On Mon 14-07-14 11:44:05, Tejun Heo wrote:
> Currently, cftypes added by cgroup_add_cftypes() are used for both the
> unified default hierarchy and legacy ones and subsystems can mark each
> file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to
> appear only on one of them. This is quite hairy and error-prone.
> Also, we may end up exposing interface files to the default hierarchy
> without thinking it through.
>
> cgroup_subsys will grow two separate cftype addition functions and
> apply each only on the hierarchies of the matching type. This will
> allow organizing cftypes in a lot clearer way and encourage subsystems
> to scrutinize the interface which is being exposed in the new default
> hierarchy.
>
> In preparation, this patch adds cgroup_add_legacy_cftypes() which
> currently is a simple wrapper around cgroup_add_cftypes() and replaces
> all cgroup_add_cftypes() usages with it.
>
> While at it, this patch drops a completely spurious return from
> __hugetlb_cgroup_file_init().
>
> This patch doesn't introduce any functional differences.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
> ---
> block/blk-cgroup.c | 3 ++-
> include/linux/cgroup.h | 2 +-
> kernel/cgroup.c | 7 ++++++-
> mm/hugetlb_cgroup.c | 5 ++---
> mm/memcontrol.c | 3 ++-
> net/ipv4/tcp_memcontrol.c | 2 +-
> 6 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index 5cfbc72..2541cf0 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -1124,7 +1124,8 @@ int __init blkcg_policy_register(struct blkcg_policy *pol)
>
> /* everything is in place, add intf files for the new policy */
> if (pol->cftypes)
> - WARN_ON(cgroup_add_cftypes(&blkio_cgrp_subsys, pol->cftypes));
> + WARN_ON(cgroup_add_legacy_cftypes(&blkio_cgrp_subsys,
> + pol->cftypes));
> ret = 0;
> out_unlock:
> mutex_unlock(&blkcg_pol_mutex);
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index a6e9c2e..f5f0fee 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -590,7 +590,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
>
> char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
>
> -int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
> +int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
> int cgroup_rm_cftypes(struct cftype *cfts);
>
> bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 6496a83..c275aa4 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -3170,7 +3170,7 @@ int cgroup_rm_cftypes(struct cftype *cfts)
> * function currently returns 0 as long as @cfts registration is successful
> * even if some file creation attempts on existing cgroups fail.
> */
> -int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
> +static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
> {
> int ret;
>
> @@ -3195,6 +3195,11 @@ int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
> return ret;
> }
>
> +int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
> +{
> + return cgroup_add_cftypes(ss, cfts);
> +}
> +
> /**
> * cgroup_task_count - count the number of tasks in a cgroup.
> * @cgrp: the cgroup in question
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index 493f758..9aae6f4 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -358,9 +358,8 @@ static void __init __hugetlb_cgroup_file_init(int idx)
> cft = &h->cgroup_files[4];
> memset(cft, 0, sizeof(*cft));
>
> - WARN_ON(cgroup_add_cftypes(&hugetlb_cgrp_subsys, h->cgroup_files));
> -
> - return;
> + WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
> + h->cgroup_files));
> }
>
> void __init hugetlb_cgroup_file_init(void)
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 8331f27..b6b3c6f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -7065,7 +7065,8 @@ __setup("swapaccount=", enable_swap_account);
>
> static void __init memsw_file_init(void)
> {
> - WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, memsw_cgroup_files));
> + WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
> + memsw_cgroup_files));
> }
>
> static void __init enable_swap_cgroup(void)
> diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
> index f7a2ec3..3af5226 100644
> --- a/net/ipv4/tcp_memcontrol.c
> +++ b/net/ipv4/tcp_memcontrol.c
> @@ -222,7 +222,7 @@ static struct cftype tcp_files[] = {
>
> static int __init tcp_memcontrol_init(void)
> {
> - WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, tcp_files));
> + WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, tcp_files));
> return 0;
> }
> __initcall(tcp_memcontrol_init);
> --
> 1.9.3
>
--
Michal Hocko
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe cgroups" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
