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-rw-r--r--kernel/cpuset.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 820870a715f8..4b409d2ecbb9 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -77,6 +77,26 @@ struct cpuset {
unsigned long flags; /* "unsigned long" so bitops work */
+ /*
+ * On default hierarchy:
+ *
+ * The user-configured masks can only be changed by writing to
+ * cpuset.cpus and cpuset.mems, and won't be limited by the
+ * parent masks.
+ *
+ * The effective masks is the real masks that apply to the tasks
+ * in the cpuset. They may be changed if the configured masks are
+ * changed or hotplug happens.
+ *
+ * effective_mask == configured_mask & parent's effective_mask,
+ * and if it ends up empty, it will inherit the parent's mask.
+ *
+ *
+ * On legacy hierachy:
+ *
+ * The user-configured masks are always the same with effective masks.
+ */
+
/* user-configured CPUs and Memory Nodes allow to tasks */
cpumask_var_t cpus_allowed;
nodemask_t mems_allowed;
@@ -450,9 +470,9 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
par = parent_cs(cur);
- /* We must be a subset of our parent cpuset */
+ /* On legacy hiearchy, we must be a subset of our parent cpuset. */
ret = -EACCES;
- if (!is_cpuset_subset(trial, par))
+ if (!cgroup_on_dfl(cur->css.cgroup) && !is_cpuset_subset(trial, par))
goto out;
/*
@@ -2167,6 +2187,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
static cpumask_t new_cpus;
static nodemask_t new_mems;
bool cpus_updated, mems_updated;
+ bool on_dfl = cgroup_on_dfl(top_cpuset.css.cgroup);
mutex_lock(&cpuset_mutex);
@@ -2174,13 +2195,14 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
cpumask_copy(&new_cpus, cpu_active_mask);
new_mems = node_states[N_MEMORY];
- cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus);
- mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems);
+ cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
+ mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
/* synchronize cpus_allowed to cpu_active_mask */
if (cpus_updated) {
mutex_lock(&callback_mutex);
- cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
+ if (!on_dfl)
+ cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
mutex_unlock(&callback_mutex);
/* we don't mess with cpumasks of tasks in top_cpuset */
@@ -2189,7 +2211,8 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
/* synchronize mems_allowed to N_MEMORY */
if (mems_updated) {
mutex_lock(&callback_mutex);
- top_cpuset.mems_allowed = new_mems;
+ if (!on_dfl)
+ top_cpuset.mems_allowed = new_mems;
top_cpuset.effective_mems = new_mems;
mutex_unlock(&callback_mutex);
update_tasks_nodemask(&top_cpuset);
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