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Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r--kernel/sched/core.c21
1 files changed, 10 insertions, 11 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 56b09628692a..ff74fca39ed2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2342,7 +2342,9 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
if (p->flags & PF_KTHREAD || is_migration_disabled(p)) {
/*
- * Kernel threads are allowed on online && !active CPUs.
+ * Kernel threads are allowed on online && !active CPUs,
+ * however, during cpu-hot-unplug, even these might get pushed
+ * away if not KTHREAD_IS_PER_CPU.
*
* Specifically, migration_disabled() tasks must not fail the
* cpumask_any_and_distribute() pick below, esp. so on
@@ -2386,16 +2388,6 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
__do_set_cpus_allowed(p, new_mask, flags);
- if (p->flags & PF_KTHREAD) {
- /*
- * For kernel threads that do indeed end up on online &&
- * !active we want to ensure they are strict per-CPU threads.
- */
- WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) &&
- !cpumask_intersects(new_mask, cpu_active_mask) &&
- p->nr_cpus_allowed != 1);
- }
-
return affine_move_task(rq, p, &rf, dest_cpu, flags);
out:
@@ -7518,6 +7510,13 @@ int sched_cpu_deactivate(unsigned int cpu)
int ret;
set_cpu_active(cpu, false);
+
+ /*
+ * From this point forward, this CPU will refuse to run any task that
+ * is not: migrate_disable() or KTHREAD_IS_PER_CPU, and will actively
+ * push those tasks away until this gets cleared, see
+ * sched_cpu_dying().
+ */
balance_push_set(cpu, true);
/*