Re: [PATCH v3 2/6] mm/huge_memory: convert "tva_flags" to "enum tva_type"

[Baolin Wang <baolin.wang@linux.alibaba.com>]

On 2025/8/4 23:40, Usama Arif wrote:
> From: David Hildenbrand <david@redhat.com>
> 
> When determining which THP orders are eligible for a VMA mapping,
> we have previously specified tva_flags, however it turns out it is
> really not necessary to treat these as flags.
> 
> Rather, we distinguish between distinct modes.
> 
> The only case where we previously combined flags was with
> TVA_ENFORCE_SYSFS, but we can avoid this by observing that this
> is the default, except for MADV_COLLAPSE or an edge cases in
> collapse_pte_mapped_thp() and hugepage_vma_revalidate(), and
> adding a mode specifically for this case - TVA_FORCED_COLLAPSE.
> 
> We have:
> * smaps handling for showing "THPeligible"
> * Pagefault handling
> * khugepaged handling
> * Forced collapse handling: primarily MADV_COLLAPSE, but also for
>    an edge case in collapse_pte_mapped_thp()
> 
> Disregarding the edge cases, we only want to ignore sysfs settings only
> when we are forcing a collapse through MADV_COLLAPSE, otherwise we
> want to enforce it, hence this patch does the following flag to enum
> conversions:
> 
> * TVA_SMAPS | TVA_ENFORCE_SYSFS -> TVA_SMAPS
> * TVA_IN_PF | TVA_ENFORCE_SYSFS -> TVA_PAGEFAULT
> * TVA_ENFORCE_SYSFS             -> TVA_KHUGEPAGED
> * 0                             -> TVA_FORCED_COLLAPSE
> 
> With this change, we immediately know if we are in the forced collapse
> case, which will be valuable next.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> Acked-by: Usama Arif <usamaarif642@gmail.com>
> Signed-off-by: Usama Arif <usamaarif642@gmail.com>
> ---

Looks really nice. Thanks.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>