--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/include/linux/cgroup.h Sun Jan 11 20:20:11 2009 +0100
@@ -0,0 +1,428 @@
+#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/cpumask.h>
+#include <linux/nodemask.h>
+#include <linux/rcupdate.h>
+#include <linux/cgroupstats.h>
+#include <linux/prio_heap.h>
+#include <linux/rwsem.h>
+
+#ifdef CONFIG_CGROUPS
+
+struct cgroupfs_root;
+struct cgroup_subsys;
+struct inode;
+struct cgroup;
+
+extern int cgroup_init_early(void);
+extern int cgroup_init(void);
+extern void cgroup_lock(void);
+extern bool cgroup_lock_live_group(struct cgroup *cgrp);
+extern void cgroup_unlock(void);
+extern void cgroup_fork(struct task_struct *p);
+extern void cgroup_fork_callbacks(struct task_struct *p);
+extern void cgroup_post_fork(struct task_struct *p);
+extern void cgroup_exit(struct task_struct *p, int run_callbacks);
+extern int cgroupstats_build(struct cgroupstats *stats,
+ struct dentry *dentry);
+
+extern struct file_operations proc_cgroup_operations;
+
+/* Define the enumeration of all cgroup subsystems */
+#define SUBSYS(_x) _x ## _subsys_id,
+enum cgroup_subsys_id {
+#include <linux/cgroup_subsys.h>
+ CGROUP_SUBSYS_COUNT
+};
+#undef SUBSYS
+
+/* 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()
+ */
+
+extern void __css_put(struct cgroup_subsys_state *css);
+static inline void css_put(struct cgroup_subsys_state *css)
+{
+ if (!test_bit(CSS_ROOT, &css->flags))
+ __css_put(css);
+}
+
+/* bits in struct cgroup flags field */
+enum {
+ /* Control Group is dead */
+ CGRP_REMOVED,
+ /* Control Group has previously had a child cgroup or a task,
+ * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set) */
+ CGRP_RELEASABLE,
+ /* Control Group requires release notifications to userspace */
+ CGRP_NOTIFY_ON_RELEASE,
+};
+
+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;
+
+ /*
+ * List of cg_cgroup_links pointing at css_sets with
+ * tasks in this cgroup. Protected by css_set_lock
+ */
+ struct list_head css_sets;
+
+ /*
+ * Linked list running through all cgroups that can
+ * potentially be reaped by the release agent. Protected by
+ * release_list_lock
+ */
+ struct list_head release_list;
+
+ /* pids_mutex protects the fields below */
+ struct rw_semaphore pids_mutex;
+ /* Array of process ids in the cgroup */
+ pid_t *tasks_pids;
+ /* How many files are using the current tasks_pids array */
+ int pids_use_count;
+ /* Length of the current tasks_pids array */
+ int pids_length;
+};
+
+/* A css_set is a structure holding pointers to a set of
+ * cgroup_subsys_state objects. This saves space in the task struct
+ * object and speeds up fork()/exit(), since a single inc/dec and a
+ * list_add()/del() can bump the reference count on the entire
+ * cgroup set for a task.
+ */
+
+struct css_set {
+
+ /* Reference count */
+ atomic_t refcount;
+
+ /*
+ * List running through all cgroup groups in the same hash
+ * slot. Protected by css_set_lock
+ */
+ struct hlist_node hlist;
+
+ /*
+ * List running through all tasks using this cgroup
+ * group. Protected by css_set_lock
+ */
+ struct list_head tasks;
+
+ /*
+ * List of cg_cgroup_link objects on link chains from
+ * cgroups referenced from this css_set. Protected by
+ * css_set_lock
+ */
+ struct list_head cg_links;
+
+ /*
+ * Set of subsystem states, one for each subsystem. This array
+ * is immutable after creation apart from the init_css_set
+ * during subsystem registration (at boot time).
+ */
+ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
+};
+
+/*
+ * cgroup_map_cb is an abstract callback API for reporting map-valued
+ * control files
+ */
+
+struct cgroup_map_cb {
+ int (*fill)(struct cgroup_map_cb *cb, const char *key, u64 value);
+ void *state;
+};
+
+/* 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 is 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;
+
+ /*
+ * If non-zero, defines the maximum length of string that can
+ * be passed to write_string; defaults to 64
+ */
+ size_t max_write_len;
+
+ int (*open)(struct inode *inode, struct file *file);
+ ssize_t (*read)(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ char __user *buf, size_t nbytes, loff_t *ppos);
+ /*
+ * read_u64() is a shortcut for the common case of returning a
+ * single integer. Use it in place of read()
+ */
+ u64 (*read_u64)(struct cgroup *cgrp, struct cftype *cft);
+ /*
+ * read_s64() is a signed version of read_u64()
+ */
+ s64 (*read_s64)(struct cgroup *cgrp, struct cftype *cft);
+ /*
+ * read_map() is used for defining a map of key/value
+ * pairs. It should call cb->fill(cb, key, value) for each
+ * entry. The key/value pairs (and their ordering) should not
+ * change between reboots.
+ */
+ int (*read_map)(struct cgroup *cont, struct cftype *cft,
+ struct cgroup_map_cb *cb);
+ /*
+ * read_seq_string() is used for outputting a simple sequence
+ * using seqfile.
