Re: [PATCH v2] mm/hugetlb: remove redundant reservation check condition in alloc_huge_page()

[Mike Kravetz]

On 3/1/21 2:47 AM, Miaohe Lin wrote:
> vma_resv_map(vma) checks if a reserve map is associated with the vma.  The
> routine vma_needs_reservation() will check vma_resv_map(vma) and return 1
> if no reserv map is present.  map_chg is set to the return value of
> vma_needs_reservation().  Therefore, !vma_resv_map(vma) is redundant in the
> expression:
>   map_chg || avoid_reserve || !vma_resv_map(vma);
> Remove the redundant check.
> 
> [Thanks Mike Kravetz for reshaping this commit message!]
> 
> Signed-off-by: Miaohe Lin 

Thanks,

Reviewed-by: Mike Kravetz 

> ---
>  mm/hugetlb.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 60c67eb016f7..060005b868cf 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2314,7 +2314,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
>  
>   /* If this allocation is not consuming a reservation, charge it now.
>*/
> - deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
> + deferred_reserve = map_chg || avoid_reserve;
>   if (deferred_reserve) {
>   ret = hugetlb_cgroup_charge_cgroup_rsvd(
>   idx, pages_per_huge_page(h), _cg);
> 

[PATCH v2] mm/hugetlb: remove redundant reservation check condition in alloc_huge_page()

[Miaohe Lin]

vma_resv_map(vma) checks if a reserve map is associated with the vma.  The
routine vma_needs_reservation() will check vma_resv_map(vma) and return 1
if no reserv map is present.  map_chg is set to the return value of
vma_needs_reservation().  Therefore, !vma_resv_map(vma) is redundant in the
expression:
map_chg || avoid_reserve || !vma_resv_map(vma);
Remove the redundant check.

[Thanks Mike Kravetz for reshaping this commit message!]

Signed-off-by: Miaohe Lin 
---
 mm/hugetlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 60c67eb016f7..060005b868cf 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2314,7 +2314,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
 
/* If this allocation is not consuming a reservation, charge it now.
 */
-   deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
+   deferred_reserve = map_chg || avoid_reserve;
if (deferred_reserve) {
ret = hugetlb_cgroup_charge_cgroup_rsvd(
idx, pages_per_huge_page(h), _cg);
-- 
2.19.1