Re: [PATCH] mm/thp: Rename TRANSPARENT_HUGEPAGE_NEVER_DAX to _UNSUPPORTED

David Hildenbrand
2023-03-16T15:37:44Z

On 16.03.23 16:18, Peter Xu wrote:
> On Thu, Mar 16, 2023 at 03:57:12PM +0100, David Hildenbrand wrote:
>> On 15.03.23 18:16, Peter Xu wrote:
>>> TRANSPARENT_HUGEPAGE_NEVER_DAX has nothing to do with DAX. It's set when
>>> has_transparent_hugepage() returns false, checked in hugepage_vma_check()
>>> and will disable THP completely if false. Rename it to reflect its real
>>> purpose.
>>>
>>> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>>> Cc: Yang Shi <shy828301@gmail.com>
>>> Signed-off-by: Peter Xu <peterx@redhat.com>
>>> ---
>>> include/linux/huge_mm.h | 2 +-
>>> mm/huge_memory.c | 4 ++--
>>> 2 files changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
>>> index 70bd867eba94..9a3a3af2dd80 100644
>>> --- a/include/linux/huge_mm.h
>>> +++ b/include/linux/huge_mm.h
>>> @@ -79,7 +79,7 @@ static inline vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn,
>>> }
>>> enum transparent_hugepage_flag {
>>> - TRANSPARENT_HUGEPAGE_NEVER_DAX,
>>> + TRANSPARENT_HUGEPAGE_UNSUPPORTED,
>>> TRANSPARENT_HUGEPAGE_FLAG,
>>> TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
>>> TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>>> index b0ab247939e0..913e7dc32869 100644
>>> --- a/mm/huge_memory.c
>>> +++ b/mm/huge_memory.c
>>> @@ -88,7 +88,7 @@ bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags,
>>> /*
>>> * If the hardware/firmware marked hugepage support disabled.
>>> */
>>> - if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
>>> + if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED))
>>> return false;
>>> /* khugepaged doesn't collapse DAX vma, but page fault is fine. */
>>> @@ -464,7 +464,7 @@ static int __init hugepage_init(void)
>>> * Hardware doesn't support hugepages, hence disable
>>> * DAX PMD support.
>>
>>
>> We should also fixup that comment then, no?
>
> Yes, I'd drop the comment since the code explains itself. One fixup
> attached. Thanks.

LGTM

--
Thanks,

David / dhildenb