diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 153 |
1 files changed, 85 insertions, 68 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 4766bb65e4d9..d8abe996e009 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -113,9 +113,9 @@ static int root_count; #define dummytop (&rootnode.top_cgroup) /* This flag indicates whether tasks in the fork and exit paths should - * take callback_mutex and check for fork/exit handlers to call. This - * avoids us having to do extra work in the fork/exit path if none of the - * subsystems need to be called. + * check for fork/exit handlers to call. This avoids us having to do + * extra work in the fork/exit path if none of the subsystems need to + * be called. */ static int need_forkexit_callback; @@ -307,7 +307,6 @@ static inline void put_css_set_taskexit(struct css_set *cg) * template: location in which to build the desired set of subsystem * state objects for the new cgroup group */ - static struct css_set *find_existing_css_set( struct css_set *oldcg, struct cgroup *cgrp, @@ -320,7 +319,7 @@ static struct css_set *find_existing_css_set( /* Built the set of subsystem state objects that we want to * see in the new css_set */ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { - if (root->subsys_bits & (1ull << i)) { + if (root->subsys_bits & (1UL << i)) { /* Subsystem is in this hierarchy. So we want * the subsystem state from the new * cgroup */ @@ -354,7 +353,6 @@ static struct css_set *find_existing_css_set( * and chains them on tmp through their cgrp_link_list fields. Returns 0 on * success or a negative error */ - static int allocate_cg_links(int count, struct list_head *tmp) { struct cg_cgroup_link *link; @@ -396,7 +394,6 @@ static void free_cg_links(struct list_head *tmp) * substituted into the appropriate hierarchy. Must be called with * cgroup_mutex held */ - static struct css_set *find_css_set( struct css_set *oldcg, struct cgroup *cgrp) { @@ -473,7 +470,6 @@ static struct css_set *find_css_set( /* Link this cgroup group into the list */ list_add(&res->list, &init_css_set.list); css_set_count++; - INIT_LIST_HEAD(&res->tasks); write_unlock(&css_set_lock); return res; @@ -507,8 +503,8 @@ static struct css_set *find_css_set( * critical pieces of code here. The exception occurs on cgroup_exit(), * when a task in a notify_on_release cgroup exits. Then cgroup_mutex * is taken, and if the cgroup count is zero, a usermode call made - * to /sbin/cgroup_release_agent with the name of the cgroup (path - * relative to the root of cgroup file system) as the argument. + * to the release agent with the name of the cgroup (path relative to + * the root of cgroup file system) as the argument. * * A cgroup can only be deleted if both its 'count' of using tasks * is zero, and its list of 'children' cgroups is empty. Since all @@ -521,7 +517,7 @@ static struct css_set *find_css_set( * * The need for this exception arises from the action of * cgroup_attach_task(), which overwrites one tasks cgroup pointer with - * another. It does so using cgroup_mutexe, however there are + * another. It does so using cgroup_mutex, however there are * several performance critical places that need to reference * task->cgroup without the expense of grabbing a system global * mutex. Therefore except as noted below, when dereferencing or, as @@ -537,7 +533,6 @@ static struct css_set *find_css_set( * cgroup_lock - lock out any changes to cgroup structures * */ - void cgroup_lock(void) { mutex_lock(&cgroup_mutex); @@ -548,7 +543,6 @@ void cgroup_lock(void) * * Undo the lock taken in a previous cgroup_lock() call. */ - void cgroup_unlock(void) { mutex_unlock(&cgroup_mutex); @@ -590,7 +584,6 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) * Call subsys's pre_destroy handler. * This is called before css refcnt check. */ - static void cgroup_call_pre_destroy(struct cgroup *cgrp) { struct cgroup_subsys *ss; @@ -600,7 +593,6 @@ static void cgroup_call_pre_destroy(struct cgroup *cgrp) return; } - static void cgroup_diput(struct dentry *dentry, struct inode *inode) { /* is dentry a directory ? if so, kfree() associated cgroup */ @@ -696,7 +688,7 @@ static int rebind_subsystems(struct cgroupfs_root *root, added_bits = final_bits & ~root->actual_subsys_bits; /* Check that any added subsystems are currently free */ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { - unsigned long long bit = 1ull << i; + unsigned long bit = 1UL << i; struct cgroup_subsys *ss = subsys[i]; if (!