Documentation/cgroups/memory.txt: 2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
With the Kernel memory extension, the Memory Controller is able to limit the amount of kernel memory used by the system. Kernel memory is fundamentally different than user memory, since it can't be swapped out, which makes it possible to DoS the system by consuming too much of this precious resource. Kernel memory won't be accounted at all until limit on a group is set. This allows for existing setups to continue working without disruption. The limit cannot be set if the cgroup have children, or if there are already tasks in the cgroup. Attempting to set the limit under those conditions will return -EBUSY. When use_hierarchy == 1 and a group is accounted, its children will automatically be accounted regardless of their limit value. After a group is first limited, it will be kept being accounted until it is removed. The memory limitation itself, can of course be removed by writing -1 to memory.kmem.limit_in_bytes. In this case, kmem will be accounted, but not limited. Kernel memory limits are not imposed for the root cgroup. Usage for the root cgroup may or may not be accounted. The memory used is accumulated into memory.kmem.usage_in_bytes, or in a separate counter when it makes sense. (currently only for tcp). The main "kmem" counter is fed into the main counter, so kmem charges will also be visible from the user counter. Currently no soft limit is implemented for kernel memory. It is future work to trigger slab reclaim when those limits are reached. ** Also affects: linux (Ubuntu Trusty) Importance: Undecided Status: New ** Changed in: linux (Ubuntu Trusty) Status: New => In Progress ** Changed in: linux (Ubuntu Trusty) Assignee: (unassigned) => Tim Gardner (timg-tpi) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1309586 Title: enable CONFIG_MEMCG_KMEM To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1309586/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs