workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs

When a CPU is going offline, all workers on the CPU's pool will have their
cpus_allowed cleared to cpu_possible_mask and can run on any CPUs including
the isolated ones. Instead, set cpus_allowed to wq_unbound_cpumask so that
the can avoid isolated CPUs.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0d2514b4ff0d2baf5020d0bd71fec91ed1f283fa..4056f2a3f9d59c0dbaa776e5bb8bce31390a1600 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5001,7 +5001,7 @@ static void unbind_workers(int cpu)
 
                for_each_pool_worker(worker, pool) {
                        kthread_set_per_cpu(worker->task, -1);
-                       WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0);
+                       WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0);
                }
 
                mutex_unlock(&wq_pool_attach_mutex);