[Devel] [PATCH -mm 1/4] sl[au]b: do not charge large allocations to memcg

[Vladimir Davydov]

On 03/28/2014 12:43 AM, Michal Hocko wrote:
> On Thu 27-03-14 11:37:11, Vladimir Davydov wrote:
> [...]
>> In fact, do we actually need to charge every random kmem allocation? I
>> guess not. For instance, filesystems often allocate data shared among
>> all the FS users. It's wrong to charge such allocations to a particular
>> memcg, IMO. That said the next step is going to be adding a per kmem
>> cache flag specifying if allocations from this cache should be charged
>> so that accounting will work only for those caches that are marked so
>> explicitly.
> 
> How do you select which caches to track?

I though we should pick some objects that are definitely used by most
processes, e.g. mm_struct, task_struct, inodes, dentries, as a first
step, and then add some new objects to the set upon requests.

Now, after Greg's explanation, I admit the idea is rather unjustified,
because charging all objects by default and providing a way to
explicitly exclude some caches from accounting requires much less
efforts and changes to the code.

Thanks.