Re: [PATCH v5 14/14] Add documentation about the kmem controller

From: Michal Hocko
Date: Tue Oct 16 2012 - 08:23:18 EST

On Tue 16-10-12 14:16:51, Glauber Costa wrote:
> Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
> CC: Frederic Weisbecker <fweisbec@xxxxxxxxxx>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Michal Hocko <mhocko@xxxxxxx>
> CC: Christoph Lameter <cl@xxxxxxxxx>
> CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxx>
> CC: Suleiman Souhlal <suleiman@xxxxxxxxxx>
> CC: Tejun Heo <tj@xxxxxxxxxx>

Acked-by: Michal Hocko <mhocko@xxxxxxx

Just a nit..
> ---
> Documentation/cgroups/memory.txt | 58 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 57 insertions(+), 1 deletion(-)
> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
> index c07f7b4..dd15be8 100644
> --- a/Documentation/cgroups/memory.txt
> +++ b/Documentation/cgroups/memory.txt
> @@ -268,20 +273,65 @@ 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. When use_hierarchy == 1 and a group is accounted, its children will
> +automatically be accounted regardless of their limit value.
> +
> +After a controller 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.
> +

Michal Hocko
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