4 files changed, 258 insertions, 1 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
new file mode 100644
index 000000000000..60735dcf427a
--- /dev/null
+++ b/include/linux/cgroup.h
@@ -0,0 +1,214 @@
+#ifndef _LINUX_CGROUP_H
+#define _LINUX_CGROUP_H
+/*
+ *  cgroup interface
+ *
+ *  Copyright (C) 2003 BULL SA
+ *  Copyright (C) 2004-2006 Silicon Graphics, Inc.
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/kref.h>
+#include <linux/cpumask.h>
+#include <linux/nodemask.h>
+#include <linux/rcupdate.h>
+
+#ifdef CONFIG_CGROUPS
+
+struct cgroupfs_root;
+struct cgroup_subsys;
+struct inode;
+
+extern int cgroup_init_early(void);
+extern int cgroup_init(void);
+extern void cgroup_init_smp(void);
+extern void cgroup_lock(void);
+extern void cgroup_unlock(void);
+
+/* Per-subsystem/per-cgroup state maintained by the system. */
+struct cgroup_subsys_state {
+        /* The cgroup that this subsystem is attached to. Useful
+         * for subsystems that want to know about the cgroup
+         * hierarchy structure */
+        struct cgroup *cgroup;
+
+        /* State maintained by the cgroup system to allow
+         * subsystems to be "busy". Should be accessed via css_get()
+         * and css_put() */
+
+        atomic_t refcnt;
+
+        unsigned long flags;
+};
+
+/* bits in struct cgroup_subsys_state flags field */
+enum {
+        CSS_ROOT, /* This CSS is the root of the subsystem */
+};
+
+/*
+ * Call css_get() to hold a reference on the cgroup;
+ *
+ */
+
+static inline void css_get(struct cgroup_subsys_state *css)
+{
+        /* We don't need to reference count the root state */
+        if (!test_bit(CSS_ROOT, &css->flags))
+                atomic_inc(&css->refcnt);
+}
+/*
+ * css_put() should be called to release a reference taken by
+ * css_get()
+ */
+
+static inline void css_put(struct cgroup_subsys_state *css)
+{
+        if (!test_bit(CSS_ROOT, &css->flags))
+                atomic_dec(&css->refcnt);
+}
+
+struct cgroup {
+        unsigned long flags;            /* "unsigned long" so bitops work */
+
+        /* count users of this cgroup. >0 means busy, but doesn't
+         * necessarily indicate the number of tasks in the
+         * cgroup */
+        atomic_t count;
+
+        /*
+         * We link our 'sibling' struct into our parent's 'children'.
+         * Our children link their 'sibling' into our 'children'.
+         */
+        struct list_head sibling;       /* my parent's children */
+        struct list_head children;      /* my children */
+
+        struct cgroup *parent;  /* my parent */
+        struct dentry *dentry;          /* cgroup fs entry */
+
+        /* Private pointers for each registered subsystem */
+        struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
+
+        struct cgroupfs_root *root;
+        struct cgroup *top_cgroup;
+};
+
+/* struct cftype:
+ *
+ * The files in the cgroup filesystem mostly have a very simple read/write
+ * handling, some common function will take care of it. Nevertheless some cases
+ * (read tasks) are special and therefore I define this structure for every
+ * kind of file.
+ *
+ *
+ * When reading/writing to a file:
+ *      - the cgroup to use in file->f_dentry->d_parent->d_fsdata
+ *      - the 'cftype' of the file is file->f_dentry->d_fsdata
+ */
+
+#define MAX_CFTYPE_NAME 64
+struct cftype {
+        /* By convention, the name should begin with the name of the
+         * subsystem, followed by a period */
+        char name[MAX_CFTYPE_NAME];
+        int private;
+        int (*open) (struct inode *inode, struct file *file);
+        ssize_t (*read) (struct cgroup *cont, struct cftype *cft,
+                         struct file *file,
+                         char __user *buf, size_t nbytes, loff_t *ppos);
+        /*
+         * read_uint() is a shortcut for the common case of returning a
+         * single integer. Use it in place of read()
+         */
+        u64 (*read_uint) (struct cgroup *cont, struct cftype *cft);
+        ssize_t (*write) (struct cgroup *cont, struct cftype *cft,
+                          struct file *file,
+                          const char __user *buf, size_t nbytes, loff_t *ppos);
+        int (*release) (struct inode *inode, struct file *file);
+};
+
+/* Add a new file to the given cgroup directory. Should only be
+ * called by subsystems from within a populate() method */
+int cgroup_add_file(struct cgroup *cont, struct cgroup_subsys *subsys,
+                       const struct cftype *cft);
+
+/* Add a set of new files to the given cgroup directory. Should
+ * only be called by subsystems from within a populate() method */
+int cgroup_add_files(struct cgroup *cont,
+                        struct cgroup_subsys *subsys,
+                        const struct cftype cft[],
+                        int count);
+
+int cgroup_is_removed(const struct cgroup *cont);
+
+int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
+
+/* Return true if the cgroup is a descendant of the current cgroup */
+int cgroup_is_descendant(const struct cgroup *cont);
+
+/* Control Group subsystem type. See Documentation/cgroups.txt for details */
+
+struct cgroup_subsys {
+        struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
+                                                  struct cgroup *cont);
+        void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cont);
+        int (*can_attach)(struct cgroup_subsys *ss,
+                          struct cgroup *cont, struct task_struct *tsk);
+        void (*attach)(struct cgroup_subsys *ss, struct cgroup *cont,
+                        struct cgroup *old_cont, struct task_struct *tsk);
+        void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
+        void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
+        int (*populate)(struct cgroup_subsys *ss,
+                        struct cgroup *cont);
+        void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
+        int subsys_id;
+        int active;
+        int early_init;
+#define MAX_CGROUP_TYPE_NAMELEN 32
+        const char *name;
+
+        /* Protected by RCU */
+        struct cgroupfs_root *root;
+
+        struct list_head sibling;
+
+        void *private;
+};
+
+#define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys;
+#include <linux/cgroup_subsys.h>
+#undef SUBSYS
+
+static inline struct cgroup_subsys_state *cgroup_subsys_state(
+        struct cgroup *cont, int subsys_id)
+{
+        return cont->subsys[subsys_id];
+}
+
+static inline struct cgroup_subsys_state *task_subsys_state(
+        struct task_struct *task, int subsys_id)
+{
+        return rcu_dereference(task->cgroups.subsys[subsys_id]);
+}
+
+static inline struct cgroup* task_cgroup(struct task_struct *task,
+                                               int subsys_id)
+{
+        return task_subsys_state(task, subsys_id)->cgroup;
+}
+
+int cgroup_path(const struct cgroup *cont, char *buf, int buflen);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline int cgroup_init_early(void) { return 0; }
+static inline int cgroup_init(void) { return 0; }
+static inline void cgroup_init_smp(void) {}
+
+static inline void cgroup_lock(void) {}
+static inline void cgroup_unlock(void) {}
+
+#endif /* !CONFIG_CGROUPS */
+
+#endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
new file mode 100644
index 000000000000..f8eddbbcad9a
--- /dev/null
+++ b/include/linux/cgroup_subsys.h
@@ -0,0 +1,10 @@
+/* Add subsystem definitions of the form SUBSYS(<name>) in this
+ * file. Surround each one by a line of comment markers so that
+ * patches don't collide
+ */
+
+/* */
+
+/* */
+
+/* */
diff --git a/include/linux/magic.h b/include/linux/magic.h
index 722d4755060f..1fa0c2ce4dec 100644
--- a/include/linux/magic.h
+++ b/include/linux/magic.h
@@ -37,6 +37,7 @@
 
