Re: [patch] mm, hugetlb_cgroup: align hugetlb cgroup limit to hugepage size

[Michal Hocko]

On Thu 07-08-14 13:34:12, David Rientjes wrote:
> Memcg aligns memory.limit_in_bytes to PAGE_SIZE as part of the resource counter
> since it makes no sense to allow a partial page to be charged.
> 
> As a result of the hugetlb cgroup using the resource counter, it is also aligned
> to PAGE_SIZE but makes no sense unless aligned to the size of the hugepage being
> limited.
> 
> Align hugetlb cgroup limit to hugepage size.
> 
> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>

huge_page_shift as proposed by Aneesh looks better.

Acked-by: Michal Hocko <mhocko@xxxxxxx>

> ---
>  mm/hugetlb_cgroup.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -275,6 +275,8 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
>  		ret = res_counter_memparse_write_strategy(buf, &val);
>  		if (ret)
>  			break;
> +		val = ALIGN(val, 1 << (huge_page_order(&hstates[idx]) +
> +				       PAGE_SHIFT));
>  		ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
>  		break;
>  	default:

-- 
Michal Hocko
SUSE Labs
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