* return corresponding task_group object of a cgroup */
+static inline struct task_group *cgroup_tg(struct cgroup *cont)
+{
+        return container_of(cgroup_subsys_state(cont, cpu_cgroup_subsys_id),
+                                         struct task_group, css);
+}
+
+static struct cgroup_subsys_state *
+cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+        struct task_group *tg;
+
+        if (!cont->parent) {
+                /* This is early initialization for the top cgroup */
+                init_task_group.css.cgroup = cont;
+                return &init_task_group.css;
+        }
+
+        /* we support only 1-level deep hierarchical scheduler atm */
+        if (cont->parent->parent)
+                return ERR_PTR(-EINVAL);
+
+        tg = sched_create_group();
+        if (IS_ERR(tg))
+                return ERR_PTR(-ENOMEM);
+
+        /* Bind the cgroup to task_group object we just created */
+        tg->css.cgroup = cont;
+
+        return &tg->css;
+}
+
+static void cpu_cgroup_destroy(struct cgroup_subsys *ss,
+                                        struct cgroup *cont)
+{
+        struct task_group *tg = cgroup_tg(cont);
+
+        sched_destroy_group(tg);
+}
+
+static int cpu_cgroup_can_attach(struct cgroup_subsys *ss,
+                             struct cgroup *cont, struct task_struct *tsk)
+{
+        /* We don't support RT-tasks being in separate groups */
+        if (tsk->sched_class != &fair_sched_class)
+                return -EINVAL;
+
+        return 0;
+}
+
+static void
+cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cont,
+                        struct cgroup *old_cont, struct task_struct *tsk)
+{
+        sched_move_task(tsk);
+}
+
+static ssize_t cpu_shares_write(struct cgroup *cont, struct cftype *cftype,
+                                struct file *file, const char __user *userbuf,
+                                size_t nbytes, loff_t *ppos)
+{
+        unsigned long shareval;
+        struct task_group *tg = cgroup_tg(cont);
+        char buffer[2*sizeof(unsigned long) + 1];
+        int rc;
+
+        if (nbytes > 2*sizeof(unsigned long))   /* safety check */
+                return -E2BIG;
+
+        if (copy_from_user(buffer, userbuf, nbytes))
+                return -EFAULT;
+
+        buffer[nbytes] = 0;     /* nul-terminate */
+        shareval = simple_strtoul(buffer, NULL, 10);
+
+        rc = sched_group_set_shares(tg, shareval);
+
+        return (rc < 0 ? rc : nbytes);
+}
+
+static u64 cpu_shares_read_uint(struct cgroup *cont, struct cftype *cft)
+{
+        struct task_group *tg = cgroup_tg(cont);
+
+        return (u64) tg->shares;
+}
+
+static struct cftype cpu_shares = {
+        .name = "shares",
+        .read_uint = cpu_shares_read_uint,
+        .write = cpu_shares_write,
+};
+
+static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
+{
+        return cgroup_add_file(cont, ss, &cpu_shares);
+}
+
+struct cgroup_subsys cpu_cgroup_subsys = {
+        .name           = "cpu",
+        .create         = cpu_cgroup_create,
+        .destroy        = cpu_cgroup_destroy,
+        .can_attach     = cpu_cgroup_can_attach,
+        .attach         = cpu_cgroup_attach,
+        .populate       = cpu_cgroup_populate,
+        .subsys_id      = cpu_cgroup_subsys_id,
+        .early_init     = 1,
+};
+
+#endif  /* CONFIG_FAIR_CGROUP_SCHED */