Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

Nicolas Boichat
2018-12-06T10:10:57Z

On Thu, Dec 6, 2018 at 5:37 PM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> On 12/6/18 4:49 AM, Nicolas Boichat wrote:
> >> So it would be fine even unchanged. The check would anyway need some
> >> more love to catch the same with __GFP_DMA to be consistent and cover
> >> all corner cases.
> > Yes, the test is not complete. If we really wanted this to be
> > accurate, we'd need to check that GFP_* exactly matches SLAB_CACHE_*.
> >
> > The only problem with dropping this is test that we should restore
> > GFP_DMA32 warning/errors somewhere else (as Christopher pointed out
> > here: https://lkml.org/lkml/2018/11/22/430), especially for kmalloc
> > case.
>
> I meant just dropping that patch hunk, not the whole test. Then the test
> stays as it is and will keep warning anyone calling kmalloc(GFP_DMA32).
> It would also warn anyone calling kmem_cache_alloc(GFP_DMA32) on
> SLAB_CACHE_DMA32 cache, but since the gfp can be just dropped, and you
> as the only user of this so far will do that, it's fine?

I missed your point, this would work fine indeed.

Thanks.

> > Maybe this can be done in kmalloc_slab.