Re: [PATCH 04/23] hugetlb_cgroup: pass around @hugetlb_cgroup instead of @cgroup

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Tejun Heo <tj@kernel.org> writes:

> cgroup controller API will be converted to primarily use struct
> cgroup_subsys_state instead of struct cgroup.  In preparation, make
> hugetlb_cgroup functions pass around struct hugetlb_cgroup instead of
> struct cgroup.
>
> This patch shouldn't cause any behavior differences.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Michal Hocko <mhocko@suse.cz>
> Cc: Johannes Weiner <hannes@cmpxchg.org>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>


> ---
>  mm/hugetlb_cgroup.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index 50f213f..d2f9fc0 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -56,17 +56,19 @@ static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
>  	return (h_cg == root_h_cgroup);
>  }
>
> -static inline struct hugetlb_cgroup *parent_hugetlb_cgroup(struct cgroup *cg)
> +static inline struct hugetlb_cgroup *
> +parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg)
>  {
> -	if (!cg->parent)
> +	struct cgroup *parent = h_cg->css.cgroup->parent;
> +
> +	if (!parent)
>  		return NULL;
> -	return hugetlb_cgroup_from_cgroup(cg->parent);
> +	return hugetlb_cgroup_from_cgroup(parent);
>  }
>
> -static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
> +static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
>  {
>  	int idx;
> -	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
>
>  	for (idx = 0; idx < hugetlb_max_hstate; idx++) {
>  		if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
> @@ -115,15 +117,14 @@ static void hugetlb_cgroup_css_free(struct cgroup *cgroup)
>   * page reference and test for page active here. This function
>   * cannot fail.
>   */
> -static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,
> +static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg,
>  				       struct page *page)
>  {
>  	int csize;
>  	struct res_counter *counter;
>  	struct res_counter *fail_res;
>  	struct hugetlb_cgroup *page_hcg;
> -	struct hugetlb_cgroup *h_cg   = hugetlb_cgroup_from_cgroup(cgroup);
> -	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);
> +	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
>
>  	page_hcg = hugetlb_cgroup_from_page(page);
>  	/*
> @@ -155,6 +156,7 @@ out:
>   */
>  static void hugetlb_cgroup_css_offline(struct cgroup *cgroup)
>  {
> +	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
>  	struct hstate *h;
>  	struct page *page;
>  	int idx = 0;
> @@ -163,13 +165,13 @@ static void hugetlb_cgroup_css_offline(struct cgroup *cgroup)
>  		for_each_hstate(h) {
>  			spin_lock(&hugetlb_lock);
>  			list_for_each_entry(page, &h->hugepage_activelist, lru)
> -				hugetlb_cgroup_move_parent(idx, cgroup, page);
> +				hugetlb_cgroup_move_parent(idx, h_cg, page);
>
>  			spin_unlock(&hugetlb_lock);
>  			idx++;
>  		}
>  		cond_resched();
> -	} while (hugetlb_cgroup_have_usage(cgroup));
> +	} while (hugetlb_cgroup_have_usage(h_cg));
>  }
>
>  int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
> -- 
> 1.8.3.1