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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: David Rientjes <rientjes@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
        Michal Hocko <mhocko@suse.cz>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [patch] mm, hugetlb_cgroup: align hugetlb cgroup limit to hugepage size
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Date: Fri, 08 Aug 2014 11:17:37 +0530
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David Rientjes <rientjes@google.com> writes:

> 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@google.com>
> ---
>  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));

you can use  1UL << huge_page_shift(hstate); ?

>  		ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
>  		break;
>  	default:
>

-aneesh