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authorTejun Heo <tj@kernel.org>2013-08-08 20:11:26 -0400
committerTejun Heo <tj@kernel.org>2013-08-08 20:11:26 -0400
commitc59cd3d840b1b0a8f996cbbd9132128dcaabbeb9 (patch)
treef2ad31b11b14c00cfaa5327a5a587fae56604866 /kernel/cgroup.c
parent0942eeeef68f9493c1bcb1a52baf612b73fcf9fb (diff)
downloadop-kernel-dev-c59cd3d840b1b0a8f996cbbd9132128dcaabbeb9.zip
op-kernel-dev-c59cd3d840b1b0a8f996cbbd9132128dcaabbeb9.tar.gz
cgroup: make cgroup_task_iter remember the cgroup being iterated
Currently all cgroup_task_iter functions require @cgrp to be passed in, which is superflous and increases chance of usage error. Make cgroup_task_iter remember the cgroup being iterated and drop @cgrp argument from next and end functions. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c32
1 files changed, 15 insertions, 17 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 15c93f9c..abc62ea 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3205,13 +3205,11 @@ EXPORT_SYMBOL_GPL(css_next_descendant_post);
/**
* cgroup_advance_task_iter - advance a task itererator to the next css_set
- * @cgrp: the cgroup to walk tasks of
* @it: the iterator to advance
*
* Advance @it to the next css_set to walk.
*/
-static void cgroup_advance_task_iter(struct cgroup *cgrp,
- struct cgroup_task_iter *it)
+static void cgroup_advance_task_iter(struct cgroup_task_iter *it)
{
struct list_head *l = it->cset_link;
struct cgrp_cset_link *link;
@@ -3220,7 +3218,7 @@ static void cgroup_advance_task_iter(struct cgroup *cgrp,
/* Advance to the next non-empty css_set */
do {
l = l->next;
- if (l == &cgrp->cset_links) {
+ if (l == &it->origin_cgrp->cset_links) {
it->cset_link = NULL;
return;
}
@@ -3257,21 +3255,22 @@ void cgroup_task_iter_start(struct cgroup *cgrp, struct cgroup_task_iter *it)
cgroup_enable_task_cg_lists();
read_lock(&css_set_lock);
+
+ it->origin_cgrp = cgrp;
it->cset_link = &cgrp->cset_links;
- cgroup_advance_task_iter(cgrp, it);
+
+ cgroup_advance_task_iter(it);
}
/**
* cgroup_task_iter_next - return the next task for the iterator
- * @cgrp: the cgroup to walk tasks of
* @it: the task iterator being iterated
*
* The "next" function for task iteration. @it should have been
* initialized via cgroup_task_iter_start(). Returns NULL when the
* iteration reaches the end.
*/
-struct task_struct *cgroup_task_iter_next(struct cgroup *cgrp,
- struct cgroup_task_iter *it)
+struct task_struct *cgroup_task_iter_next(struct cgroup_task_iter *it)
{
struct task_struct *res;
struct list_head *l = it->task;
@@ -3289,7 +3288,7 @@ struct task_struct *cgroup_task_iter_next(struct cgroup *cgrp,
* We reached the end of this task list - move on to the
* next cgrp_cset_link.
*/
- cgroup_advance_task_iter(cgrp, it);
+ cgroup_advance_task_iter(it);
} else {
it->task = l;
}
@@ -3298,12 +3297,11 @@ struct task_struct *cgroup_task_iter_next(struct cgroup *cgrp,
/**
* cgroup_task_iter_end - finish task iteration
- * @cgrp: the cgroup to walk tasks of
* @it: the task iterator to finish
*
* Finish task iteration started by cgroup_task_iter_start().
*/
-void cgroup_task_iter_end(struct cgroup *cgrp, struct cgroup_task_iter *it)
+void cgroup_task_iter_end(struct cgroup_task_iter *it)
__releases(css_set_lock)
{
read_unlock(&css_set_lock);
@@ -3409,7 +3407,7 @@ int cgroup_scan_tasks(struct cgroup_scanner *scan)
*/
heap->size = 0;
cgroup_task_iter_start(scan->cgrp, &it);
- while ((p = cgroup_task_iter_next(scan->cgrp, &it))) {
+ while ((p = cgroup_task_iter_next(&it))) {
/*
* Only affect tasks that qualify per the caller's callback,
* if he provided one
@@ -3442,7 +3440,7 @@ int cgroup_scan_tasks(struct cgroup_scanner *scan)
* the heap and wasn't inserted
*/
}
- cgroup_task_iter_end(scan->cgrp, &it);
+ cgroup_task_iter_end(&it);
if (heap->size) {
for (i = 0; i < heap->size; i++) {
@@ -3664,7 +3662,7 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
return -ENOMEM;
/* now, populate the array */
cgroup_task_iter_start(cgrp, &it);
- while ((tsk = cgroup_task_iter_next(cgrp, &it))) {
+ while ((tsk = cgroup_task_iter_next(&it))) {
if (unlikely(n == length))
break;
/* get tgid or pid for procs or tasks file respectively */
@@ -3675,7 +3673,7 @@ static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type,
if (pid > 0) /* make sure to only use valid results */
array[n++] = pid;
}
- cgroup_task_iter_end(cgrp, &it);
+ cgroup_task_iter_end(&it);
length = n;
/* now sort & (if procs) strip out duplicates */
sort(array, length, sizeof(pid_t), cmppid, NULL);
@@ -3724,7 +3722,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
cgrp = dentry->d_fsdata;
cgroup_task_iter_start(cgrp, &it);
- while ((tsk = cgroup_task_iter_next(cgrp, &it))) {
+ while ((tsk = cgroup_task_iter_next(&it))) {
switch (tsk->state) {
case TASK_RUNNING:
stats->nr_running++;
@@ -3744,7 +3742,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
break;
}
}
- cgroup_task_iter_end(cgrp, &it);
+ cgroup_task_iter_end(&it);
err:
return ret;
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