memcg: remove cgroup_event->cft

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@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>

diff --git a/include/linux/vmpressure.h b/include/linux/vmpressure.h
index 9dd1914..b048365 100644 (file)
--- a/include/linux/vmpressure.h
+++ b/include/linux/vmpressure.h
@@ -36,11 +36,9 @@ 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 2fcacb1..3c93dcf 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -237,10 +237,6 @@ 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;
@@ -254,15 +250,13 @@ 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
@@ -5688,13 +5682,12 @@ 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;
 
@@ -5771,13 +5764,24 @@ 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;
 
@@ -5850,14 +5854,24 @@ 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;
@@ -5876,13 +5890,10 @@ 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);
 
@@ -6012,7 +6023,7 @@ 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);
@@ -6133,12 +6144,6 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
        if (ret < 0)
                goto out_put_cfile;
 
-       event->cft = __file_cft(cfile.file);
-       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
@@ -6157,8 +6162,8 @@ 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;
@@ -6181,7 +6186,7 @@ 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 e0f6283..0f25a99 100644 (file)
--- 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);