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| author | Tejun Heo | 2014-02-13 12:58:39 +0100 |
|---|---|---|
| committer | Tejun Heo | 2014-02-13 12:58:39 +0100 |
| commit | 07bc356ed2950048d33d667e933e1b913c6e6b6d (patch) | |
| tree | 5efb91f14c21157285965cfcbf480a3538dda35e /mm/memcontrol.c | |
| parent | cgroup: relocate cgroup_enable_task_cg_lists() (diff) | |
| download | kernel-qcow2-linux-07bc356ed2950048d33d667e933e1b913c6e6b6d.tar.gz kernel-qcow2-linux-07bc356ed2950048d33d667e933e1b913c6e6b6d.tar.xz kernel-qcow2-linux-07bc356ed2950048d33d667e933e1b913c6e6b6d.zip | |
cgroup: implement cgroup_has_tasks() and unexport cgroup_task_count()
cgroup_task_count() read-locks css_set_lock and walks all tasks to
count them and then returns the result. The only thing all the users
want is determining whether the cgroup is empty or not. This patch
implements cgroup_has_tasks() which tests whether cgroup->cset_links
is empty, replaces all cgroup_task_count() usages and unexports it.
Note that the test isn't synchronized. This is the same as before.
The test has always been racy.
This will help planned css_set locking update.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c1c25494f7ae..d9c6ac1532e6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4958,7 +4958,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) struct cgroup *cgrp = memcg->css.cgroup; /* returns EBUSY if there is a task or if we come here twice. */ - if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) + if (cgroup_has_tasks(cgrp) || !list_empty(&cgrp->children)) return -EBUSY; /* we call try-to-free pages for make this cgroup empty */ @@ -5140,7 +5140,7 @@ static int __memcg_activate_kmem(struct mem_cgroup *memcg, * of course permitted. */ mutex_lock(&memcg_create_mutex); - if (cgroup_task_count(memcg->css.cgroup) || memcg_has_children(memcg)) + if (cgroup_has_tasks(memcg->css.cgroup) || memcg_has_children(memcg)) err = -EBUSY; mutex_unlock(&memcg_create_mutex); if (err) |