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

[Kamezawa Hiroyuki]

(2014/12/15 11:06), Lai Jiangshan wrote:
> 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@xxxxxxxxxxxxxx>
> > ---
> >   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().

Ah, hm. CPU_OFFLINE event does this, ok.

Thanks,
-Kame


> > +
> >   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


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