Re: [PATCH 2/7] cgroup: fix comments

[Paul Menage]

On Wed, Feb 20, 2008 at 6:14 PM, Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:
> Paul Menage wrote:
>  > I think that docbook-style function comments need /** at the start of
>  > the comment block.
>  >
>
>  Yes, I didn't notice it. I revised the patch to fix it.
>
>
>  ---
>
>
>  fix:
>  - comments about need_forkexit_callback
>  - comments about release agent
>  - typo and comment style, etc.
>
>  Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx>

Acked-by: Paul Menage <menage@xxxxxxxxxx>

>  ---
>   include/linux/cgroup.h |    2 +-
>   kernel/cgroup.c        |  142 +++++++++++++++++++++++++++---------------------
>   2 files changed, 80 insertions(+), 64 deletions(-)
>
>
>  diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
>  index ff9055f..2ebf7af 100644
>  --- a/include/linux/cgroup.h
>  +++ b/include/linux/cgroup.h
>  @@ -175,7 +175,7 @@ struct css_set {
>   *
>   *
>   * When reading/writing to a file:
>  - *     - the cgroup to use in file->f_dentry->d_parent->d_fsdata
>  + *     - the cgroup to use is file->f_dentry->d_parent->d_fsdata
>   *     - the 'cftype' of the file is file->f_dentry->d_fsdata
>   */
>
>  diff --git a/kernel/cgroup.c b/kernel/cgroup.c
>  index 4766bb6..36066d8 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,
>  @@ -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)
>   {
>  @@ -507,8 +504,8 @@ 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 +518,7 @@ 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 +534,6 @@ 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 +544,6 @@ void cgroup_lock(void)
>   *
>   * Undo the lock taken in a previous cgroup_lock() call.
>   */
>  -
>   void cgroup_unlock(void)
>   {
>         mutex_unlock(&cgroup_mutex);
>  @@ -590,7 +585,6 @@ 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 +594,6 @@ 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 */
>  @@ -1129,8 +1122,13 @@ 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 +1186,13 @@ 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 +1293,6 @@ 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 +1583,11 @@ 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 +1649,12 @@ 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 +1964,13 @@ 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 +2202,13 @@ 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 +2351,12 @@ 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 +2432,10 @@ 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 +2477,10 @@ 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 +2623,7 @@ 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 +2647,12 @@ 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 +2667,14 @@ 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 +2687,7 @@ 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 +2718,6 @@ 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 +2754,13 @@ 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 +2873,12 @@ 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 +2957,7 @@ 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);
>  --
>  1.5.4.rc3
>
>
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