Eric Lee / linux-smarc-t335x-v3.2

Download as
Browse Code ยป

Commit a043e3b2c63445512c5592cbe3c8694f3c655e81

Authored by Li Zefan
Committed by Linus Torvalds
1 parent d19e058330
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

cgroup: fix comments 

fix:
- comments about need_forkexit_callback
- comments about release agent
- typo and comment style, etc.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 2 changed files with 80 additions and 64 deletions Side-by-side Diff

include/linux/cgroup.h
Diff comments   View file @ a043e3b
... ... @@ -175,7 +175,7 @@
175 175 *
176 176 *
177 177 * When reading/writing to a file:
178   - * - the cgroup to use in file->f_dentry->d_parent->d_fsdata
  178 + * - the cgroup to use is file->f_dentry->d_parent->d_fsdata
179 179 * - the 'cftype' of the file is file->f_dentry->d_fsdata
180 180 */
181 181  
... ... @@ -113,9 +113,9 @@
113 113 #define dummytop (&rootnode.top_cgroup)
114 114  
115 115 /* This flag indicates whether tasks in the fork and exit paths should
116   - * take callback_mutex and check for fork/exit handlers to call. This
117   - * avoids us having to do extra work in the fork/exit path if none of the
118   - * subsystems need to be called.
  116 + * check for fork/exit handlers to call. This avoids us having to do
  117 + * extra work in the fork/exit path if none of the subsystems need to
  118 + * be called.
119 119 */
120 120 static int need_forkexit_callback;
121 121  
... ... @@ -307,7 +307,6 @@
307 307 * template: location in which to build the desired set of subsystem
308 308 * state objects for the new cgroup group
309 309 */
310   -
311 310 static struct css_set *find_existing_css_set(
312 311 struct css_set *oldcg,
313 312 struct cgroup *cgrp,
... ... @@ -354,7 +353,6 @@
354 353 * and chains them on tmp through their cgrp_link_list fields. Returns 0 on
355 354 * success or a negative error
356 355 */
357   -
358 356 static int allocate_cg_links(int count, struct list_head *tmp)
359 357 {
360 358 struct cg_cgroup_link *link;
... ... @@ -396,7 +394,6 @@
396 394 * substituted into the appropriate hierarchy. Must be called with
397 395 * cgroup_mutex held
398 396 */
399   -
400 397 static struct css_set *find_css_set(
401 398 struct css_set *oldcg, struct cgroup *cgrp)
402 399 {
... ... @@ -507,8 +504,8 @@
507 504 * critical pieces of code here. The exception occurs on cgroup_exit(),
508 505 * when a task in a notify_on_release cgroup exits. Then cgroup_mutex
509 506 * is taken, and if the cgroup count is zero, a usermode call made
510   - * to /sbin/cgroup_release_agent with the name of the cgroup (path
511   - * relative to the root of cgroup file system) as the argument.
  507 + * to the release agent with the name of the cgroup (path relative to
  508 + * the root of cgroup file system) as the argument.
512 509 *
513 510 * A cgroup can only be deleted if both its 'count' of using tasks
514 511 * is zero, and its list of 'children' cgroups is empty. Since all
... ... @@ -521,7 +518,7 @@
521 518 *
522 519 * The need for this exception arises from the action of
523 520 * cgroup_attach_task(), which overwrites one tasks cgroup pointer with
524   - * another. It does so using cgroup_mutexe, however there are
  521 + * another. It does so using cgroup_mutex, however there are
525 522 * several performance critical places that need to reference
526 523 * task->cgroup without the expense of grabbing a system global
527 524 * mutex. Therefore except as noted below, when dereferencing or, as
... ... @@ -537,7 +534,6 @@
537 534 * cgroup_lock - lock out any changes to cgroup structures
538 535 *
539 536 */
540   -
541 537 void cgroup_lock(void)
542 538 {
543 539 mutex_lock(&cgroup_mutex);
... ... @@ -548,7 +544,6 @@
548 544 *
549 545 * Undo the lock taken in a previous cgroup_lock() call.
