On Thu 15-08-13 12:02:27, Tejun Heo wrote:
> The only use of cgroup_event->cft is distinguishing "usage_in_bytes"
> and "memsw.usgae_in_bytes" for mem_cgroup_usage_[un]register_event(),
> which can be done by adding an explicit argument to the function and
> implementing two wrappers so that the two cases can be distinguished
> from the function alone.
>
> Remove cgroup_event->cft and the related code including
> [un]register_events() methods.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
> ---
> include/linux/vmpressure.h | 2 --
> mm/memcontrol.c | 65 +++++++++++++++++++++++++---------------------
> mm/vmpressure.c | 14 +++-------
> 3 files changed, 38 insertions(+), 43 deletions(-)
>
> diff --git a/include/linux/vmpressure.h b/include/linux/vmpressure.h
> index 324ea7a..dd0b025 100644
> --- a/include/linux/vmpressure.h
> +++ b/include/linux/vmpressure.h
> @@ -35,11 +35,9 @@ extern struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg);
> extern struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr);
> extern struct vmpressure *css_to_vmpressure(struct cgroup_subsys_state *css);
> extern int vmpressure_register_event(struct cgroup_subsys_state *css,
> - struct cftype *cft,
> struct eventfd_ctx *eventfd,
> const char *args);
> extern void vmpressure_unregister_event(struct cgroup_subsys_state *css,
> - struct cftype *cft,
> struct eventfd_ctx *eventfd);
> #else
> static inline void vmpressure(gfp_t gfp, struct mem_cgroup *memcg,
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 9b833e1..18e98ae 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -249,10 +249,6 @@ struct cgroup_event {
> */
> struct cgroup_subsys_state *css;
> /*
> - * Control file which the event associated.
> - */
> - struct cftype *cft;
> - /*
> * eventfd to signal userspace about the event.
> */
> struct eventfd_ctx *eventfd;
> @@ -266,15 +262,13 @@ struct cgroup_event {
> * on eventfd to send notification to userspace.
> */
> int (*register_event)(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct eventfd_ctx *eventfd,
> - const char *args);
> + struct eventfd_ctx *eventfd, const char *args);
> /*
> * unregister_event() callback will be called when userspace closes
> * the eventfd or on cgroup removing. This callback must be set,
> * if you want provide notification functionality.
> */
> void (*unregister_event)(struct cgroup_subsys_state *css,
> - struct cftype *cft,
> struct eventfd_ctx *eventfd);
> /*
> * All fields below needed to unregister event when
> @@ -5659,13 +5653,12 @@ static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
> mem_cgroup_oom_notify_cb(iter);
> }
>
> -static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
> +static int __mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
> + struct eventfd_ctx *eventfd, const char *args, enum res_type type)
> {
> struct mem_cgroup *memcg = mem_cgroup_from_css(css);
> struct mem_cgroup_thresholds *thresholds;
> struct mem_cgroup_threshold_ary *new;
> - enum res_type type = MEMFILE_TYPE(cft->private);
> u64 threshold, usage;
> int i, size, ret;
>
> @@ -5742,13 +5735,24 @@ unlock:
> return ret;
> }
>
> -static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct eventfd_ctx *eventfd)
> +static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
> + struct eventfd_ctx *eventfd, const char *args)
> +{
> + return __mem_cgroup_usage_register_event(css, eventfd, args, _MEM);
> +}
> +
> +static int memsw_cgroup_usage_register_event(struct cgroup_subsys_state *css,
> + struct eventfd_ctx *eventfd, const char *args)
> +{
> + return __mem_cgroup_usage_register_event(css, eventfd, args, _MEMSWAP);
> +}
> +
> +static void __mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
> + struct eventfd_ctx *eventfd, enum res_type type)
> {
> struct mem_cgroup *memcg = mem_cgroup_from_css(css);
> struct mem_cgroup_thresholds *thresholds;
> struct mem_cgroup_threshold_ary *new;
> - enum res_type type = MEMFILE_TYPE(cft->private);
> u64 usage;
> int i, j, size;
>
> @@ -5821,14 +5825,24 @@ unlock:
> mutex_unlock(&memcg->thresholds_lock);
> }
>
> +static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
> + struct eventfd_ctx *eventfd)
> +{
> + return __mem_cgroup_usage_unregister_event(css, eventfd, _MEM);
> +}
> +
> +static void memsw_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
> + struct eventfd_ctx *eventfd)
> +{
> + return __mem_cgroup_usage_unregister_event(css, eventfd, _MEMSWAP);
> +}
> +
> static int mem_cgroup_oom_register_event(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
