2021-02-02 11:06:59

by Xu, Yanfei

Subject: [PATCH v2] mm/hugetlb: remove redundant check in preparing and destroying gigantic page

From: Yanfei Xu <[email protected]>

Gigantic page is a compound page and its order is more than 1.
Thus it must be available for hpage_pincount. Let's remove the
redundant check for gigantic page.

Signed-off-by: Yanfei Xu <[email protected]>
---
mm/hugetlb.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a3e4fa2c5e94..dac5db569ccb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1219,8 +1219,7 @@ static void destroy_compound_gigantic_page(struct page *page,
struct page *p = page + 1;

atomic_set(compound_mapcount_ptr(page), 0);
- if (hpage_pincount_available(page))
- atomic_set(compound_pincount_ptr(page), 0);
+ atomic_set(compound_pincount_ptr(page), 0);

for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
clear_compound_head(p);
@@ -1501,9 +1500,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order)
set_compound_head(p, page);
}
atomic_set(compound_mapcount_ptr(page), -1);
-
- if (hpage_pincount_available(page))
- atomic_set(compound_pincount_ptr(page), 0);
+ atomic_set(compound_pincount_ptr(page), 0);
}

/*
--
2.27.0

2021-02-02 12:21:44

by Xu, Yanfei

Subject: Re: [PATCH v2] mm/hugetlb: remove redundant check in preparing and destroying gigantic page

I'm sorry for forgetting to add David.
Now add David ：）

Thanks，
Yanfei

On 2/2/21 7:20 PM, [email protected] wrote:
> From: Yanfei Xu <[email protected]>
>
> Gigantic page is a compound page and its order is more than 1.
> Thus it must be available for hpage_pincount. Let's remove the
> redundant check for gigantic page.
>
> Signed-off-by: Yanfei Xu <[email protected]>
> ---
> mm/hugetlb.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index a3e4fa2c5e94..dac5db569ccb 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1219,8 +1219,7 @@ static void destroy_compound_gigantic_page(struct page *page,
> struct page *p = page + 1;
>
> atomic_set(compound_mapcount_ptr(page), 0);
> - if (hpage_pincount_available(page))
> - atomic_set(compound_pincount_ptr(page), 0);
> + atomic_set(compound_pincount_ptr(page), 0);
>
> for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
> clear_compound_head(p);
> @@ -1501,9 +1500,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order)
> set_compound_head(p, page);
> }
> atomic_set(compound_mapcount_ptr(page), -1);
> -
> - if (hpage_pincount_available(page))
> - atomic_set(compound_pincount_ptr(page), 0);
> + atomic_set(compound_pincount_ptr(page), 0);
> }
>
> /*
>

2021-02-03 00:52:06

by Mike Kravetz

Subject: Re: [PATCH v2] mm/hugetlb: remove redundant check in preparing and destroying gigantic page

On 2/2/21 4:19 AM, Xu, Yanfei wrote:
> I'm sorry for forgetting to add David.
> Now add David ：）
>
> Thanks，
> Yanfei
>
> On 2/2/21 7:20 PM, [email protected] wrote:
>> From: Yanfei Xu <[email protected]>
>>
>> Gigantic page is a compound page and its order is more than 1.
>> Thus it must be available for hpage_pincount. Let's remove the
>> redundant check for gigantic page.
>>
>> Signed-off-by: Yanfei Xu <[email protected]>
>> ---
>> mm/hugetlb.c | 7 ++-----
>> 1 file changed, 2 insertions(+), 5 deletions(-)

I can not imagine a 'hugetlb gigantic page' being <= 1 order, so this change
makes sense. Thanks,

Reviewed-by: Mike Kravetz <[email protected]>
--
Mike Kravetz

>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index a3e4fa2c5e94..dac5db569ccb 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -1219,8 +1219,7 @@ static void destroy_compound_gigantic_page(struct page *page,
>> struct page *p = page + 1;
>> atomic_set(compound_mapcount_ptr(page), 0);
>> - if (hpage_pincount_available(page))
>> - atomic_set(compound_pincount_ptr(page), 0);
>> + atomic_set(compound_pincount_ptr(page), 0);
>> for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
>> clear_compound_head(p);
>> @@ -1501,9 +1500,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order)
>> set_compound_head(p, page);
>> }
>> atomic_set(compound_mapcount_ptr(page), -1);
>> -
>> - if (hpage_pincount_available(page))
>> - atomic_set(compound_pincount_ptr(page), 0);
>> + atomic_set(compound_pincount_ptr(page), 0);
>> }
>> /*
>>
>

2021-02-05 08:20:52

by David Hildenbrand

Subject: Re: [PATCH v2] mm/hugetlb: remove redundant check in preparing and destroying gigantic page

On 02.02.21 12:20, [email protected] wrote:
> From: Yanfei Xu <[email protected]>
>
> Gigantic page is a compound page and its order is more than 1.
> Thus it must be available for hpage_pincount. Let's remove the
> redundant check for gigantic page.
>
> Signed-off-by: Yanfei Xu <[email protected]>
> ---
> mm/hugetlb.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index a3e4fa2c5e94..dac5db569ccb 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1219,8 +1219,7 @@ static void destroy_compound_gigantic_page(struct page *page,
> struct page *p = page + 1;
>
> atomic_set(compound_mapcount_ptr(page), 0);
> - if (hpage_pincount_available(page))
> - atomic_set(compound_pincount_ptr(page), 0);
> + atomic_set(compound_pincount_ptr(page), 0);
>
> for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
> clear_compound_head(p);
> @@ -1501,9 +1500,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned int order)
> set_compound_head(p, page);
> }
> atomic_set(compound_mapcount_ptr(page), -1);
> -
> - if (hpage_pincount_available(page))
> - atomic_set(compound_pincount_ptr(page), 0);
> + atomic_set(compound_pincount_ptr(page), 0);
> }
>
> /*
>

Reviewed-by: David Hildenbrand <[email protected]>

--
Thanks,

David / dhildenb