550 546 */
551   -
552 547 void cgroup_unlock(void)
553 548 {
554 549 mutex_unlock(&cgroup_mutex);
... ... @@ -590,7 +585,6 @@
590 585 * Call subsys's pre_destroy handler.
591 586 * This is called before css refcnt check.
592 587 */
593   -
594 588 static void cgroup_call_pre_destroy(struct cgroup *cgrp)
595 589 {
596 590 struct cgroup_subsys *ss;
... ... @@ -600,7 +594,6 @@
600 594 return;
601 595 }
602 596  
603   -
604 597 static void cgroup_diput(struct dentry *dentry, struct inode *inode)
605 598 {
606 599 /* is dentry a directory ? if so, kfree() associated cgroup */
... ... @@ -1129,8 +1122,13 @@
1129 1122 return dentry->d_fsdata;
1130 1123 }
1131 1124  
1132   -/*
1133   - * Called with cgroup_mutex held. Writes path of cgroup into buf.
  1125 +/**
  1126 + * cgroup_path - generate the path of a cgroup
  1127 + * @cgrp: the cgroup in question
  1128 + * @buf: the buffer to write the path into
  1129 + * @buflen: the length of the buffer
  1130 + *
  1131 + * Called with cgroup_mutex held. Writes path of cgroup into buf.
1134 1132 * Returns 0 on success, -errno on error.
1135 1133 */
1136 1134 int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
1137 1135  
... ... @@ -1188,11 +1186,13 @@
1188 1186 *subsys_id = test_ss->subsys_id;
1189 1187 }
1190 1188  
1191   -/*
1192   - * Attach task 'tsk' to cgroup 'cgrp'
  1189 +/**
  1190 + * cgroup_attach_task - attach task 'tsk' to cgroup 'cgrp'
  1191 + * @cgrp: the cgroup the task is attaching to
  1192 + * @tsk: the task to be attached
1193 1193 *
1194   - * Call holding cgroup_mutex. May take task_lock of
1195   - * the task 'pid' during call.
  1194 + * Call holding cgroup_mutex. May take task_lock of
  1195 + * the task 'tsk' during call.
1196 1196 */
1197 1197 int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
1198 1198 {
... ... @@ -1293,7 +1293,6 @@
1293 1293 }
1294 1294  
1295 1295 /* The various types of files and directories in a cgroup file system */
1296   -
1297 1296 enum cgroup_filetype {
1298 1297 FILE_ROOT,
1299 1298 FILE_DIR,
... ... @@ -1584,12 +1583,11 @@
1584 1583 }
1585 1584  
1586 1585 /*
1587   - * cgroup_create_dir - create a directory for an object.
1588   - * cgrp: the cgroup we create the directory for.
1589   - * It must have a valid ->parent field
1590   - * And we are going to fill its ->dentry field.
1591   - * dentry: dentry of the new cgroup
1592   - * mode: mode to set on new directory.
  1586 + * cgroup_create_dir - create a directory for an object.
  1587 + * @cgrp: the cgroup we create the directory for. It must have a valid
  1588 + * ->parent field. And we are going to fill its ->dentry field.
  1589 + * @dentry: dentry of the new cgroup
  1590 + * @mode: mode to set on new directory.
1593 1591 */
1594 1592 static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry,
1595 1593 int mode)
... ... @@ -1651,8 +1649,12 @@
1651 1649 return 0;
1652 1650 }
1653 1651  
1654   -/* Count the number of tasks in a cgroup. */
1655   -
  1652 +/**
  1653 + * cgroup_task_count - count the number of tasks in a cgroup.
  1654 + * @cgrp: the cgroup in question
  1655 + *
  1656 + * Return the number of tasks in the cgroup.
