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From: Roman Gushchin <guro@fb.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Christopher Lameter <cl@linux.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>, <linux-mm@kvack.org>,
	<kernel-team@fb.com>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 04/19] mm: slub: implement SLUB version of obj_to_index()
Date: Wed, 20 May 2020 13:57:45 -0700	[thread overview]
Message-ID: <20200520205745.GB278395@carbon.dhcp.thefacebook.com> (raw)
In-Reply-To: <88972cc2-2120-4257-ae8d-141e014c54e4@suse.cz>

On Wed, May 20, 2020 at 11:51:51AM +0200, Vlastimil Babka wrote:
> On 5/13/20 2:57 AM, Roman Gushchin wrote:
> > 
> > Btw, I'm trying to build up a prototype with an embedded memcg pointer,
> > but it seems to be way more tricky than I thought. It requires changes to
> > shrinkers (as they rely on getting the memcg pointer by an arbitrary
> > kernel address, not necessarily aligned to the head of slab allocation),
> > figuring out cache merging, adding SLAB support, natural alignment of
> > kmallocs etc.
> 
> Is the natural alignment of kmallocs a problem right now? As kmalloc()
> allocations are AFAIK not kmemcg-accounted? Or does your implementation add
> memcg awareness to everything, even if non-__GFP_ACCOUNT allocations just get a
> root memcg pointer?

There is at least a dozen of accounted kmallocs as now, please search for kmalloc
with GFP_KERNEL_ACCOUNT.

Natural alignment is not an issue with the proposed implementation, but it becomes
a problem as soon as we try to embed the memcg pointer into the object
(as Christopher is suggesting). I'm actually not opposing his suggestion, just
want to settle down the memcg part first, and then discuss the best way
to store the memcg metadata information. As I shown, the required changes to switch
between different ways of storing the data are minimal and do not affect
the rest of the patchset.

Thanks!

  reply	other threads:[~2020-05-20 20:58 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-22 20:46 [PATCH v3 00/19] The new cgroup slab memory controller Roman Gushchin
2020-04-22 20:46 ` [PATCH v3 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
2020-05-07 20:33   ` Johannes Weiner
2020-05-20 10:49   ` Vlastimil Babka
2020-04-22 20:46 ` [PATCH v3 02/19] mm: memcg: prepare for byte-sized vmstat items Roman Gushchin
2020-05-07 20:34   ` Johannes Weiner
2020-05-20 11:31   ` Vlastimil Babka
2020-05-20 11:36     ` Vlastimil Babka
2020-04-22 20:46 ` [PATCH v3 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin
2020-05-07 20:41   ` Johannes Weiner
2020-05-20 12:25   ` Vlastimil Babka
2020-05-20 19:26     ` Roman Gushchin
2020-05-21  9:57       ` Vlastimil Babka
2020-05-21 21:14         ` Roman Gushchin
2020-04-22 20:46 ` [PATCH v3 04/19] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
2020-04-22 23:52   ` Christopher Lameter
2020-04-23  0:05     ` Roman Gushchin
2020-04-25  2:10       ` Christopher Lameter
2020-04-25  2:46         ` Roman Gushchin
2020-04-27 16:21           ` Christopher Lameter
2020-04-27 16:46             ` Roman Gushchin
2020-04-28 17:06               ` Roman Gushchin
2020-04-28 17:45               ` Johannes Weiner
2020-04-30 16:29               ` Christopher Lameter
2020-04-30 17:15                 ` Roman Gushchin
2020-05-02 23:54                   ` Christopher Lameter
2020-05-04 18:29                     ` Roman Gushchin
2020-05-08 21:35                       ` Christopher Lameter
2020-05-13  0:57                         ` Roman Gushchin
2020-05-15 21:45                           ` Christopher Lameter
2020-05-15 22:12                             ` Roman Gushchin
2020-05-20  9:51                           ` Vlastimil Babka
2020-05-20 20:57                             ` Roman Gushchin [this message]
2020-05-15 20:02                         ` Roman Gushchin
2020-04-23 21:01     ` Roman Gushchin
2020-04-25  2:10       ` Christopher Lameter
2020-05-20 13:51   ` Vlastimil Babka
2020-05-20 21:00     ` Roman Gushchin
2020-05-21 11:01       ` Vlastimil Babka
2020-05-21 21:06         ` Roman Gushchin
2020-04-22 20:46 ` [PATCH v3 05/19] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
2020-04-22 20:46 ` [PATCH v3 06/19] mm: memcg/slab: obj_cgroup API Roman Gushchin
2020-05-07 21:03   ` Johannes Weiner
2020-05-07 22:26     ` Roman Gushchin
2020-05-12 22:56       ` Johannes Weiner
2020-05-15 22:01         ` Roman Gushchin
2020-04-22 20:46 ` [PATCH v3 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Roman Gushchin
2020-04-23 20:20   ` Roman Gushchin
2020-05-22 18:27   ` Vlastimil Babka
2020-05-23  1:32     ` Roman Gushchin
2020-05-26 17:50     ` Roman Gushchin
2020-05-25 14:46   ` Vlastimil Babka
2020-04-22 20:46 ` [PATCH v3 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects Roman Gushchin
2020-05-25 15:07   ` Vlastimil Babka
2020-05-26 17:53     ` Roman Gushchin
2020-05-27 11:03       ` Vlastimil Babka
2020-04-22 20:46 ` [PATCH v3 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
2020-05-25 16:10   ` Vlastimil Babka
2020-05-26 18:04     ` Roman Gushchin
2020-04-22 20:46 ` [PATCH v3 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo Roman Gushchin
2020-05-07 21:05   ` Johannes Weiner
2020-04-22 20:47 ` [PATCH v3 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
2020-05-25 17:03   ` Vlastimil Babka
2020-04-22 20:47 ` [PATCH v3 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations Roman Gushchin
2020-05-26 10:12   ` Vlastimil Babka
2020-04-22 20:47 ` [PATCH v3 13/19] mm: memcg/slab: simplify memcg cache creation Roman Gushchin
2020-05-26 10:31   ` Vlastimil Babka
2020-04-22 20:47 ` [PATCH v3 14/19] mm: memcg/slab: deprecate memcg_kmem_get_cache() Roman Gushchin
2020-05-26 10:34   ` Vlastimil Babka
2020-04-22 20:47 ` [PATCH v3 15/19] mm: memcg/slab: deprecate slab_root_caches Roman Gushchin
2020-05-26 10:52   ` Vlastimil Babka
2020-05-26 18:50     ` Roman Gushchin
2020-04-22 20:47 ` [PATCH v3 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() Roman Gushchin
2020-05-26 11:31   ` Vlastimil Babka
2020-04-22 20:47 ` [PATCH v3 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
2020-05-26 14:55   ` Vlastimil Babka
2020-05-27  8:35     ` Jesper Dangaard Brouer
2020-04-22 20:47 ` [PATCH v3 18/19] kselftests: cgroup: add kernel memory accounting tests Roman Gushchin
2020-05-26 15:24   ` Vlastimil Babka
2020-05-26 15:45     ` Roman Gushchin
2020-05-27 17:00       ` Vlastimil Babka
2020-05-27 20:45         ` Roman Gushchin
2020-04-22 20:47 ` [PATCH v3 19/19] tools/cgroup: add memcg_slabinfo.py tool Roman Gushchin
2020-05-05 15:59   ` Tejun Heo

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