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| author | Tejun Heo <tj@kernel.org> | 2017-07-17 04:44:18 +0300 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-07-17 04:44:45 +0300 |
| commit | 27f26753f8c063c4cd2f06318e977ae136574b28 (patch) | |
| tree | f681a235e238768102fe5465c559d984d58b39fc /kernel/cgroup | |
| parent | 788b950c62e06b02278a0fd380e1a0667996ce3c (diff) | |
| download | linux-27f26753f8c063c4cd2f06318e977ae136574b28.tar.xz | |
cgroup: replace css_set walking populated test with testing cgrp->nr_populated_csets
Implement trivial cgroup_has_tasks() which tests whether
cgrp->nr_populated_csets is zero and replace the explicit local
populated test in cgroup_subtree_control(). This simplifies the code
and cgroup_has_tasks() will be used in more places later.
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 30 |
1 files changed, 8 insertions, 22 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 5fe2644cd0f3..d5b62313c753 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -325,6 +325,11 @@ static struct cgroup *cgroup_parent(struct cgroup *cgrp) return NULL; } +static bool cgroup_has_tasks(struct cgroup *cgrp) +{ + return cgrp->nr_populated_csets; +} + /* subsystems visibly enabled on a cgroup */ static u16 cgroup_control(struct cgroup *cgrp) { @@ -2971,28 +2976,9 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, * Except for the root, subtree_control must be zero for a cgroup * with tasks so that child cgroups don't compete against tasks. */ - if (enable && cgroup_parent(cgrp)) { - struct cgrp_cset_link *link; - - /* - * Because namespaces pin csets too, @cgrp->cset_links - * might not be empty even when @cgrp is empty. Walk and - * verify each cset. - */ - spin_lock_irq(&css_set_lock); - - ret = 0; - list_for_each_entry(link, &cgrp->cset_links, cset_link) { - if (css_set_populated(link->cset)) { - ret = -EBUSY; - break; - } - } - - spin_unlock_irq(&css_set_lock); - - if (ret) - goto out_unlock; + if (enable && cgroup_parent(cgrp) && cgroup_has_tasks(cgrp)) { + ret = -EBUSY; + goto out_unlock; } /* save and update control masks and prepare csses */ |