Re: [PATCH v4 2/2] mm: avoid slub allocation while holding list_lock

[Yu Zhao]

On Sat, Nov 09, 2019 at 11:16:28PM +0000, Christopher Lameter wrote:
> On Sat, 9 Nov 2019, Yu Zhao wrote:
> 
> > >  	struct page *page, *h;
> > > +	unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
> > > +
> > > +	if (!map)
> > > +		return;
> >
> > What would happen if we are trying to allocate from the slab that is
> > being shut down? And shouldn't the allocation be conditional (i.e.,
> > only when CONFIG_SLUB_DEBUG=y)?
> 
> Kmalloc slabs are never shut down.

Maybe I'm not thinking straight -- isn't it what caused the deadlock in
the first place?

Kmalloc slabs can be shut down when memcg is on.