Re: [PATCH] mm/slub: disallow obj's allocation on page with mismatched pfmemalloc purpose

[Pingfan Liu <kernelfans@gmail.com>]

On Thu, Sep 27, 2018 at 12:14 AM Christopher Lameter <cl@linux.com> wrote:
>
> On Wed, 26 Sep 2018, Pingfan Liu wrote:
>
> > -
> >       if (unlikely(!freelist)) {
> >               slab_out_of_memory(s, gfpflags, node);
> >               return NULL;
> >       }
> >
> > +     VM_BUG_ON(!pfmemalloc_match(page, gfpflags));
> >       page = c->page;
> > -     if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
> > +     if (likely(!kmem_cache_debug(s))
> >               goto load_freelist;
> >
> >       /* Only entered in the debug case */
> > -     if (kmem_cache_debug(s) &&
> > -                     !alloc_debug_processing(s, page, freelist, addr))
> > +     if (!alloc_debug_processing(s, page, freelist, addr))
> >               goto new_slab;  /* Slab failed checks. Next slab needed */
> > -
> > -     deactivate_slab(s, page, get_freepointer(s, freelist), c);
>
> In the debug case the slab needs to be deactivated. Otherwise the
> slowpath will not be used and debug checks on the following objects will
> not be done.
>
Got it.

Thanks,
Pingfan