Re: [PATCH 08/10] memcg: Add CONFIG_CGROUP_MEM_RES_CTLR_KMEM_ACCT_ROOT.

On Tue, 28 Feb 2012 15:36:27 -0800
Suleiman Souhlal [off-list ref] wrote:

On Tue, Feb 28, 2012 at 5:34 AM, Glauber Costa [off-list ref] wrote:

quoted

On 02/27/2012 07:58 PM, Suleiman Souhlal wrote:

quoted

This config option dictates whether or not kernel memory in the
root cgroup should be accounted.

This may be useful in an environment where everything is supposed to be
in a cgroup and accounted for. Large amounts of kernel memory in the
root cgroup would indicate problems with memory isolation or accounting.

I don't like accounting this stuff to the root memory cgroup. This causes
overhead for everybody, including people who couldn't care less about memcg.

If it were up to me, we would simply not account it, and end of story.

However, if this is terribly important for you, I think you need to at
least make it possible to enable it at runtime, and default it to disabled.

Yes, that is why I made it a config option. If the config option is
disabled, that memory does not get accounted at all.

Making it configurable at runtime is not ideal, because we would
prefer slab memory that was allocated before cgroups are created to
still be counted toward root.

I never like to do accounting in root cgroup.
If you want to do this, add config option to account _all_ memory in the root.
Accounting only slab seems very dirty hack.

Thanks,
-Kame