> At earlier review I remembered asking for a external data structure for this.
>
> It's also quite unobvious that a innocent looking Kconfig option with a
> single line Kconfig description has such a negative effect.
>
> This patch attempts to document these disadvantages at least so that users
> configuring their kernel can make a informed decision.
>
> Cc:
balbir@linux.vnet.ibm.com
>
> Signed-off-by: Andi Kleen <ak@suse.de>
>
> Index: linux/init/Kconfig
> ===================================================================
> --- linux.orig/init/Kconfig
> +++ linux/init/Kconfig
> @@ -394,6 +394,14 @@ config CGROUP_MEM_CONT
> Provides a memory controller that manages both page cache and
> RSS memory.
>
> + Note that setting this option increases fixed memory overhead
> + associated with each page of memory in the system by 4/8 bytes
> + and also increases cache misses because struct page on many 64bit
> + systems will not fit into a single cache line anymore.
> +
> + Only enable when you're ok with these trade offs and really
> + sure you need the memory controller.
> +
