OpenVZ Forum: Devel » [PATCH v3 00/16] slab accounting for memcg

Home » Mailing lists » Devel » [PATCH v3 00/16] slab accounting for memcg

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches [message #48042 is a reply to message #47966]

Fri, 21 September 2012 09:28

JoonSoo Kim
Messages: 9
Registered: September 2012

Junior Member

Hi, Glauber.

>> 2012/9/18 Glauber Costa <glommer@parallels.com>:
>>> diff --git a/mm/slub.c b/mm/slub.c
>>> index 0b68d15..9d79216 100644
>>> --- a/mm/slub.c
>>> +++ b/mm/slub.c
>>> @@ -2602,6 +2602,7 @@ redo:
>>> } else
>>> __slab_free(s, page, x, addr);
>>>
>>> + kmem_cache_verify_dead(s);
>>> }
>>
>> As far as u know, I am not a expert and don't know anything about memcg.
>> IMHO, this implementation may hurt system performance in some case.
>>
>> In case of memcg is destoried, remained kmem_cache is marked "dead".
>> After it is marked,
>> every free operation to this "dead" kmem_cache call
>> kmem_cache_verify_dead() and finally call kmem_cache_shrink().
>
> As long as it is restricted to that cache, this is a non issue.
> dead caches are exactly what they name imply: dead.
>
> Means that we actively want them to go away, and just don't kill them
> right away because they have some inflight objects - which we expect not
> to be too much.

Hmm.. I don't think so.
We can destroy memcg whenever we want, is it right?
If it is right, there is many inflight objects when we destory memcg.
If there is so many inflight objects, performance of these processes
can be hurt too much.

>> And, I found one case that destroying memcg's kmem_cache don't works properly.
>> If we destroy memcg after all object is freed, current implementation
>> doesn't destroy kmem_cache.
>> kmem_cache_destroy_work_func() check "cachep->memcg_params.nr_pages == 0",
>> but in this case, it return false, because kmem_cache may have
>> cpu_slab, and cpu_partials_slabs.
>> As we already free all objects, kmem_cache_verify_dead() is not invoked forever.
>> I think that we need another kmem_cache_shrink() in
>> kmem_cache_destroy_work_func().
>
> I'll take a look here. What you describe makes sense, and can
> potentially happen. I tried to handle this case with care in
> destroy_all_caches, but I may have always made a mistake...
>
> Did you see this actively happening, or are you just assuming this can
> happen from your read of the code?

Just read of the code.

Thanks.

Report message to a moderator

[Message index]

