Re: [PATCH V2] mm/hugetlb: remove unnecessary holding of hugetlb_lock

[Ge Yang <yangge1116@126.com>]

在 2025/6/6 9:12, Andrew Morton 写道:
> On Thu, 5 Jun 2025 08:44:09 +0800 Ge Yang <yangge1116@126.com> wrote:
> 
>>> This change addresses a possible performance issue which was introduced
>>> by 113ed54ad276 ("mm/hugetlb: fix kernel NULL pointer dereference when
>>> replacing free hugetlb folios").  113ed54ad276 was added recently and
>>> was cc:stable.
>>>
>>> David said:
>>> https://lkml.kernel.org/r/87521d93-cc03-480d-a2ef-3ef8c84481c9@redhat.com
>>>
>>>
>>> Question is, will that bugfix's performance impact be sufficiently
>>> serious for us to also backport this new patch?
>>
>> In some low-probability scenarios, there could be severe impacts. For
>> example, when multiple CPUs execute the replace_free_hugepage_folios()
>> function simultaneously. It seems that we need to backport this new
>> patch. Thank you.
> 
> OK, thanks.  I added
> 
> Fixes: 113ed54ad276 ("mm/hugetlb: fix kernel NULL pointer dereference when replacing free hugetlb folios")
> Cc: <stable@vger.kernel.org>
> 
> and moved this to the mm-hotfixes pile.  I'll keep it there for a week
> or two for review/test.  Once it goes upstream, this should propagate
> into 6.15.x.

Ok，thanks.