Re: New LXC HOW-TO

[Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>]

Dwight Schauer wrote:
> I'm trying to get the needed LXC kernel config options into the default Arch
> Linux kernel package.
> http://bugs.archlinux.org/task/16715
>
> There is a concern about any potential drawbacks in enabling these options,
> especially for those that don't use Linux containers.
>
> Is anyone aware of any negative impact (apart from size maybe) of having
> these features being enabled? Especially for those not using these features?
>
> On Sat, Oct 17, 2009 at 7:32 PM, Dwight Schauer <dschauer-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>
>   
>> I just made it and it is somewhat archlinux specific, but others might find
>> it useful.
>>
>> http://lxc.teegra.net/
>>
>> --
>> Dwight
>>
>>
>>
>>
>>     
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>
>   
In general the cgroup adds a small overhead at fork/exit when a subsystem make use of the cgroup_callbacks, for example the freezer. But that can be considered as negligeable.

CONFIG_GROUP_SCHED=y
CONFIG_FAIR_GROUP_SCHED=y
CONFIG_RT_GROUP_SCHED=y
CONFIG_CGROUP_SCHED=y
CONFIG_CGROUPS=y
CONFIG_CGROUP_NS=y
CONFIG_CGROUP_FREEZER=y

This one does not add any overhead.

CONFIG_CGROUP_DEVICE=y

For these ones, I don't know.

CONFIG_CPUSETS=y
CONFIG_PROC_PID_CPUSET=y

AFAIR these following options add some overhead especially the memory resource controller.

CONFIG_CGROUP_CPUACCT=y
CONFIG_RESOURCE_COUNTERS=y
CONFIG_CGROUP_MEM_RES_CTLR=y
CONFIG_CGROUP_MEM_RES_CTLR_SWAP=y
CONFIG_MM_OWNER=y


The overhead and footprint of the following options are neligeable

CONFIG_NAMESPACES=y
CONFIG_UTS_NS=y
CONFIG_IPC_NS=y
CONFIG_USER_NS=y
CONFIG_PID_NS=y
CONFIG_NET_NS=y
CONFIG_NET_CLS_CGROUP=y


This one, no overhead.
CONFIG_SECURITY_FILE_CAPABILITIES=y