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Diffstat (limited to 'kernel/cgroup/cpuset.c')
-rw-r--r--kernel/cgroup/cpuset.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 6a1942ed781c..b3b02b9c4405 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -729,7 +729,7 @@ static inline int nr_cpusets(void)
* load balancing domains (sched domains) as specified by that partial
* partition.
*
- * See "What is sched_load_balance" in Documentation/cgroup-v1/cpusets.txt
+ * See "What is sched_load_balance" in Documentation/cgroup-v1/cpusets.rst
* for a background explanation of this.
*
* Does not return errors, on the theory that the callers of this
@@ -2829,7 +2829,7 @@ static void cpuset_fork(struct task_struct *task)
if (task_css_is_root(task, cpuset_cgrp_id))
return;
- set_cpus_allowed_ptr(task, &current->cpus_allowed);
+ set_cpus_allowed_ptr(task, current->cpus_ptr);
task->mems_allowed = current->mems_allowed;
}
@@ -3254,10 +3254,23 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
spin_unlock_irqrestore(&callback_lock, flags);
}
+/**
+ * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe.
+ * @tsk: pointer to task_struct with which the scheduler is struggling
+ *
+ * Description: In the case that the scheduler cannot find an allowed cpu in
+ * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy
+ * mode however, this value is the same as task_cs(tsk)->effective_cpus,
+ * which will not contain a sane cpumask during cases such as cpu hotplugging.
+ * This is the absolute last resort for the scheduler and it is only used if
+ * _every_ other avenue has been traveled.
+ **/
+
void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
{
rcu_read_lock();
- do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
+ do_set_cpus_allowed(tsk, is_in_v2_mode() ?
+ task_cs(tsk)->cpus_allowed : cpu_possible_mask);
rcu_read_unlock();
/*