Re: [PATCH v5 4/5] mm/sparse-vmemmap: improve memory savings for compound devmaps

[Joao Martins <joao.m.martins@oracle.com>]

On 2/12/22 10:08, Muchun Song wrote:
> On Fri, Feb 11, 2022 at 8:37 PM Joao Martins <joao.m.martins@oracle.com> wrote:
>> On 2/11/22 07:54, Muchun Song wrote:
>>> On Fri, Feb 11, 2022 at 3:34 AM Joao Martins <joao.m.martins@oracle.com> wrote:
>>>> @@ -609,7 +624,8 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
>>>>  }
>>>>
>>>>  static int __meminit vmemmap_populate_address(unsigned long addr, int node,
>>>> -                                             struct vmem_altmap *altmap)
>>>> +                                             struct vmem_altmap *altmap,
>>>> +                                             struct page *reuse, struct page **page)
>>>
>>> We can remove the last argument (struct page **page) if we change
>>> the return type to "pte_t *".  More simple, don't you think?
>>
>> Hmmm, perhaps it is simpler, specially provided the only error code is ENOMEM.
>>
>> Albeit perhaps what we want is a `struct page *` rather than a pte.
> 
> The caller can extract `struct page` from a pte.
> 

Yeap, we do that here already. Anyway, I can try switching to the style you suggest
and see how it looks.