diff options
| -rw-r--r-- | Documentation/cgroups/cgroups.txt | 20 | ||||
| -rw-r--r-- | mm/memcontrol.c | 57 |
2 files changed, 37 insertions, 40 deletions
diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index 638bf17ff869..821de56d1580 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -24,7 +24,6 @@ CONTENTS: 2.1 Basic Usage 2.2 Attaching processes 2.3 Mounting hierarchies by name - 2.4 Notification API 3. Kernel API 3.1 Overview 3.2 Synchronization @@ -472,25 +471,6 @@ you give a subsystem a name. The name of the subsystem appears as part of the hierarchy description in /proc/mounts and /proc/<pid>/cgroups. -2.4 Notification API --------------------- - -There is mechanism which allows to get notifications about changing -status of a cgroup. - -To register a new notification handler you need to: - - create a file descriptor for event notification using eventfd(2); - - open a control file to be monitored (e.g. memory.usage_in_bytes); - - write "<event_fd> <control_fd> <args>" to cgroup.event_control. - Interpretation of args is defined by control file implementation; - -eventfd will be woken up by control file implementation or when the -cgroup is removed. - -To unregister a notification handler just close eventfd. - -NOTE: Support of notifications should be implemented for the control -file. See documentation for the subsystem. 3. Kernel API ============= diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 42f2843af1a7..ec8582b3a232 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -231,7 +231,7 @@ struct mem_cgroup_eventfd_list { /* * cgroup_event represents events which userspace want to receive. */ -struct cgroup_event { +struct mem_cgroup_event { /* * memcg which the event belongs to. */ @@ -6002,14 +6002,27 @@ static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) #endif /* + * DO NOT USE IN NEW FILES. + * + * "cgroup.event_control" implementation. + * + * This is way over-engineered. It tries to support fully configurable + * events for each user. Such level of flexibility is completely + * unnecessary especially in the light of the planned unified hierarchy. + * + * Please deprecate this and replace with something simpler if at all + * possible. + */ + +/* * Unregister event and free resources. * * Gets called from workqueue. */ -static void cgroup_event_remove(struct work_struct *work) +static void memcg_event_remove(struct work_struct *work) { - struct cgroup_event *event = container_of(work, struct cgroup_event, - remove); + struct mem_cgroup_event *event = + container_of(work, struct mem_cgroup_event, remove); struct mem_cgroup *memcg = event->memcg; remove_wait_queue(event->wqh, &event->wait); @@ -6029,11 +6042,11 @@ static void cgroup_event_remove(struct work_struct *work) * * Called with wqh->lock held and interrupts disabled. */ -static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, - int sync, void *key) +static int memcg_event_wake(wait_queue_t *wait, unsigned mode, + int sync, void *key) { - struct cgroup_event *event = container_of(wait, - struct cgroup_event, wait); + struct mem_cgroup_event *event = + container_of(wait, struct mem_cgroup_event, wait); struct mem_cgroup *memcg = event->memcg; unsigned long flags = (unsigned long)key; @@ -6062,27 +6075,29 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, return 0; } -static void cgroup_event_ptable_queue_proc(struct file *file, +static void memcg_event_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, poll_table *pt) { - struct cgroup_event *event = container_of(pt, - struct cgroup_event, pt); + struct mem_cgroup_event *event = + container_of(pt, struct mem_cgroup_event, pt); event->wqh = wqh; add_wait_queue(wqh, &event->wait); } /* + * DO NOT USE IN NEW FILES. + * * Parse input and register new cgroup event handler. * * Input must be in format '<event_fd> <control_fd> <args>'. * Interpretation of args is defined by control file implementation. */ -static int cgroup_write_event_control(struct cgroup_subsys_state *css, - struct cftype *cft, const char *buffer) +static int memcg_write_event_control(struct cgroup_subsys_state *css, + struct cftype *cft, const char *buffer) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); - struct cgroup_event *event; + struct mem_cgroup_event *event; struct cgroup_subsys_state *cfile_css; unsigned int efd, cfd; struct fd efile; @@ -6107,9 +6122,9 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, event->memcg = memcg; INIT_LIST_HEAD(&event->list); - init_poll_funcptr(&event->pt, cgroup_event_ptable_queue_proc); - init_waitqueue_func_entry(&event->wait, cgroup_event_wake); - INIT_WORK(&event->remove, cgroup_event_remove); + init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc); + init_waitqueue_func_entry(&event->wait, memcg_event_wake); + INIT_WORK(&event->remove, memcg_event_remove); efile = fdget(efd); if (!efile.file) { @@ -6140,6 +6155,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, * to be done via struct cftype but cgroup core no longer knows * about these events. The following is crude but the whole thing * is for compatibility anyway. + * + * DO NOT ADD NEW FILES. */ name = cfile.file->f_dentry->d_name.name; @@ -6251,8 +6268,8 @@ static struct cftype mem_cgroup_files[] = { .read_u64 = mem_cgroup_hierarchy_read, }, { - .name = "cgroup.event_control", - .write_string = cgroup_write_event_control, + .name = "cgroup.event_control", /* XXX: for compat */ + .write_string = memcg_write_event_control, .flags = CFTYPE_NO_PREFIX, .mode = S_IWUGO, }, @@ -6585,7 +6602,7 @@ static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); - struct cgroup_event *event, *tmp; + struct mem_cgroup_event *event, *tmp; /* * Unregister events and notify userspace. |