Re: [PATCH v3 2/3] mm,memory_hotplug: Implement numa node notifier

[Dan Carpenter <dan.carpenter@linaro.org>]

On Fri, May 02, 2025 at 11:28:02AM -0400, Gregory Price wrote:
> On Fri, May 02, 2025 at 10:36:23AM +0200, Oscar Salvador wrote:
> > There are at least six consumers of hotplug_memory_notifier that what they
> > really are interested in is whether any numa node changed its state, e.g: going
> > from being memory aware to becoming memoryless and vice versa.
> > 
> > Implement a specific notifier for numa nodes when their state gets changed,
> > and have those consumers that only care about numa node state changes use it.
> > 
> > Signed-off-by: Oscar Salvador <osalvador@suse.de>
> > Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >  
> > diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> > index f43951668c41..b3ad63fb3a2b 100644
> > --- a/mm/mempolicy.c
> > +++ b/mm/mempolicy.c
> > @@ -3591,20 +3591,20 @@ static int wi_node_notifier(struct notifier_block *nb,
> >  			       unsigned long action, void *data)
> >  {
> >  	int err;
> > -	struct memory_notify *arg = data;
> > +	struct node_notify *arg = data;
> >  	int nid = arg->status_change_nid;
> >  
> >  	if (nid < 0)
> >  		return NOTIFY_OK;
> >  
> >  	switch (action) {
> > -	case MEM_ONLINE:
> > +	case NODE_BECAME_MEM_AWARE:
> >  		err = sysfs_wi_node_add(nid);
> >  		if (err)
> >  			pr_err("failed to add sysfs for node%d during hotplug: %d\n",
> >  			       nid, err);
> >  		break;
> 
> May I suggest rolling this patch in with this change:
> https://lore.kernel.org/linux-mm/aAij2oUCP1zmcoPv@stanley.mountain/
> 
> seems to fix the underlying problem, and returning an error now makes
> sense given the change. 
> 
> +cc: Honggyu Kim, Dan Carpenter
> 

Oops.  I sent a v2 of that patch.  I imagine that Andrew will fold that
patch into Rakie Kim's patch.

https://lore.kernel.org/all/aBjL7Bwc0QBzgajK@stanley.mountain

regards,
dan carpenter