(bit & added_bits)) continue; @@ -927,7 +919,6 @@ static int cgroup_get_rootdir(struct super_block *sb) if (!inode) return -ENOMEM; - inode->i_op = &simple_dir_inode_operations; inode->i_fop = &simple_dir_operations; inode->i_op = &cgroup_dir_inode_operations; /* directories start off with i_nlink == 2 (for "." entry) */ @@ -961,8 +952,11 @@ static int cgroup_get_sb(struct file_system_type *fs_type, } root = kzalloc(sizeof(*root), GFP_KERNEL); - if (!root) + if (!root) { + if (opts.release_agent) + kfree(opts.release_agent); return -ENOMEM; + } init_cgroup_root(root); root->subsys_bits = opts.subsys_bits; @@ -1129,8 +1123,13 @@ static inline struct cftype *__d_cft(struct dentry *dentry) return dentry->d_fsdata; } -/* - * Called with cgroup_mutex held. Writes path of cgroup into buf. +/** + * cgroup_path - generate the path of a cgroup + * @cgrp: the cgroup in question + * @buf: the buffer to write the path into + * @buflen: the length of the buffer + * + * Called with cgroup_mutex held. Writes path of cgroup into buf. * Returns 0 on success, -errno on error. */ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) @@ -1188,11 +1187,13 @@ static void get_first_subsys(const struct cgroup *cgrp, *subsys_id = test_ss->subsys_id; } -/* - * Attach task 'tsk' to cgroup 'cgrp' +/** + * cgroup_attach_task - attach task 'tsk' to cgroup 'cgrp' + * @cgrp: the cgroup the task is attaching to + * @tsk: the task to be attached * - * Call holding cgroup_mutex. May take task_lock of - * the task 'pid' during call. + * Call holding cgroup_mutex. May take task_lock of + * the task 'tsk' during call. */ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) { @@ -1293,7 +1294,6 @@ static int attach_task_by_pid(struct cgroup *cgrp, char *pidbuf) } /* The various types of files and directories in a cgroup file system */ - enum cgroup_filetype { FILE_ROOT, FILE_DIR, @@ -1584,12 +1584,11 @@ static int cgroup_create_file(struct dentry *dentry, int mode, } /* - * cgroup_create_dir - create a directory for an object. - * cgrp: the cgroup we create the directory for. - * It must have a valid ->parent field - * And we are going to fill its ->dentry field. - * dentry: dentry of the new cgroup - * mode: mode to set on new directory. + * cgroup_create_dir - create a directory for an object. + * @cgrp: the cgroup we create the directory for. It must have a valid + * ->parent field. And we are going to fill its ->dentry field. + * @dentry: dentry of the new cgroup + * @mode: mode to set on new directory. */ static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry, int mode) @@ -1651,8 +1650,12 @@ int cgroup_add_files(struct cgroup *cgrp, return 0; } -/* Count the number of tasks in a cgroup. */ - +/** + * cgroup_task_count - count the number of tasks in a cgroup. + * @cgrp: the cgroup in question + * + * Return the number of tasks in the cgroup. + */ int cgroup_task_count(const struct cgroup *cgrp) { int count = 0; @@ -1962,12 +1965,13 @@ static int pid_array_load(pid_t *pidarray, int npids, struct cgroup *cgrp) } /** - * Build and fill cgroupstats so that taskstats can export it to user - * space. - * + * cgroupstats_build - build and fill cgroupstats * @stats: cgroupstats to fill information into * @dentry: A dentry entry belonging to the cgroup for which stats have * been requested. + * + * Build and fill cgroupstats so that taskstats can export it to user + * space. */ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) { @@ -2199,14 +2203,13 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, } /* - * cgroup_create - create a cgroup - * parent: cgroup that will be parent of the new cgroup. - * name: name of the new cgroup. Will be strcpy'ed. - * mode: mode to set on new inode + * cgroup_create - create a cgroup + * @parent: cgroup that will be parent of the new cgroup + * @dentry: dentry of the new cgroup + * @mode: mode to set on new inode * - * Must be called with the mutex on the parent inode held + * Must be called with the mutex on the parent inode held */ - static long cgroup_create(struct cgroup *parent, struct dentry *dentry, int mode) { @@ -2349,13 +2352,12 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) parent = cgrp->parent; root = cgrp->root; sb = root->sb; + /* - * Call pre_destroy handlers of subsys + * Call pre_destroy handlers of subsys. Notify subsystems + * that rmdir() request comes. */ cgroup_call_pre_destroy(cgrp); - /* - * Notify subsyses that rmdir() request comes. - */ if (cgroup_has_css_refs(cgrp)) { mutex_unlock(&cgroup_mutex); @@ -2431,8 +2433,10 @@ static void