Re: [mm] [PATCH 1/4] Memory cgroup hierarchy documentation (v4)

[Li Zefan <lizf@cn.fujitsu.com>]

> +6.1 Enabling hierarchical accounting and reclaim
> +
> +The memory controller by default disables the hierarchy feature. Support
> +can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup
> +
> +# echo 1 > memory.use_hierarchy
> +
> +The feature can be disabled by
> +
> +# echo 0 > memory.use_hierarchy
> +
> +NOTE1: Enabling/disabling will fail if the cgroup already has other
> +cgroups created below it.
> +

It's better to also document that it will fail if it's parent's use_hierarchy
is already enabled.

> +NOTE2: This feature can be enabled/disabled per subtree.
> +
> +7. TODO
>  
>  1. Add support for accounting huge pages (as a separate controller)
>  2. Make per-cgroup scanner reclaim not-shared pages first
> _
>