+ */
+ int (*read_seq_string)(struct cgroup *cont, struct cftype *cft,
+ struct seq_file *m);
+
+ ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ const char __user *buf, size_t nbytes, loff_t *ppos);
+
+ /*
+ * write_u64() is a shortcut for the common case of accepting
+ * a single integer (as parsed by simple_strtoull) from
+ * userspace. Use in place of write(); return 0 or error.
+ */
+ int (*write_u64)(struct cgroup *cgrp, struct cftype *cft, u64 val);
+ /*
+ * write_s64() is a signed version of write_u64()
+ */
+ int (*write_s64)(struct cgroup *cgrp, struct cftype *cft, s64 val);
+
+ /*
+ * write_string() is passed a nul-terminated kernelspace
+ * buffer of maximum length determined by max_write_len.
+ * Returns 0 or -ve error code.
+ */
+ int (*write_string)(struct cgroup *cgrp, struct cftype *cft,
+ const char *buffer);
+ /*
+ * trigger() callback can be used to get some kick from the
+ * userspace, when the actual string written is not important
+ * at all. The private field can be used to determine the
+ * kick type for multiplexing.
+ */
+ int (*trigger)(struct cgroup *cgrp, unsigned int event);
+
+ int (*release)(struct inode *inode, struct file *file);
+};
+
+struct cgroup_scanner {
+ struct cgroup *cg;
+ int (*test_task)(struct task_struct *p, struct cgroup_scanner *scan);
+ void (*process_task)(struct task_struct *p,
+ struct cgroup_scanner *scan);
+ struct ptr_heap *heap;
+};
+
+/* 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 *cgrp, 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 *cgrp,
+ struct cgroup_subsys *subsys,
+ const struct cftype cft[],
+ int count);
+
+int cgroup_is_removed(const struct cgroup *cgrp);
+
+int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
+
+int cgroup_task_count(const struct cgroup *cgrp);
+
+/* Return true if the cgroup is a descendant of the current cgroup */
+int cgroup_is_descendant(const struct cgroup *cgrp);
+
+/* Control Group subsystem type. See Documentation/cgroups.txt for details */
+
+struct cgroup_subsys {
+ struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
+ struct cgroup *cgrp);
+ void (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
+ void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
+ int (*can_attach)(struct cgroup_subsys *ss,
+ struct cgroup *cgrp, struct task_struct *tsk);
+ void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
+ struct cgroup *old_cgrp, 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 *cgrp);
+ void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp);
+ void (*bind)(struct cgroup_subsys *ss, struct cgroup *root);
+ /*
+ * This routine is called with the task_lock of mm->owner held
+ */
+ void (*mm_owner_changed)(struct cgroup_subsys *ss,
+ struct cgroup *old,
+ struct cgroup *new,
+ struct task_struct *p);
+ int subsys_id;
+ int active;
+ int disabled;
+ int early_init;
+#define MAX_CGROUP_TYPE_NAMELEN 32
+ const char *name;
+
+ /* Protected by RCU */
+ struct cgroupfs_root *root;
+
+ struct list_head sibling;
+};
+
+#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 *cgrp, int subsys_id)
+{
+ return cgrp->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_clone(struct task_struct *tsk, struct cgroup_subsys *ss,
+ char *nodename);
+
+/* A cgroup_iter should be treated as an opaque object */
+struct cgroup_iter {
+ struct list_head *cg_link;
+ struct list_head *task;
+};
+
+/* To iterate across the tasks in a cgroup:
+ *
+ * 1) call cgroup_iter_start to intialize an iterator
+ *
+ * 2) call cgroup_iter_next() to retrieve member tasks until it
+ * returns NULL or until you want to end the iteration
+ *
+ * 3) call cgroup_iter_end() to destroy the iterator.
+ *
+ * Or, call cgroup_scan_tasks() to iterate through every task in a cpuset.
+ * - cgroup_scan_tasks() holds the css_set_lock when calling the test_task()
+ * callback, but not while calling the process_task() callback.
+ */
+void cgroup_iter_start(struct cgroup *cgrp, struct cgroup_iter *it);
+struct task_struct *cgroup_iter_next(struct cgroup *cgrp,
+ struct cgroup_iter *it);
+void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it);
+int cgroup_scan_tasks(struct cgroup_scanner *scan);
+int cgroup_attach_task(struct cgroup *, struct task_struct *);
+
+void cgroup_mm_owner_callbacks(struct task_struct *old,
+ struct task_struct *new);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline int cgroup_init_early(void) { return 0; }
+static inline int cgroup_init(void) { return 0; }
+static inline void cgroup_fork(struct task_struct *p) {}
+static inline void cgroup_fork_callbacks(struct task_struct *p) {}
+static inline void cgroup_post_fork(struct task_struct *p) {}
+static inline void cgroup_exit(struct task_struct *p, int callbacks) {}
+
+static inline void cgroup_lock(void) {}
+static inline void cgroup_unlock(void) {}
+static inline int cgroupstats_build(struct cgroupstats *stats,
+ struct dentry *dentry)
+{
+ return -EINVAL;
+}
+
+static inline void cgroup_mm_owner_callbacks(struct task_struct *old,
+ struct task_struct *new) {}
+
+#endif /* !CONFIG_CGROUPS */
+
+#endif /* _LINUX_CGROUP_H */