cgroup_init_subsys(struct cgroup_subsys *ss) } /** - * cgroup_init_early - initialize cgroups at system boot, and - * initialize any subsystems that request early init. + * cgroup_init_early - cgroup initialization at system boot + * + * Initialize cgroups at system boot, and initialize any + * subsystems that request early init. */ int __init cgroup_init_early(void) { @@ -2474,8 +2478,10 @@ int __init cgroup_init_early(void) } /** - * cgroup_init - register cgroup filesystem and /proc file, and - * initialize any subsystems that didn't request early init. + * cgroup_init - cgroup initialization + * + * Register cgroup filesystem and /proc file, and initialize + * any subsystems that didn't request early init. */ int __init cgroup_init(void) { @@ -2618,7 +2624,7 @@ static struct file_operations proc_cgroupstats_operations = { /** * cgroup_fork - attach newly forked task to its parents cgroup. - * @tsk: pointer to task_struct of forking parent process. + * @child: pointer to task_struct of forking parent process. * * Description: A task inherits its parent's cgroup at fork(). * @@ -2642,9 +2648,12 @@ void cgroup_fork(struct task_struct *child) } /** - * cgroup_fork_callbacks - called on a new task very soon before - * adding it to the tasklist. No need to take any locks since no-one - * can be operating on this task + * cgroup_fork_callbacks - run fork callbacks + * @child: the new task + * + * Called on a new task very soon before adding it to the + * tasklist. No need to take any locks since no-one can + * be operating on this task. */ void cgroup_fork_callbacks(struct task_struct *child) { @@ -2659,11 +2668,14 @@ void cgroup_fork_callbacks(struct task_struct *child) } /** - * cgroup_post_fork - called on a new task after adding it to the - * task list. Adds the task to the list running through its css_set - * if necessary. Has to be after the task is visible on the task list - * in case we race with the first call to cgroup_iter_start() - to - * guarantee that the new task ends up on its list. */ + * cgroup_post_fork - called on a new task after adding it to the task list + * @child: the task in question + * + * Adds the task to the list running through its css_set if necessary. + * Has to be after the task is visible on the task list in case we race + * with the first call to cgroup_iter_start() - to guarantee that the + * new task ends up on its list. + */ void cgroup_post_fork(struct task_struct *child) { if (use_task_css_set_links) { @@ -2676,6 +2688,7 @@ void cgroup_post_fork(struct task_struct *child) /** * cgroup_exit - detach cgroup from exiting task * @tsk: pointer to task_struct of exiting process + * @run_callback: run exit callbacks? * * Description: Detach cgroup from @tsk and release it. * @@ -2706,7 +2719,6 @@ void cgroup_post_fork(struct task_struct *child) * top_cgroup isn't going away, and either task has PF_EXITING set, * which wards off any cgroup_attach_task() attempts, or task is a failed * fork, never visible to cgroup_attach_task. - * */ void cgroup_exit(struct task_struct *tsk, int run_callbacks) { @@ -2743,9 +2755,13 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks) } /** - * cgroup_clone - duplicate the current cgroup in the hierarchy - * that the given subsystem is attached to, and move this task into - * the new child + * cgroup_clone - clone the cgroup the given subsystem is attached to + * @tsk: the task to be moved + * @subsys: the given subsystem + * + * Duplicate the current cgroup in the hierarchy that the given + * subsystem is attached to, and move this task into the new + * child. */ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys) { @@ -2858,9 +2874,12 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys) return ret; } -/* - * See if "cgrp" is a descendant of the current task's cgroup in - * the appropriate hierarchy +/** + * cgroup_is_descendant - see if @cgrp is a descendant of current task's cgrp + * @cgrp: the cgroup in question + * + * See if @cgrp is a descendant of the current task's cgroup in + * the appropriate hierarchy. * * If we are sending in dummytop, then presumably we are creating * the top cgroup in the subsystem. @@ -2939,9 +2958,7 @@ void __css_put(struct cgroup_subsys_state *css) * release agent task. We don't bother to wait because the caller of * this routine has no use for the exit status of the release agent * task, so no sense holding our caller up for that. - * */ - static void cgroup_release_agent(struct work_struct *work) { BUG_ON(work != &release_agent_work); |