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

[Christopher Lameter]

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.

The allocation does not hurt and CONFIG_SLUB_DEBUG is on in most
configurations.