Re: [PATCH v2] mm/huge_memory: prevent THP_ZERO_PAGE_ALLOC increased twice

[Liu Shixin]

On 2022/9/8 21:25, Kirill A. Shutemov wrote:
> On Thu, Sep 08, 2022 at 09:07:04PM +0800, Liu Shixin wrote:
>>
>> On 2022/9/8 20:31, Kirill A. Shutemov wrote:
>>> On Thu, Sep 08, 2022 at 11:55:33AM +0800, Liu Shixin wrote:
>>>> If two or more threads call get_huge_zero_page concurrently,
>>>> THP_ZERO_PAGE_ALLOC may increased two or more times. But actually,
>>>> this should only count as once since the extra zero pages has been
>>>> freed. Redefine its meaning to indicate the times a huge zero page
>>>> used for thp is successfully allocated.
>>> I don't particularly care, but it is not obvoius why the new behaviour is
>>> better.
>> The user who read the value may be more concerned about the huge zero
>> pages that are really allocated using for thp and can indicated the
>> times of calling huge_zero_page_shrinker.
>> I misunderstood when I first saw it.
> Please, explain the motivation in the commit message.
Thanks, I add the motivation.
https://lore.kernel.org/all/20220909021653.3371879-1-liushixin2@xxxxxxxxxx/