		[PATCH v3 00/16] slab accounting for memcg By: Glauber Costa on Tue, 18 September 2012 14:11
		[PATCH v3 02/16] slub: use free_page instead of put_page for freeing kmalloc allocation By: Glauber Costa on Tue, 18 September 2012 14:11
		[PATCH v3 01/16] slab/slub: struct memcg_params By: Glauber Costa on Tue, 18 September 2012 14:11
		[PATCH v3 03/16] slab: Ignore the cflgs bit in cache creation By: Glauber Costa on Tue, 18 September 2012 14:11
		Re: [PATCH v3 03/16] slab: Ignore the cflgs bit in cache creation By: Christoph Lameter on Tue, 18 September 2012 15:20
		Re: [PATCH v3 03/16] slab: Ignore the cflgs bit in cache creation By: Tejun Heo on Fri, 21 September 2012 17:33
		[PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Christoph Lameter on Tue, 18 September 2012 15:28
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Glauber Costa on Wed, 19 September 2012 07:42
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Christoph Lameter on Wed, 19 September 2012 14:14
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Pekka Enberg on Fri, 21 September 2012 09:33
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Glauber Costa on Fri, 21 September 2012 09:30
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Pekka Enberg on Fri, 21 September 2012 09:41
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Tejun Heo on Fri, 21 September 2012 20:07
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Pekka Enberg on Fri, 21 September 2012 20:14
		Re: [PATCH v3 09/16] sl[au]b: always get the cache from its page in kfree By: Tejun Heo on Fri, 21 September 2012 20:16
		[PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Tejun Heo on Fri, 21 September 2012 18:32
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Glauber Costa on Mon, 24 September 2012 08:46
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Tejun Heo on Mon, 24 September 2012 17:56
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Glauber Costa on Tue, 25 September 2012 13:57
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Christoph Lameter on Tue, 25 September 2012 16:28
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Tejun Heo on Fri, 21 September 2012 20:52
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Glauber Costa on Mon, 24 September 2012 08:17
		Re: [PATCH v3 06/16] memcg: infrastructure to match an allocation to the right cache By: Tejun Heo on Mon, 24 September 2012 17:58
		[PATCH v3 04/16] provide a common place for initcall processing in kmem_cache By: Glauber Costa on Tue, 18 September 2012 14:11
		Re: [PATCH v3 04/16] provide a common place for initcall processing in kmem_cache By: Christoph Lameter on Tue, 18 September 2012 15:22
		[PATCH v3 07/16] memcg: skip memcg kmem allocations in specified code regions By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 07/16] memcg: skip memcg kmem allocations in specified code regions By: Tejun Heo on Fri, 21 September 2012 19:59
		Re: [PATCH v3 07/16] memcg: skip memcg kmem allocations in specified code regions By: Glauber Costa on Mon, 24 September 2012 09:09
		Re: [PATCH v3 07/16] memcg: skip memcg kmem allocations in specified code regions By: Tejun Heo on Mon, 24 September 2012 17:47
		[PATCH v3 12/16] memcg/sl[au]b Track all the memcg children of a kmem_cache. By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 12/16] memcg/sl[au]b Track all the memcg children of a kmem_cache. By: Tejun Heo on Fri, 21 September 2012 20:31
		[PATCH v3 14/16] slub: slub-specific propagation changes. By: Glauber Costa on Tue, 18 September 2012 14:12
		[PATCH v3 16/16] Add documentation about the kmem controller By: Glauber Costa on Tue, 18 September 2012 14:12
		[PATCH v3 08/16] slab: allow enable_cpu_cache to use preset values for its tunables By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 08/16] slab: allow enable_cpu_cache to use preset values for its tunables By: Christoph Lameter on Tue, 18 September 2012 15:25
		Re: [PATCH v3 08/16] slab: allow enable_cpu_cache to use preset values for its tunables By: Glauber Costa on Wed, 19 September 2012 07:44
		Re: [PATCH v3 08/16] slab: allow enable_cpu_cache to use preset values for its tunables By: Pekka Enberg on Fri, 21 September 2012 09:29
		[PATCH v3 10/16] sl[au]b: Allocate objects from memcg cache By: Glauber Costa on Tue, 18 September 2012 14:12
		[PATCH v3 13/16] slab: slab-specific propagation changes. By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 13/16] slab: slab-specific propagation changes. By: Christoph Lameter on Tue, 18 September 2012 17:00
		Re: [PATCH v3 13/16] slab: slab-specific propagation changes. By: Glauber Costa on Wed, 19 September 2012 07:41
		[PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Glauber Costa on Tue, 18 September 2012 14:11
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Tejun Heo on Fri, 21 September 2012 18:14
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Glauber Costa on Mon, 24 September 2012 08:12
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: christoph on Mon, 24 September 2012 12:41
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Glauber Costa on Mon, 24 September 2012 12:41
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Christoph Lameter on Mon, 24 September 2012 13:42
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Glauber Costa on Mon, 24 September 2012 13:44
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Christoph Lameter on Mon, 24 September 2012 13:56
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Glauber Costa on Mon, 24 September 2012 13:57
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Pekka Enberg on Mon, 24 September 2012 15:38
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Glauber Costa on Mon, 24 September 2012 15:36
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Christoph Lameter on Mon, 24 September 2012 17:38
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Christoph Lameter on Mon, 24 September 2012 17:39
		Re: [PATCH v3 05/16] consider a memcg parameter in kmem_create_cache By: Michal Hocko on Tue, 02 October 2012 14:46
		[PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Christoph Lameter on Tue, 18 September 2012 17:02
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Glauber Costa on Wed, 19 September 2012 07:40
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Glauber Costa on Fri, 21 September 2012 08:40
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: JoonSoo Kim on Fri, 21 September 2012 09:28
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Glauber Costa on Fri, 21 September 2012 09:31
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Tejun Heo on Fri, 21 September 2012 20:40
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Glauber Costa on Mon, 24 September 2012 08:25
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: Tejun Heo on Mon, 24 September 2012 17:43
		Re: [PATCH v3 15/16] memcg/sl[au]b: shrink dead caches By: JoonSoo Kim on Fri, 21 September 2012 04:48
		[PATCH v3 11/16] memcg: destroy memcg caches By: Glauber Costa on Tue, 18 September 2012 14:12
		Re: [PATCH v3 11/16] memcg: destroy memcg caches By: Tejun Heo on Fri, 21 September 2012 20:22
		Re: [PATCH v3 00/16] slab accounting for memcg By: Pekka Enberg on Fri, 21 September 2012 09:40
		Re: [PATCH v3 00/16] slab accounting for memcg By: Glauber Costa on Fri, 21 September 2012 09:43
		Re: [PATCH v3 00/16] slab accounting for memcg By: Tejun Heo on Fri, 21 September 2012 20:46
		Re: [PATCH v3 00/16] slab accounting for memcg By: Tejun Heo on Fri, 21 September 2012 20:47
		Re: [PATCH v3 00/16] slab accounting for memcg By: Glauber Costa on Mon, 24 September 2012 08:15

Previous Topic:	[PATCH 0/5] nfs: few cleanup patches inspired by sparse
Next Topic:	[PATCH v3 04/13] kmem accounting basic infrastructure

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Thu Apr 03 05:30:39 GMT 2025

Total time taken to generate the page: 0.07132 seconds