  1657 + */
1656 1658 int cgroup_task_count(const struct cgroup *cgrp)
1657 1659 {
1658 1660 int count = 0;
1659 1661  
... ... @@ -1962,12 +1964,13 @@
1962 1964 }
1963 1965  
1964 1966 /**
1965   - * Build and fill cgroupstats so that taskstats can export it to user
1966   - * space.
1967   - *
  1967 + * cgroupstats_build - build and fill cgroupstats
1968 1968 * @stats: cgroupstats to fill information into
1969 1969 * @dentry: A dentry entry belonging to the cgroup for which stats have
1970 1970 * been requested.
  1971 + *
  1972 + * Build and fill cgroupstats so that taskstats can export it to user
  1973 + * space.
1971 1974 */
1972 1975 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
1973 1976 {
1974 1977  
1975 1978  
... ... @@ -2199,14 +2202,13 @@
2199 2202 }
2200 2203  
2201 2204 /*
2202   - * cgroup_create - create a cgroup
2203   - * parent: cgroup that will be parent of the new cgroup.
2204   - * name: name of the new cgroup. Will be strcpy'ed.
2205   - * mode: mode to set on new inode
  2205 + * cgroup_create - create a cgroup
  2206 + * @parent: cgroup that will be parent of the new cgroup
  2207 + * @dentry: dentry of the new cgroup
  2208 + * @mode: mode to set on new inode
2206 2209 *
2207   - * Must be called with the mutex on the parent inode held
  2210 + * Must be called with the mutex on the parent inode held
2208 2211 */
2209   -
2210 2212 static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
2211 2213 int mode)
2212 2214 {
2213 2215  
2214 2216  
... ... @@ -2349,13 +2351,12 @@
2349 2351 parent = cgrp->parent;
2350 2352 root = cgrp->root;
2351 2353 sb = root->sb;
  2354 +
2352 2355 /*
2353   - * Call pre_destroy handlers of subsys
  2356 + * Call pre_destroy handlers of subsys. Notify subsystems
  2357 + * that rmdir() request comes.
2354 2358 */
2355 2359 cgroup_call_pre_destroy(cgrp);
2356   - /*
2357   - * Notify subsyses that rmdir() request comes.
2358   - */
2359 2360  
2360 2361 if (cgroup_has_css_refs(cgrp)) {
2361 2362 mutex_unlock(&cgroup_mutex);
... ... @@ -2431,8 +2432,10 @@
2431 2432 }
2432 2433  
2433 2434 /**
2434   - * cgroup_init_early - initialize cgroups at system boot, and
2435   - * initialize any subsystems that request early init.
  2435 + * cgroup_init_early - cgroup initialization at system boot
  2436 + *
  2437 + * Initialize cgroups at system boot, and initialize any
  2438 + * subsystems that request early init.
2436 2439 */
2437 2440 int __init cgroup_init_early(void)
2438 2441 {
... ... @@ -2474,8 +2477,10 @@
2474 2477 }
2475 2478  
2476 2479 /**
2477   - * cgroup_init - register cgroup filesystem and /proc file, and
2478   - * initialize any subsystems that didn't request early init.
  2480 + * cgroup_init - cgroup initialization
  2481 + *
  2482 + * Register cgroup filesystem and /proc file, and initialize
  2483 + * any subsystems that didn't request early init.
2479 2484 */
2480 2485 int __init cgroup_init(void)
2481 2486 {
... ... @@ -2618,7 +2623,7 @@
2618 2623  
2619 2624 /**
2620 2625 * cgroup_fork - attach newly forked task to its parents cgroup.
2621   - * @tsk: pointer to task_struct of forking parent process.
  2626 + * @child: pointer to task_struct of forking parent process.
2622 2627 *
2623 2628 * Description: A task inherits its parent's cgroup at fork().
2624 2629 *
... ... @@ -2642,9 +2647,12 @@
2642 2647 }
2643 2648  
2644 2649 /**
2645   - * cgroup_fork_callbacks - called on a new task very soon before
2646   - * adding it to the tasklist. No need to take any locks since no-one
2647   - * can be operating on this task
  2650 + * cgroup_fork_callbacks - run fork callbacks
  2651 + * @child: the new task
  2652 + *
  2653 + * Called on a new task very soon before adding it to the
  2654 + * tasklist. No need to take any locks since no-one can
  2655 + * be operating on this task.
