[Devel] Re: [PATCH 0/7] memcg kernel memory tracking

[Glauber Costa]

On 02/22/2012 11:08 AM, Pekka Enberg wrote:
> Hi Glauber,
>
> On Tue, Feb 21, 2012 at 1:34 PM, Glauber Costa<glommer at parallels.com>  wrote:
>> This is a first structured approach to tracking general kernel
>> memory within the memory controller. Please tell me what you think.
>
> I like it! I only skimmed through the SLUB changes but they seemed
> reasonable enough. What kind of performance hit are we taking when
> memcg configuration option is enabled but the feature is disabled?
>
>                          Pekka
Thanks Pekka.

Well, I didn't took any numbers, because I don't consider the whole work 
any close to final form, but I wanted people to comment anyway.

In particular, I intend to use the same trick I used for tcp sock 
buffers here for this case - (static_branch()), so the performance hit 
should come from two pointers in the kmem_cache structure - and I 
believe it is possible to remove one of them.

I can definitely measure when I implement that, but I think it is 
reasonable to expect not that much of a hit.