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| author |   Waiman Long <longman@redhat.com> | 2017-06-13 17:18:01 -0400 |
|---|---|---|
| committer |   Tejun Heo <tj@kernel.org> | 2017-06-14 16:01:21 -0400 |
| commit | 73a7242a06ff995d771fbe243e72b516feaa6e3d (patch) | |
| tree | bf8fd976dc8adf41d6291acd83b20ea10c4fa7e5 /kernel/cgroup/cgroup-v1.c | |
| parent | Merge tag 'xtensa-20170612' of git://github.com/jcmvbkbc/linux-xtensa (diff) | |
| download | linux-dev-73a7242a06ff995d771fbe243e72b516feaa6e3d.tar.xz linux-dev-73a7242a06ff995d771fbe243e72b516feaa6e3d.zip | |
cgroup: Keep accurate count of tasks in each css_set
The reference count in the css_set data structure was used as a
proxy of the number of tasks attached to that css_set. However, that
count is actually not an accurate measure especially with thread mode
support. So a new variable nr_tasks is added to the css_set to keep
track of the actual task count. This new variable is protected by
the css_set_lock. Functions that require the actual task count are
updated to use the new variable.
tj: s/task_count/nr_tasks/ for consistency with cgroup_root->nr_cgrps.
Refreshed on top of cgroup/for-v4.13 which dropped on
css_set_populated() -> nr_tasks conversion.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | kernel/cgroup/cgroup-v1.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index 85d75152402d..e9ea5f201fac 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -334,10 +334,6 @@ static struct cgroup_pidlist *cgroup_pidlist_find_create(struct cgroup *cgrp, /** * cgroup_task_count - count the number of tasks in a cgroup. * @cgrp: the cgroup in question - * - * Return the number of tasks in the cgroup. The returned number can be - * higher than the actual number of tasks due to css_set references from - * namespace roots and temporary usages. */ static int cgroup_task_count(const struct cgroup *cgrp) { @@ -346,7 +342,7 @@ static int cgroup_task_count(const struct cgroup *cgrp) spin_lock_irq(&css_set_lock); list_for_each_entry(link, &cgrp->cset_links, cset_link) - count += refcount_read(&link->cset->refcount); + count += link->cset->nr_tasks; spin_unlock_irq(&css_set_lock); return count; } |