2648 2656 */
2649 2657 void cgroup_fork_callbacks(struct task_struct *child)
2650 2658 {
... ... @@ -2659,11 +2667,14 @@
2659 2667 }
2660 2668  
2661 2669 /**
2662   - * cgroup_post_fork - called on a new task after adding it to the
2663   - * task list. Adds the task to the list running through its css_set
2664   - * if necessary. Has to be after the task is visible on the task list
2665   - * in case we race with the first call to cgroup_iter_start() - to
2666   - * guarantee that the new task ends up on its list. */
  2670 + * cgroup_post_fork - called on a new task after adding it to the task list
  2671 + * @child: the task in question
  2672 + *
  2673 + * Adds the task to the list running through its css_set if necessary.
  2674 + * Has to be after the task is visible on the task list in case we race
  2675 + * with the first call to cgroup_iter_start() - to guarantee that the
  2676 + * new task ends up on its list.
  2677 + */
2667 2678 void cgroup_post_fork(struct task_struct *child)
2668 2679 {
2669 2680 if (use_task_css_set_links) {
... ... @@ -2676,6 +2687,7 @@
2676 2687 /**
2677 2688 * cgroup_exit - detach cgroup from exiting task
2678 2689 * @tsk: pointer to task_struct of exiting process
  2690 + * @run_callback: run exit callbacks?
2679 2691 *
2680 2692 * Description: Detach cgroup from @tsk and release it.
2681 2693 *
... ... @@ -2706,7 +2718,6 @@
2706 2718 * top_cgroup isn't going away, and either task has PF_EXITING set,
2707 2719 * which wards off any cgroup_attach_task() attempts, or task is a failed
2708 2720 * fork, never visible to cgroup_attach_task.
2709   - *
2710 2721 */
2711 2722 void cgroup_exit(struct task_struct *tsk, int run_callbacks)
2712 2723 {
... ... @@ -2743,9 +2754,13 @@
2743 2754 }
2744 2755  
2745 2756 /**
2746   - * cgroup_clone - duplicate the current cgroup in the hierarchy
2747   - * that the given subsystem is attached to, and move this task into
2748   - * the new child
  2757 + * cgroup_clone - clone the cgroup the given subsystem is attached to
  2758 + * @tsk: the task to be moved
  2759 + * @subsys: the given subsystem
  2760 + *
  2761 + * Duplicate the current cgroup in the hierarchy that the given
  2762 + * subsystem is attached to, and move this task into the new
  2763 + * child.
2749 2764 */
2750 2765 int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys)
2751 2766 {
2752 2767  
... ... @@ -2858,10 +2873,13 @@
2858 2873 return ret;
2859 2874 }
2860 2875  
2861   -/*
2862   - * See if "cgrp" is a descendant of the current task's cgroup in
2863   - * the appropriate hierarchy
  2876 +/**
  2877 + * cgroup_is_descendant - see if @cgrp is a descendant of current task's cgrp
  2878 + * @cgrp: the cgroup in question
2864 2879 *
  2880 + * See if @cgrp is a descendant of the current task's cgroup in
  2881 + * the appropriate hierarchy.
  2882 + *
2865 2883 * If we are sending in dummytop, then presumably we are creating
2866 2884 * the top cgroup in the subsystem.
2867 2885 *
2868 2886  
... ... @@ -2939,9 +2957,7 @@
2939 2957 * release agent task. We don't bother to wait because the caller of
2940 2958 * this routine has no use for the exit status of the release agent
2941 2959 * task, so no sense holding our caller up for that.
2942   - *
2943 2960 */
2944   -
2945 2961 static void cgroup_release_agent(struct work_struct *work)
2946 2962 {
2947 2963 BUG_ON(work != &release_agent_work);