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cgroup: consolidate cgroup_attach_task() and cgroup_attach_proc()

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These two functions share most of the code.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2013-03-13 09:17:09 +08:00 committed by Tejun Heo
parent bd2953ebbb
commit 081aa458c3
3 changed files with 23 additions and 91 deletions
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3
include/linux/cgroup.h
View File

@ -693,7 +693,8 @@ 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 *);
int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
bool threadgroup);
int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
/*

109
kernel/cgroup.c
View File

@ -59,7 +59,7 @@
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/eventfd.h>
#include <linux/poll.h>
#include <linux/flex_array.h> /* used in cgroup_attach_proc */
#include <linux/flex_array.h> /* used in cgroup_attach_task */
#include <linux/kthread.h>
#include <linux/atomic.h>
@ -1943,82 +1943,6 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp,
put_css_set(oldcg);
}
/**
* cgroup_attach_task - attach task 'tsk' to cgroup 'cgrp'
* @cgrp: the cgroup the task is attaching to
* @tsk: the task to be attached
*
* Call with cgroup_mutex and threadgroup locked. May take task_lock of
* @tsk during call.
*/
int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
{
int retval = 0;
struct cgroup_subsys *ss, *failed_ss = NULL;
struct cgroup *oldcgrp;
struct cgroupfs_root *root = cgrp->root;
struct cgroup_taskset tset = { };
struct css_set *newcg;
/* @tsk either already exited or can't exit until the end */
if (tsk->flags & PF_EXITING)
return -ESRCH;
/* Nothing to do if the task is already in that cgroup */
oldcgrp = task_cgroup_from_root(tsk, root);
if (cgrp == oldcgrp)
return 0;
tset.single.task = tsk;
tset.single.cgrp = oldcgrp;
for_each_subsys(root, ss) {
if (ss->can_attach) {
retval = ss->can_attach(cgrp, &tset);
if (retval) {
/*
* Remember on which subsystem the can_attach()
* failed, so that we only call cancel_attach()
* against the subsystems whose can_attach()
* succeeded. (See below)
*/
failed_ss = ss;
goto out;
}
}
}
newcg = find_css_set(tsk->cgroups, cgrp);
if (!newcg) {
retval = -ENOMEM;
goto out;
}
cgroup_task_migrate(cgrp, oldcgrp, tsk, newcg);
for_each_subsys(root, ss) {
if (ss->attach)
ss->attach(cgrp, &tset);
}
out:
if (retval) {
for_each_subsys(root, ss) {
if (ss == failed_ss)
/*
* This subsystem was the one that failed the
* can_attach() check earlier, so we don't need
* to call cancel_attach() against it or any
* remaining subsystems.
*/
break;
if (ss->cancel_attach)
ss->cancel_attach(cgrp, &tset);
}
}
return retval;
}
/**
* cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from'
* @from: attach to all cgroups of a given task
@ -2033,7 +1957,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
for_each_active_root(root) {
struct cgroup *from_cg = task_cgroup_from_root(from, root);
retval = cgroup_attach_task(from_cg, tsk);
retval = cgroup_attach_task(from_cg, tsk, false);
if (retval)
break;
}
@ -2044,21 +1968,22 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
/**
* cgroup_attach_proc - attach all threads in a threadgroup to a cgroup
* cgroup_attach_task - attach a task or a whole threadgroup to a cgroup
* @cgrp: the cgroup to attach to
* @leader: the threadgroup leader task_struct of the group to be attached
* @tsk: the task or the leader of the threadgroup to be attached
* @threadgroup: attach the whole threadgroup?
*
* Call holding cgroup_mutex and the group_rwsem of the leader. Will take
* task_lock of each thread in leader's threadgroup individually in turn.
* task_lock of @tsk or each thread in the threadgroup individually in turn.
*/
static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
bool threadgroup)
{
int retval, i, group_size;
struct cgroup_subsys *ss, *failed_ss = NULL;
/* guaranteed to be initialized later, but the compiler needs this */
struct cgroupfs_root *root = cgrp->root;
/* threadgroup list cursor and array */
struct task_struct *tsk;
struct task_struct *leader = tsk;
struct task_and_cgroup *tc;
struct flex_array *group;
struct cgroup_taskset tset = { };
@ -2070,7 +1995,10 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
* group - group_rwsem prevents new threads from appearing, and if
* threads exit, this will just be an over-estimate.
*/
group_size = get_nr_threads(leader);
if (threadgroup)
group_size = get_nr_threads(tsk);
else
group_size = 1;
/* flex_array supports very large thread-groups better than kmalloc. */
group = flex_array_alloc(sizeof(*tc), group_size, GFP_KERNEL);
if (!group)
@ -2080,7 +2008,6 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
if (retval)
goto out_free_group_list;
tsk = leader;
i = 0;
/*
* Prevent freeing of tasks while we take a snapshot. Tasks that are
@ -2109,6 +2036,9 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
retval = flex_array_put(group, i, &ent, GFP_ATOMIC);
BUG_ON(retval != 0);
i++;
if (!threadgroup)
break;
} while_each_thread(leader, tsk);
rcu_read_unlock();
/* remember the number of threads in the array for later. */
@ -2262,9 +2192,10 @@ retry_find_task:
put_task_struct(tsk);
goto retry_find_task;
}
ret = cgroup_attach_proc(cgrp, tsk);
} else
ret = cgroup_attach_task(cgrp, tsk);
}
ret = cgroup_attach_task(cgrp, tsk, threadgroup);
threadgroup_unlock(tsk);
put_task_struct(tsk);

2
kernel/cpuset.c
View File

@ -2008,7 +2008,7 @@ static void cpuset_do_move_task(struct task_struct *tsk,
struct cgroup *new_cgroup = scan->data;
cgroup_lock();
cgroup_attach_task(new_cgroup, tsk);
cgroup_attach_task(new_cgroup, tsk, false);
cgroup_unlock();
}