From 2bdbc5bc16c338a43c9ac7ef93c1a60a8b17ee7d Mon Sep 17 00:00:00 2001 From: Qiang Huang Date: Wed, 11 May 2016 14:07:31 +0800 Subject: Documentation/memcg: update kmem limit doc as codes behavior The restriction of kmem setting is not there anymore because the accounting is enabled by default even in the cgroup v1 - see b313aeee2509 ("mm: memcontrol: enable kmem accounting for all cgroups in the legacy hierarchy"). Update docs accordingly. Signed-off-by: Qiang Huang Acked-by: Michal Hocko Signed-off-by: Jonathan Corbet diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt index ff71e16..b14abf2 100644 --- a/Documentation/cgroup-v1/memory.txt +++ b/Documentation/cgroup-v1/memory.txt @@ -280,17 +280,9 @@ 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 accounting is enabled for all memory cgroups by default. But +it can be disabled system-wide by passing cgroup.memory=nokmem to the kernel +at boot time. In this case, kernel memory will not be accounted at all. 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 -- cgit v0.10.2