cgroup, memcg: move cgroup_event implementation to memcg
cgroup_event is way over-designed and tries to build a generic
flexible event mechanism into cgroup - fully customizable event
specification for each user of the interface. This is utterly
unnecessary and overboard especially in the light of the planned
unified hierarchy as there's gonna be single agent. Simply generating
events at fixed points, or if that's too restrictive, configureable
cadence or single set of configureable points should be enough.
Thankfully, memcg is the only user and gets to keep it. Replacing it
with something simpler on sane_behavior is strongly recommended.
This patch moves cgroup_event and "cgroup.event_control"
implementation to mm/memcontrol.c. Clearing of events on cgroup
destruction is moved from cgroup_destroy_locked() to
mem_cgroup_css_offline(), which shouldn't make any noticeable
difference.
cgroup_css() and __file_cft() are exported to enable the move;
however, this will soon be reverted once the event code is updated to
be memcg specific.
Note that "cgroup.event_control" will now exist only on the hierarchy
with memcg attached to it. While this change is visible to userland,
it is unlikely to be noticeable as the file has never been meaningful
outside memcg.
Aside from the above change, this is pure code relocation.
v2: Per Li Zefan's comments, init/Kconfig updated accordingly and
poll.h inclusion moved from cgroup.c to memcontrol.c.
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/init/Kconfig b/init/Kconfig
index 3ecd8a1..3ca5b81 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -861,7 +861,6 @@
menuconfig CGROUPS
boolean "Control Group support"
- depends on EVENTFD
help
This option adds support for grouping sets of processes together, for
use with process control subsystems such as Cpusets, CFS, memory
@@ -928,6 +927,7 @@
bool "Memory Resource Controller for Control Groups"
depends on RESOURCE_COUNTERS
select MM_OWNER
+ select EVENTFD
help
Provides a memory resource controller that manages both anonymous
memory and page cache. (See Documentation/cgroups/memory.txt)
@@ -1167,7 +1167,6 @@
config SCHED_AUTOGROUP
bool "Automatic process group scheduling"
- select EVENTFD
select CGROUPS
select CGROUP_SCHED
select FAIR_GROUP_SCHED