Re: [PATCH 3/4] workqueue: remove per-node unbound pool when node goes offline.

[Lai Jiangshan <laijs@cn.fujitsu.com>]

On 12/14/2014 12:35 AM, Kamezawa Hiroyuki wrote:
> remove node aware unbound pools if node goes offline.
> 
> scan unbound workqueue and remove numa affine pool when
> a node goes offline.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> ---
>  kernel/workqueue.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 35f4f00..07b4eb5 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -4921,11 +4921,40 @@ early_initcall(init_workqueues);
>   * cached pools per cpu should be freed at node unplug
>   */
>  
> +/*
> + * Replace per-node pwq with dfl_pwq because this node disappers.
> + * The new pool will be set at CPU_ONLINE by wq_update_unbound_numa.
> + */
> +static void wq_release_unbound_numa(struct workqueue_struct *wq, int nid)
> +{
> +	struct pool_workqueue *old_pwq = NULL;
> +
> +	if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND))
> +		return;
> +	mutex_lock(&wq->mutex);
> +	if (wq->unbound_attrs->no_numa)
> +		goto out_unlock;
> +	spin_lock_irq(&wq->dfl_pwq->pool->lock);
> +	get_pwq(wq->dfl_pwq);
> +	spin_unlock_irq(&wq->dfl_pwq->pool->lock);
> +	old_pwq = numa_pwq_tbl_install(wq, nid, wq->dfl_pwq);
> +out_unlock:
> +	mutex_unlock(&wq->mutex);
> +	put_pwq_unlocked(old_pwq);
> +	return;
> +}


We have already did it in wq_update_unbound_numa().

> +
>  void workqueue_register_numanode(int nid)
>  {
>  }
>   
>  void workqueue_unregister_numanode(int nid)
>  {
> +	struct workqueue_struct *wq;
> +
> +	mutex_lock(&wq_pool_mutex);
> +	list_for_each_entry(wq, &workqueues, list)
> +		wq_release_unbound_numa(wq, nid);
> +	mutex_unlock(&wq_pool_mutex);
>  }
>  #endif