path: root/init
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authorLinus Torvalds <>2015-09-02 08:04:23 -0700
committerLinus Torvalds <>2015-09-02 08:04:23 -0700
commit8bdc69b764013a9b5ebeef7df8f314f1066c5d79 (patch)
tree335dcb29c9ba06142917121d551575d360eca63e /init
parent76ec51ef5edfe540bbc3c61b860f88deb8e6a37b (diff)
parent20f1f4b5ffb870631bf4a4e7c7ba10e3528ae6a6 (diff)
Merge branch 'for-4.3' of git://
Pull cgroup updates from Tejun Heo: - a new PIDs controller is added. It turns out that PIDs are actually an independent resource from kmem due to the limited PID space. - more core preparations for the v2 interface. Once cpu side interface is settled, it should be ready for lifting the devel mask. for-4.3-unified-base was temporarily branched so that other trees (block) can pull cgroup core changes that blkcg changes depend on. - a non-critical idr_preload usage bug fix. * 'for-4.3' of git:// cgroup: pids: fix invalid get/put usage cgroup: introduce cgroup_subsys->legacy_name cgroup: don't print subsystems for the default hierarchy cgroup: make cftype->private a unsigned long cgroup: export cgrp_dfl_root cgroup: define controller file conventions cgroup: fix idr_preload usage cgroup: add documentation for the PIDs controller cgroup: implement the PIDs subsystem cgroup: allow a cgroup subsystem to reject a fork
Diffstat (limited to 'init')
1 files changed, 16 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index ba1e6eaf4c36..bb9b4dd55889 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -947,6 +947,22 @@ config CGROUP_FREEZER
Provides a way to freeze and unfreeze all tasks in a
+ bool "PIDs cgroup subsystem"
+ help
+ Provides enforcement of process number limits in the scope of a
+ cgroup. Any attempt to fork more processes than is allowed in the
+ cgroup will fail. PIDs are fundamentally a global resource because it
+ is fairly trivial to reach PID exhaustion before you reach even a
+ conservative kmemcg limit. As a result, it is possible to grind a
+ system to halt without being limited by other cgroup policies. The
+ PIDs cgroup subsystem is designed to stop this from happening.
+ It should be noted that organisational operations (such as attaching
+ to a cgroup hierarchy will *not* be blocked by the PIDs subsystem),
+ since the PIDs limit only affects a process's ability to fork, not to
+ attach to a cgroup.
bool "Device controller for cgroups"