From: Lai Jiangshan <la...@linux.alibaba.com>
The commit d945b5e9f0e("workqueue: Fix setting affinity of unbound worker
threads") fixed a problem of set_cpus_allowed_ptr() with online&!active
cpumasks (more than one CPUs) when restore_unbound_workers_cpumask() in
online callback.
But now the new online callback for unbound workqueue is called later
than sched_cpu_activate(). So the cpu is set in cpu_active_mask and
set_cpus_allowed_ptr() with pool->attrs->cpumask in the code won't
cause such warning any more.
The said commit also left comments outdated and causes confusing.
It is better to change the code back.
Cc: Hillf Danton <hdan...@sina.com>
Reported-by: Hillf Danton <hdan...@sina.com>
Acked-by: Tejun Heo <t...@kernel.org>
Tested-by: Paul E. McKenney <paul...@kernel.org>
Signed-off-by: Lai Jiangshan <la...@linux.alibaba.com>
---
kernel/workqueue.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d7bdb7885e55..38628e2a622c 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5039,11 +5039,15 @@ static void restore_unbound_workers_cpumask(struct
worker_pool *pool, int cpu)
if (!cpumask_test_cpu(cpu, pool->attrs->cpumask))
return;
+ /* is @cpu the only online CPU? */
cpumask_and(&cpumask, pool->attrs->cpumask, cpu_online_mask);
+ if (cpumask_weight(&cpumask) != 1)
+ return;
/* as we're called from CPU_ONLINE, the following shouldn't fail */
for_each_pool_worker(worker, pool)
- WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0);
+ WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
+ pool->attrs->cpumask) < 0);
}
int workqueue_prepare_cpu(unsigned int cpu)
--
2.19.1.6.gb485710b