 #define SMB_SUPER_MAGIC         0x517B
 #define USBDEVICE_SUPER_MAGIC   0x9fa2
+#define CGROUP_SUPER_MAGIC      0x27e0eb
 
 #define FUTEXFS_SUPER_MAGIC     0xBAD1DEA
 #define INOTIFYFS_SUPER_MAGIC   0x2BAD1DEA
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 10a83d8d5775..af2ed4bae678 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -894,6 +894,34 @@ struct sched_entity {
 #endif
 };
 
+#ifdef CONFIG_CGROUPS
+
+#define SUBSYS(_x) _x ## _subsys_id,
+enum cgroup_subsys_id {
+#include <linux/cgroup_subsys.h>
+        CGROUP_SUBSYS_COUNT
+};
+#undef SUBSYS
+
+/* A css_set is a structure holding pointers to a set of
+ * cgroup_subsys_state objects.
+ */
+
+struct css_set {
+
+        /* Set of subsystem states, one for each subsystem. NULL for
+         * subsystems that aren't part of this hierarchy. These
+         * pointers reduce the number of dereferences required to get
+         * from a task to its state for a given cgroup, but result
+         * in increased space usage if tasks are in wildly different
+         * groupings across different hierarchies. This array is
+         * immutable after creation */
+        struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
+
+};
+
+#endif /* CONFIG_CGROUPS */
+
 struct task_struct {
         volatile long state;    /* -1 unrunnable, 0 runnable, >0 stopped */
         void *stack;
@@ -1130,6 +1158,9 @@ struct task_struct {
         int cpuset_mems_generation;
         int cpuset_mem_spread_rotor;
 #endif
+#ifdef CONFIG_CGROUPS
+        struct css_set cgroups;
+#endif
 #ifdef CONFIG_FUTEX
         struct robust_list_head __user *robust_list;
 #ifdef CONFIG_COMPAT
@@ -1625,7 +1656,8 @@ static inline int thread_group_empty(struct task_struct *p)
 /*
  * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
  * subscriptions and synchronises with wait4().  Also used in procfs.  Also
- * pins the final release of task.io_context.  Also protects ->cpuset.
+ * pins the final release of task.io_context.  Also protects ->cpuset and
+ * ->cgroup.subsys[].
  *
  * Nests both inside and outside of read_lock(&tasklist_lock).
  * It must not be nested with write_lock_irq(&tasklist_lock),