From: Richard Palethorpe <rpalethorpe@suse.de>
To: ltp@lists.linux.it
Subject: [LTP] [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups from charging root
Date: Fri, 16 Oct 2020 11:41:43 +0100 [thread overview]
Message-ID: <87sgaesba0.fsf@suse.de> (raw)
In-Reply-To: <20201016094702.GA95052@blackbook>
Hello Michal,
Michal Koutn? <mkoutny@suse.com> writes:
> Hello.
>
> On Wed, Oct 14, 2020 at 08:07:49PM +0100, Richard Palethorpe <rpalethorpe@suse.com> wrote:
>> SLAB objects which outlive their memcg are moved to their parent
>> memcg where they may be uncharged. However if they are moved to the
>> root memcg, uncharging will result in negative page counter values as
>> root has no page counters.
> Why do you think those are reparented objects? If those are originally
> charged in a non-root cgroup, then the charge value should be propagated up the
> hierarchy, including root memcg, so if they're later uncharged in root
> after reparenting, it should still break even. (Or did I miss some stock
> imbalance?)
I traced it and can see they are reparented objects and that the root
groups counters are zero (or negative if I run madvise06 multiple times)
before a drain takes place. I'm guessing this is because the root group
has 'use_hierachy' set to false so that the childs page_counter parents
are set to NULL. However I will check, because I'm not sure about
either.
>
> (But the patch seems justifiable to me as objects (not)charged directly to
> root memcg may be incorrectly uncharged.)
>
> Thanks,
> Michal
--
Thank you,
Richard.
WARNING: multiple messages have this Message-ID (diff)
From: Richard Palethorpe <rpalethorpe@suse.de>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: Roman Gushchin <guro@fb.com>,
ltp@lists.linux.it, Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
Christoph Lameter <cl@linux.com>,
Michal Hocko <mhocko@kernel.org>, Tejun Heo <tj@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups from charging root
Date: Fri, 16 Oct 2020 11:41:43 +0100 [thread overview]
Message-ID: <87sgaesba0.fsf@suse.de> (raw)
In-Reply-To: <20201016094702.GA95052@blackbook>
Hello Michal,
Michal Koutný <mkoutny@suse.com> writes:
> Hello.
>
> On Wed, Oct 14, 2020 at 08:07:49PM +0100, Richard Palethorpe <rpalethorpe@suse.com> wrote:
>> SLAB objects which outlive their memcg are moved to their parent
>> memcg where they may be uncharged. However if they are moved to the
>> root memcg, uncharging will result in negative page counter values as
>> root has no page counters.
> Why do you think those are reparented objects? If those are originally
> charged in a non-root cgroup, then the charge value should be propagated up the
> hierarchy, including root memcg, so if they're later uncharged in root
> after reparenting, it should still break even. (Or did I miss some stock
> imbalance?)
I traced it and can see they are reparented objects and that the root
groups counters are zero (or negative if I run madvise06 multiple times)
before a drain takes place. I'm guessing this is because the root group
has 'use_hierachy' set to false so that the childs page_counter parents
are set to NULL. However I will check, because I'm not sure about
either.
>
> (But the patch seems justifiable to me as objects (not)charged directly to
> root memcg may be incorrectly uncharged.)
>
> Thanks,
> Michal
--
Thank you,
Richard.
next prev parent reply other threads:[~2020-10-16 10:41 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 19:07 [LTP] [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups from charging root Richard Palethorpe
2020-10-14 19:07 ` Richard Palethorpe
2020-10-14 20:08 ` [LTP] " Roman Gushchin
2020-10-14 20:08 ` Roman Gushchin
2020-10-16 5:40 ` [LTP] " Richard Palethorpe
