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From: Bharata B Rao <bharata@linux.ibm.com>
To: Roman Gushchin <guro@fb.com>
Cc: "mhocko@kernel.org" <mhocko@kernel.org>,
	"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Kernel Team <Kernel-team@fb.com>,
	"shakeelb@google.com" <shakeelb@google.com>,
	"vdavydov.dev@gmail.com" <vdavydov.dev@gmail.com>,
	"longman@redhat.com" <longman@redhat.com>
Subject: Re: [PATCH 00/16] The new slab memory controller
Date: Mon, 13 Jan 2020 14:17:10 +0530	[thread overview]
Message-ID: <20200113084710.GC8458@in.ibm.com> (raw)
In-Reply-To: <20191210180516.GA23940@localhost.localdomain>

On Tue, Dec 10, 2019 at 06:05:20PM +0000, Roman Gushchin wrote:
> > 
> > With slab patches
> > # docker stats --no-stream
> > CONTAINER ID        NAME                CPU %               MEM USAGE / LIMIT   MEM %               NET I/O             BLOCK I/O           PIDS
> > 24bc99d94d91        sleek               0.00%               1MiB / 25MiB        4.00%               1.81kB / 0B         0B / 0B             0
> > 
> > Without slab patches
> > # docker stats --no-stream
> > CONTAINER ID        NAME                CPU %               MEM USAGE / LIMIT   MEM %               NET I/O             BLOCK I/O           PIDS
> > 52382f8aaa13        sleek               0.00%               8.688MiB / 25MiB    34.75%              1.53kB / 0B         0B / 0B             0
> > 
> > So that's an improvement of MEM USAGE from 8.688MiB to 1MiB. Note that this
> > docker container isn't doing anything useful and hence the numbers
> > aren't representative of any workload.
> 
> Cool, that's great!
> 
> Small containers is where the relative win is the biggest. Of course, it will
> decrease with the size of containers, but it's expected.
> 
> If you'll get any additional numbers, please, share them. It's really
> interesting, especially if you have larger-than-4k pages.

I run a couple of workloads contained within a memory cgroup and measured
memory.kmem.usage_in_bytes and memory.usage_in_bytes with and without
this patchset on PowerPC host. I see significant reduction in
memory.kmem.usage_in_bytes and some reduction in memory.usage_in_bytes.
Before posting the numbers, would like to get the following clarified:

In the original case, the memory cgroup is charged (including kmem charging)
when a new slab page is allocated. In your patch, the subpage charging is
done in slab_pre_alloc_hook routine. However in this case, I couldn't find
where exactly kmem counters are being charged/updated. Hence wanted to
make sure that the reduction in memory.kmem.usage_in_bytes that I am
seeing is indeed real and not because kmem accounting was missed out for
slab usage?

Also, I see all non-root allocations are coming from a single set of
kmem_caches. Guess <kmemcache_name>-memcg caches don't yet show up in
/proc/slabinfo and nor their stats is accumulated into /proc/slabinfo?

Regards,
Bharata.


  reply	other threads:[~2020-01-13  8:47 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05 21:45 [PATCH RFC 00/14] The new slab memory controller Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 01/14] mm: memcg: subpage charging API Roman Gushchin
2019-09-16 12:56   ` Johannes Weiner
2019-09-17  2:27     ` Roman Gushchin
2019-09-17  8:50       ` Johannes Weiner
2019-09-17 18:33         ` Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 02/14] mm: memcg: introduce mem_cgroup_ptr Roman Gushchin
2019-09-05 22:34   ` Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 03/14] mm: vmstat: use s32 for vm_node_stat_diff in struct per_cpu_nodestat Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 04/14] mm: vmstat: convert slab vmstat counter to bytes Roman Gushchin
2019-09-16 12:38   ` Johannes Weiner
2019-09-17  2:08     ` Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 05/14] mm: memcg/slab: allocate space for memcg ownership data for non-root slabs Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 06/14] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 07/14] mm: memcg/slab: save memcg ownership data for non-root slab objects Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 08/14] mm: memcg: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
2019-09-05 21:45 ` [PATCH RFC 09/14] mm: memcg: introduce __mod_lruvec_memcg_state() Roman Gushchin
2019-09-05 22:37 ` [PATCH RFC 02/14] mm: memcg: introduce mem_cgroup_ptr Roman Gushchin
2019-09-17 19:48 ` [PATCH RFC 00/14] The new slab memory controller Waiman Long
2019-09-17 21:24   ` Roman Gushchin
2019-09-19 13:39 ` Suleiman Souhlal
2019-09-19 16:22   ` Roman Gushchin
2019-09-19 21:10     ` Suleiman Souhlal
2019-09-19 21:40       ` Roman Gushchin
2019-10-01 15:12 ` Michal Koutný
2019-10-02  2:09   ` Roman Gushchin
2019-10-02 13:00     ` Suleiman Souhlal
2019-10-03 10:47       ` Michal Koutný
2019-10-03 15:52         ` Roman Gushchin
2019-12-09  9:17 ` [PATCH 00/16] " Bharata B Rao
2019-12-09 11:56   ` Bharata B Rao
2019-12-09 18:04     ` Roman Gushchin
2019-12-10  6:23       ` Bharata B Rao
2019-12-10 18:05         ` Roman Gushchin
2020-01-13  8:47           ` Bharata B Rao [this message]
2020-01-13 15:31             ` Roman Gushchin
2019-10-18  0:28 Roman Gushchin
2019-10-18 17:03 ` Waiman Long
2019-10-18 17:12   ` Roman Gushchin
2019-10-22 13:22 ` Michal Hocko
2019-10-22 13:28   ` Michal Hocko
2019-10-22 15:48     ` Roman Gushchin
2019-10-22 13:31 ` Michal Hocko
2019-10-22 15:59   ` Roman Gushchin

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