On Wed 10-02-16 10:55:03, Tejun Heo wrote:
[...]
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -570,6 +570,16 @@ static struct pool_workqueue *unbound_pwq_by_node(struct
> workqueue_struct *wq,
> int node)
> {
> assert_rcu_or_wq_mutex_or_pool_mutex(wq);
> +
> + /*
> + * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a
> + * delayed item is pending. The plan is to keep CPU -> NODE
> + * mapping valid and stable across CPU on/offlines. Once that
> + * happens, this workaround can be removed.
I am not sure this is completely true with the code as is currently.
Don't wee also need to use cpu_to_mem to handle memoryless CPUs?
> + */
> + if (unlikely(node == NUMA_NO_NODE))
> + return wq->dfl_pwq;
> +
> return rcu_dereference_raw(wq->numa_pwq_tbl[node]);
> }
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c579dbab2e36..4785b895b9b5 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1325,7 +1325,7 @@ static void __queue_work(int cpu, struct workqueue_struct
*wq,
if (!(wq->flags & WQ_UNBOUND))
pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
else
- pwq = unbound_pwq_by_node(wq, cpu_to_node(cpu));
+ pwq = unbound_pwq_by_node(wq, cpu_to_mem(cpu));
/*
* If @work was previously on a different pool, it might still be
--
Michal Hocko
SUSE Labs
