[Devel] Re: [PATCH v2 04/11] kmem accounting basic infrastructure

[Ying Han]

On Wed, Aug 15, 2012 at 8:11 AM, Glauber Costa <glommer at parallels.com> wrote:
> On 08/15/2012 06:47 PM, Christoph Lameter wrote:
>> On Wed, 15 Aug 2012, Michal Hocko wrote:
>>
>>>> That is not what the kernel does, in general. We assume that if he wants
>>>> that memory and we can serve it, we should. Also, not all kernel memory
>>>> is unreclaimable. We can shrink the slabs, for instance. Ying Han
>>>> claims she has patches for that already...
>>>
>>> Are those patches somewhere around?
>>
>> You can already shrink the reclaimable slabs (dentries / inodes) via
>> calls to the subsystem specific shrinkers. Did Ying Han do anything to
>> go beyond that?
>>
> That is not enough for us.
> We would like to make sure that the objects being discarded belong to
> the memcg which is under pressure. We don't need to be perfect here, and
> an occasional slip is totally fine. But if in general, shrinking from
> memcg A will mostly wipe out objects from memcg B, we harmed the system
> in return for nothing good.

Correct. For example, we have per-superblock shrinker today for vfs
caches. That is not enough since we need to isolate the dentry caches
per-memcg basis.

--Ying
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo at kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont at kvack.org"> email at kvack.org </a>