diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 29 | ||||
| -rw-r--r-- | kernel/cpuset.c | 19 |
2 files changed, 40 insertions, 8 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 5e8dab5bf9adb..d6b729beba493 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3446,9 +3446,28 @@ 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) && !list_empty(&cgrp->cset_links)) { - ret = -EBUSY; - goto out_unlock; + 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; } /* save and update control masks and prepare csses */ @@ -3899,7 +3918,9 @@ void cgroup_file_notify(struct cgroup_file *cfile) * cgroup_task_count - count the number of tasks in a cgroup. * @cgrp: the cgroup in question * - * Return the number of tasks in the cgroup. + * 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) { diff --git a/kernel/cpuset.c b/kernel/cpuset.c index c27e53326befe..2b4c20ab5bbe1 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -325,8 +325,7 @@ static struct file_system_type cpuset_fs_type = { /* * Return in pmask the portion of a cpusets's cpus_allowed that * are online. If none are online, walk up the cpuset hierarchy - * until we find one that does have some online cpus. The top - * cpuset always has some cpus online. + * until we find one that does have some online cpus. * * One way or another, we guarantee to return some non-empty subset * of cpu_online_mask. @@ -335,8 +334,20 @@ static struct file_system_type cpuset_fs_type = { */ static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask) { - while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) + while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) { cs = parent_cs(cs); + if (unlikely(!cs)) { + /* + * The top cpuset doesn't have any online cpu as a + * consequence of a race between cpuset_hotplug_work + * and cpu hotplug notifier. But we know the top + * cpuset's effective_cpus is on its way to to be + * identical to cpu_online_mask. + */ + cpumask_copy(pmask, cpu_online_mask); + return; + } + } cpumask_and(pmask, cs->effective_cpus, cpu_online_mask); } @@ -2074,7 +2085,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) * which could have been changed by cpuset just after it inherits the * state from the parent and before it sits on the cgroup's task list. */ -void cpuset_fork(struct task_struct *task) +static void cpuset_fork(struct task_struct *task) { if (task_css_is_root(task, cpuset_cgrp_id)) return; |