cgroup, memcg: move cgroup->event_list[_lock] and event callbacks into memcg
cgroup_event is being moved from cgroup core to memcg and the
implementation is already moved by the previous patch. This patch
moves the data fields and callbacks.
* cgroup->event_list[_lock] are moved to mem_cgroup.
* cftype->[un]register_event() are moved to cgroup_event. This makes
it impossible for individual cftype definitions to specify their
event callbacks. This is worked around by simply hard-coding
filename to event callback mapping in cgroup_write_event_control().
This is awkward and inflexible, which is actually desirable given
that we don't want to grow more usages of this feature.
* eventfd_ctx declaration is removed from cgroup.h, which makes
vmpressure.h miss eventfd_ctx declaration. Include eventfd.h from
vmpressure.h.
v2: Use file name from dentry instead of cftype. This will allow
removing all cftype handling in the function.
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>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d003681..2fcacb1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -249,6 +249,22 @@
*/
struct list_head list;
/*
+ * register_event() callback will be used to add new userspace
+ * waiter for changes related to this event. Use eventfd_signal()
+ * 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);
+ /*
+ * 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
* userspace closes eventfd.
*/
@@ -362,6 +378,10 @@
atomic_t numainfo_updating;
#endif
+ /* List of events which userspace want to receive */
+ struct list_head event_list;
+ spinlock_t event_list_lock;
+
struct mem_cgroup_per_node *nodeinfo[0];
/* WARNING: nodeinfo must be the last member here */
};
@@ -5992,7 +6012,7 @@
remove_wait_queue(event->wqh, &event->wait);
- event->cft->unregister_event(css, event->cft, event->eventfd);
+ event->unregister_event(css, event->cft, event->eventfd);
/* Notify userspace the event is going away. */
eventfd_signal(event->eventfd, 1);
@@ -6012,7 +6032,7 @@
{
struct cgroup_event *event = container_of(wait,
struct cgroup_event, wait);
- struct cgroup *cgrp = event->css->cgroup;
+ struct mem_cgroup *memcg = mem_cgroup_from_css(event->css);
unsigned long flags = (unsigned long)key;
if (flags & POLLHUP) {
@@ -6025,7 +6045,7 @@
* side will require wqh->lock via remove_wait_queue(),
* which we hold.
*/
- spin_lock(&cgrp->event_list_lock);
+ spin_lock(&memcg->event_list_lock);
if (!list_empty(&event->list)) {
list_del_init(&event->list);
/*
@@ -6034,7 +6054,7 @@
*/
schedule_work(&event->remove);
}
- spin_unlock(&cgrp->event_list_lock);
+ spin_unlock(&memcg->event_list_lock);
}
return 0;
@@ -6059,12 +6079,13 @@
static int cgroup_write_event_control(struct cgroup_subsys_state *css,
struct cftype *cft, const char *buffer)
{
- struct cgroup *cgrp = css->cgroup;
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct cgroup_event *event;
struct cgroup_subsys_state *cfile_css;
unsigned int efd, cfd;
struct fd efile;
struct fd cfile;
+ const char *name;
char *endp;
int ret;
@@ -6119,6 +6140,31 @@
}
/*
+ * Determine the event callbacks and set them in @event. This used
+ * 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.
+ */
+ name = cfile.file->f_dentry->d_name.name;
+
+ if (!strcmp(name, "memory.usage_in_bytes")) {
+ event->register_event = mem_cgroup_usage_register_event;
+ event->unregister_event = mem_cgroup_usage_unregister_event;
+ } else if (!strcmp(name, "memory.oom_control")) {
+ event->register_event = mem_cgroup_oom_register_event;
+ event->unregister_event = mem_cgroup_oom_unregister_event;
+ } else if (!strcmp(name, "memory.pressure_level")) {
+ 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;
+ } else {
+ ret = -EINVAL;
+ goto out_put_cfile;
+ }
+
+ /*
* Verify @cfile should belong to @css. Also, remaining events are
* automatically removed on cgroup destruction but the removal is
* asynchronous, so take an extra ref on @css.
@@ -6135,21 +6181,15 @@
if (ret)
goto out_put_cfile;
- if (!event->cft->register_event || !event->cft->unregister_event) {
- ret = -EINVAL;
- goto out_put_css;
- }
-
- ret = event->cft->register_event(css, event->cft,
- event->eventfd, buffer);
+ ret = event->register_event(css, event->cft, event->eventfd, buffer);
if (ret)
goto out_put_css;
efile.file->f_op->poll(efile.file, &event->pt);
- spin_lock(&cgrp->event_list_lock);
- list_add(&event->list, &cgrp->event_list);
- spin_unlock(&cgrp->event_list_lock);
+ spin_lock(&memcg->event_list_lock);
+ list_add(&event->list, &memcg->event_list);
+ spin_unlock(&memcg->event_list_lock);
fdput(cfile);
fdput(efile);
@@ -6175,8 +6215,6 @@
.name = "usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
.read = mem_cgroup_read,
- .register_event = mem_cgroup_usage_register_event,
- .unregister_event = mem_cgroup_usage_unregister_event,
},
{
.name = "max_usage_in_bytes",
@@ -6236,14 +6274,10 @@
.name = "oom_control",
.read_map = mem_cgroup_oom_control_read,
.write_u64 = mem_cgroup_oom_control_write,
- .register_event = mem_cgroup_oom_register_event,
- .unregister_event = mem_cgroup_oom_unregister_event,
.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
},
{
.name = "pressure_level",
- .register_event = vmpressure_register_event,
- .unregister_event = vmpressure_unregister_event,
},
#ifdef CONFIG_NUMA
{
@@ -6291,8 +6325,6 @@
.name = "memsw.usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
.read = mem_cgroup_read,
- .register_event = mem_cgroup_usage_register_event,
- .unregister_event = mem_cgroup_usage_unregister_event,
},
{
.name = "memsw.max_usage_in_bytes",
@@ -6483,6 +6515,8 @@
mutex_init(&memcg->thresholds_lock);
spin_lock_init(&memcg->move_lock);
vmpressure_init(&memcg->vmpressure);
+ INIT_LIST_HEAD(&memcg->event_list);
+ spin_lock_init(&memcg->event_list_lock);
return &memcg->css;
@@ -6555,7 +6589,6 @@
static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
- struct cgroup *cgrp = css->cgroup;
struct cgroup_event *event, *tmp;
/*
@@ -6563,12 +6596,12 @@
* Notify userspace about cgroup removing only after rmdir of cgroup
* directory to avoid race between userspace and kernelspace.
*/
- spin_lock(&cgrp->event_list_lock);
- list_for_each_entry_safe(event, tmp, &cgrp->event_list, list) {
+ spin_lock(&memcg->event_list_lock);
+ list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
list_del_init(&event->list);
schedule_work(&event->remove);
}
- spin_unlock(&cgrp->event_list_lock);
+ spin_unlock(&memcg->event_list_lock);
kmem_cgroup_css_offline(memcg);