On Wed, 6 Apr 2016, David Rientjes wrote:
> The page_counter rounds limits down to page size values. This makes
> sense, except in the case of hugetlb_cgroup where it's not possible to
> charge partial hugepages.
>
> Round the hugetlb_cgroup limit down to hugepage size.
>
> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
May this be merged into -mm?
> ---
> mm/hugetlb_cgroup.c | 35 ++++++++++++++++++++++++++---------
> 1 file changed, 26 insertions(+), 9 deletions(-)
>
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -67,26 +67,42 @@ static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
> return false;
> }
>
> +static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup,
> + struct hugetlb_cgroup *parent_h_cgroup)
> +{
> + int idx;
> +
> + for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) {
> + struct page_counter *counter = &h_cgroup->hugepage[idx];
> + struct page_counter *parent = NULL;
> + unsigned long limit;
> + int ret;
> +
> + if (parent_h_cgroup)
> + parent = &parent_h_cgroup->hugepage[idx];
> + page_counter_init(counter, parent);
> +
> + limit = round_down(PAGE_COUNTER_MAX,
> + 1 << huge_page_order(&hstates[idx]));
> + ret = page_counter_limit(counter, limit);
> + VM_BUG_ON(ret);
> + }
> +}
> +
> static struct cgroup_subsys_state *
> hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
> {
> struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
> struct hugetlb_cgroup *h_cgroup;
> - int idx;
>
> h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
> if (!h_cgroup)
> return ERR_PTR(-ENOMEM);
>
> - if (parent_h_cgroup) {
> - for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
> - page_counter_init(&h_cgroup->hugepage[idx],
> - &parent_h_cgroup->hugepage[idx]);
> - } else {
> + if (!parent_h_cgroup)
> root_h_cgroup = h_cgroup;
> - for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
> - page_counter_init(&h_cgroup->hugepage[idx], NULL);
> - }
> +
> + hugetlb_cgroup_init(h_cgroup, parent_h_cgroup);
> return &h_cgroup->css;
> }
>
> @@ -285,6 +301,7 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
> return ret;
>
> idx = MEMFILE_IDX(of_cft(of)->private);
> + nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx]));
>
> switch (MEMFILE_ATTR(of_cft(of)->private)) {
> case RES_LIMIT:
>
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