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

Vlastimil Babka
2018-12-06T09:37:44Z

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?

> Maybe this can be done in kmalloc_slab.