> + struct eventfd_ctx *eventfd, const char *args)
> {
> struct mem_cgroup *memcg = mem_cgroup_from_css(css);
> struct mem_cgroup_eventfd_list *event;
> - enum res_type type = MEMFILE_TYPE(cft->private);
>
> - BUG_ON(type != _OOM_TYPE);
> event = kmalloc(sizeof(*event), GFP_KERNEL);
> if (!event)
> return -ENOMEM;
> @@ -5847,13 +5861,10 @@ static int mem_cgroup_oom_register_event(struct cgroup_subsys_state *css,
> }
>
> static void mem_cgroup_oom_unregister_event(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct eventfd_ctx *eventfd)
> + struct eventfd_ctx *eventfd)
> {
> struct mem_cgroup *memcg = mem_cgroup_from_css(css);
> struct mem_cgroup_eventfd_list *ev, *tmp;
> - enum res_type type = MEMFILE_TYPE(cft->private);
> -
> - BUG_ON(type != _OOM_TYPE);
>
> spin_lock(&memcg_oom_lock);
>
> @@ -5983,7 +5994,7 @@ static void cgroup_event_remove(struct work_struct *work)
>
> remove_wait_queue(event->wqh, &event->wait);
>
> - event->unregister_event(css, event->cft, event->eventfd);
> + event->unregister_event(css, event->eventfd);
>
> /* Notify userspace the event is going away. */
> eventfd_signal(event->eventfd, 1);
> @@ -6104,12 +6115,6 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
> if (ret < 0)
> goto out_put_cfile;
>
> - event->cft = __file_cft(cfile);
> - if (IS_ERR(event->cft)) {
> - ret = PTR_ERR(event->cft);
> - goto out_put_cfile;
> - }
> -
> /*
> * Determine the event callbacks and set them in @event. This used
> * to be done via struct cftype but cgroup core no longer knows
> @@ -6128,8 +6133,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
> event->register_event = vmpressure_register_event;
> event->unregister_event = vmpressure_unregister_event;
> } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
> - event->register_event = mem_cgroup_usage_register_event;
> - event->unregister_event = mem_cgroup_usage_unregister_event;
> + event->register_event = memsw_cgroup_usage_register_event;
> + event->unregister_event = memsw_cgroup_usage_unregister_event;
> } else {
> ret = -EINVAL;
> goto out_put_cfile;
> @@ -6151,7 +6156,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
> if (ret)
> goto out_put_cfile;
>
> - ret = event->register_event(css, event->cft, event->eventfd, buffer);
> + ret = event->register_event(css, event->eventfd, buffer);
> if (ret)
> goto out_put_css;
>
> diff --git a/mm/vmpressure.c b/mm/vmpressure.c
> index 13489b1..40ed6e8 100644
> --- a/mm/vmpressure.c
> +++ b/mm/vmpressure.c
> @@ -279,7 +279,6 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
> /**
> * vmpressure_register_event() - Bind vmpressure notifications to an eventfd
> * @css: css that is interested in vmpressure notifications
> - * @cft: cgroup control files handle
> * @eventfd: eventfd context to link notifications with
> * @args: event arguments (used to set up a pressure level threshold)
> *
> @@ -289,13 +288,10 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
> * threshold (one of vmpressure_str_levels, i.e. "low", "medium", or
> * "critical").
> *
> - * This function should not be used directly, just pass it to (struct
> - * cftype).register_event, and then cgroup core will handle everything by
> - * itself.
> + * To be used as memcg event method.
> */
> int vmpressure_register_event(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct eventfd_ctx *eventfd,
> - const char *args)
> + struct eventfd_ctx *eventfd, const char *args)
> {
> struct vmpressure *vmpr = css_to_vmpressure(css);
> struct vmpressure_event *ev;
> @@ -326,19 +322,15 @@ int vmpressure_register_event(struct cgroup_subsys_state *css,
> /**
> * vmpressure_unregister_event() - Unbind eventfd from vmpressure
> * @css: css handle
> - * @cft: cgroup control files handle
> * @eventfd: eventfd context that was used to link vmpressure with the @cg
> *
> * This function does internal manipulations to detach the @eventfd from
> * the vmpressure notifications, and then frees internal resources
> * associated with the @eventfd (but the @eventfd itself is not freed).
> *
> - * This function should not be used directly, just pass it to (struct
> - * cftype).unregister_event, and then cgroup core will handle everything
> - * by itself.
> + * To be used as memcg event method.
> */
> void vmpressure_unregister_event(struct cgroup_subsys_state *css,
> - struct cftype *cft,
> struct eventfd_ctx *eventfd)
> {
> struct vmpressure *vmpr = css_to_vmpressure(css);
> --
> 1.8.3.1
>
--
Michal Hocko
SUSE Labs
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