2020-10-16 5:40 ` Richard Palethorpe
2020-10-16 6:32 ` [LTP] [PATCH v2] " Richard Palethorpe
2020-10-16 9:47 ` [LTP] [RFC PATCH] " Michal =?unknown-8bit?q?Koutn=C3=BD?=
2020-10-16 9:47 ` Michal Koutný
2020-10-16 10:41 ` Richard Palethorpe [this message]
2020-10-16 10:41 ` Richard Palethorpe
2020-10-16 15:05 ` [LTP] " Richard Palethorpe
2020-10-16 15:05 ` Richard Palethorpe
2020-10-16 17:26 ` [LTP] " Michal =?unknown-8bit?q?Koutn=C3=BD?=
2020-10-16 17:26 ` Michal Koutný
2020-10-16 14:53 ` [LTP] " Johannes Weiner
2020-10-16 14:53 ` Johannes Weiner
2020-10-16 17:02 ` [LTP] " Roman Gushchin
2020-10-16 17:02 ` Roman Gushchin
2020-10-16 17:15 ` [LTP] " Michal =?unknown-8bit?q?Koutn=C3=BD?=
2020-10-16 17:15 ` Michal Koutný
2020-10-19 8:45 ` [LTP] " Richard Palethorpe
2020-10-19 8:45 ` Richard Palethorpe
2020-10-19 9:58 ` [LTP] [PATCH v3] " Richard Palethorpe
2020-10-19 9:58 ` Richard Palethorpe
2020-10-19 16:58 ` [LTP] " Shakeel Butt
2020-10-19 16:58 ` Shakeel Butt
2020-10-20 5:52 ` [LTP] " Richard Palethorpe
2020-10-20 5:52 ` Richard Palethorpe
2020-10-20 13:49 ` [LTP] " Richard Palethorpe
2020-10-20 13:49 ` Richard Palethorpe
2020-10-20 16:56 ` [LTP] " Shakeel Butt
2020-10-20 16:56 ` Shakeel Butt
2020-10-21 20:32 ` [LTP] " Roman Gushchin
2020-10-21 20:32 ` Roman Gushchin
2020-10-20 17:24 ` [LTP] " Michal =?unknown-8bit?q?Koutn=C3=BD?=
2020-10-20 17:24 ` Michal Koutný
2020-10-22 7:04 ` [LTP] " Richard Palethorpe
2020-10-22 7:04 ` Richard Palethorpe
2020-10-22 12:28 ` [LTP] [PATCH v4] " Richard Palethorpe
2020-10-22 12:28 ` Richard Palethorpe
2020-10-22 16:37 ` [LTP] " Shakeel Butt
2020-10-22 16:37 ` Shakeel Butt
2020-10-22 17:25 ` [LTP] " Roman Gushchin
2020-10-22 17:25 ` Roman Gushchin
2020-10-22 23:59 ` [LTP] " Shakeel Butt
2020-10-22 23:59 ` Shakeel Butt
2020-10-23 0:40 ` [LTP] " Roman Gushchin
2020-10-23 0:40 ` Roman Gushchin
2020-10-23 15:44 ` [LTP] " Johannes Weiner
2020-10-23 15:44 ` Johannes Weiner
2020-10-23 16:41 ` [LTP] " Shakeel Butt
2020-10-23 16:41 ` Shakeel Butt
2020-10-26 7:32 ` [LTP] " Richard Palethorpe
2020-10-26 7:32 ` Richard Palethorpe
2020-10-26 23:14 ` [LTP] " Roman Gushchin
2020-10-26 23:14 ` Roman Gushchin
2020-10-19 22:28 ` [LTP] [RFC PATCH] " Roman Gushchin
2020-10-19 22:28 ` Roman Gushchin
2020-10-20 6:04 ` [LTP] " Richard Palethorpe
2020-10-20 6:04 ` Richard Palethorpe
2020-10-20 12:02 ` [LTP] " Richard Palethorpe
2020-10-20 12:02 ` Richard Palethorpe
2020-10-20 14:48 ` [LTP] " Richard Palethorpe
2020-10-20 14:48 ` Richard Palethorpe
2020-10-20 16:27 ` [LTP] " Michal =?unknown-8bit?q?Koutn=C3=BD?=
2020-10-20 16:27 ` Michal Koutný
2020-10-20 17:07 ` [LTP] " Roman Gushchin
2020-10-20 17:07 ` Roman Gushchin
2020-10-20 18:18 ` [LTP] " Johannes Weiner
2020-10-20 18:18 ` Johannes Weiner
2020-10-21 19:33 ` [LTP] " Roman Gushchin
2020-10-21 19:33 ` Roman Gushchin
2020-10-23 16:30 ` [LTP] " Johannes Weiner
2020-10-23 16:30 ` Johannes Weiner
2020-11-10 1:27 ` [LTP] " Roman Gushchin
2020-11-10 1:27 ` Roman Gushchin
2020-11-10 15:11 ` [LTP] " Shakeel Butt
2020-11-10 15:11 ` Shakeel Butt
2020-11-10 19:13 ` [LTP] " Roman Gushchin
2020-11-10 19:13 ` Roman Gushchin
2020-11-20 17:46 ` [LTP] " Michal =?unknown-8bit?q?Koutn=C3=BD?=
2020-11-20 17:46 ` Michal Koutný
2020-11-03 13:22 ` [LTP] " Michal Hocko
2020-11-03 13:22 ` Michal Hocko
2020-11-03 21:30 ` [LTP] " Roman Gushchin
2020-11-03 21:30 ` Roman Gushchin
2020-10-20 16:55 ` [LTP] " Shakeel Butt
2020-10-20 16:55 ` Shakeel Butt
2020-10-20 17:17 ` [LTP] " Roman Gushchin
2020-10-20 17:17 ` Roman Gushchin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87sgaesba0.fsf@suse.de \
--to=rpalethorpe@suse.de \
--cc=ltp@lists.linux.it \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.