From: Vasily Averin <vvs@virtuozzo.com>
To: Vlastimil Babka <vbabka@suse.cz>, Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>,
Christoph Lameter <cl@linux.com>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Pekka Enberg <penberg@kernel.org>, Linux MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
kernel@openvz.org
Subject: Re: slabinfo shows incorrect active_objs ???
Date: Thu, 24 Feb 2022 16:16:57 +0300 [thread overview]
Message-ID: <d654825e-af18-342a-7c90-db42fb161f78@virtuozzo.com> (raw)
In-Reply-To: <324372c6-1d9e-cdc9-b5b3-157746da8445@suse.cz>
On 22.02.2022 19:32, Shakeel Butt wrote:
> If you are just interested in the stats, you can use SLAB for your experiments.
Unfortunately memcg_slabino.py does not support SLAB right now.
On 23.02.2022 20:31, Vlastimil Babka wrote:
> On 2/23/22 04:45, Hyeonggon Yoo wrote:
>> On Wed, Feb 23, 2022 at 01:32:36AM +0100, Vlastimil Babka wrote:
>>> Hm it would be easier just to disable merging when the precise counters are
>>> enabled. Assume it would be a config option (possibly boot-time option with
>>> static keys) anyway so those who don't need them can avoid the overhead.
>>
>> Is it possible to accurately account objects in SLUB? I think it's not
>> easy because a CPU can free objects to remote cpu's partial slabs using
>> cmpxchg_double()...
>
> AFAIU Roman's idea would be that each alloc/free would simply inc/dec an
> object counter that's disconnected from physical handling of particular sl*b
> implementation. It would provide exact count of objects from the perspective
> of slab users.
> I assume for reduced overhead the counters would be implemented in a percpu
> fashion as e.g. vmstats. Slabinfo gathering would thus have to e.g. sum up
> those percpu counters.
I like this idea too and I'm going to spend some time for its implementation.
Thank you,
Vasily Averin
next prev parent reply other threads:[~2022-02-24 13:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-22 9:22 Vasily Averin
2022-02-22 10:23 ` Hyeonggon Yoo
2022-02-22 12:10 ` Vasily Averin
2022-02-22 16:32 ` Shakeel Butt
2022-02-22 16:47 ` Roman Gushchin
2022-02-23 1:07 ` Vasily Averin
2022-02-22 20:59 ` Roman Gushchin
2022-02-22 23:08 ` Vlastimil Babka
2022-02-23 0:07 ` Roman Gushchin
2022-02-23 0:32 ` Vlastimil Babka
2022-02-23 3:45 ` Hyeonggon Yoo
2022-02-23 17:31 ` Vlastimil Babka
2022-02-23 18:15 ` Roman Gushchin
2022-02-24 13:16 ` Vasily Averin [this message]
2022-02-25 0:08 ` Roman Gushchin
2022-02-25 4:37 ` Vasily Averin
2022-02-28 6:17 ` Vasily Averin
2022-02-28 10:22 ` Hyeonggon Yoo
2022-02-28 10:28 ` Hyeonggon Yoo
2022-02-28 10:43 ` Hyeonggon Yoo
2022-02-28 12:09 ` Hyeonggon Yoo
2022-03-03 8:39 ` Christoph Lameter
2022-03-04 16:29 ` Vlastimil Babka
2022-02-22 11:10 ` Vlastimil Babka
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