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authorLi Zefan <lizefan@huawei.com>2013-06-09 17:16:46 +0800
committerTejun Heo <tj@kernel.org>2013-06-13 10:48:33 -0700
commit88fa523bff295f1d60244a54833480b02f775152 (patch)
tree45231f9e9d1ec3612bbe3ce5d14673f27c4cbb12 /kernel/cpuset.c
parent5c5cc62321d9df7a9a608346fc649c4528380c8f (diff)
cpuset: allow to move tasks to empty cpusets
Currently some cpuset behaviors are not friendly when cpuset is co-mounted with other cgroup controllers. Now with this patchset if cpuset is mounted with sane_behavior option, it behaves differently: - Tasks will be kept in empty cpusets when hotplug happens and take masks of ancestors with non-empty cpus/mems, instead of being moved to an ancestor. - A task can be moved into an empty cpuset, and again it takes masks of ancestors, so the user can drop a task into a newly created cgroup without having to do anything for it. As tasks can reside in empy cpusets, here're some rules: - They can be moved to another cpuset, regardless it's empty or not. - Though it takes masks from ancestors, it takes other configs from the empty cpuset. - If the ancestors' masks are changed, those tasks will also be updated to take new masks. v2: add documentation in include/linux/cgroup.h Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cpuset.c')
-rw-r--r--kernel/cpuset.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3473dd2580d1..3b3fdfdd4d78 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -479,7 +479,7 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
*/
ret = -ENOSPC;
if ((cgroup_task_count(cur->css.cgroup) || cur->attach_in_progress) &&
- (cpumask_empty(trial->cpus_allowed) ||
+ (cpumask_empty(trial->cpus_allowed) &&
nodes_empty(trial->mems_allowed)))
goto out;
@@ -1466,8 +1466,13 @@ static int cpuset_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
mutex_lock(&cpuset_mutex);
+ /*
+ * We allow to move tasks into an empty cpuset if sane_behavior
+ * flag is set.
+ */
ret = -ENOSPC;
- if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
+ if (!cgroup_sane_behavior(cgrp) &&
+ (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
goto out_unlock;
cgroup_taskset_for_each(task, cgrp, tset) {