From: Michal Hocko <mhocko@suse.cz>
To: Glauber Costa <glommer@parallels.com>
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Balbir Singh <bsingharora@gmail.com>
Subject: Re: [PATCH v3 2/6] memcg: root_cgroup cannot reach mem_cgroup_move_parent
Date: Mon, 29 Oct 2012 14:52:03 +0100 [thread overview]
Message-ID: <20121029135203.GA20757@dhcp22.suse.cz> (raw)
In-Reply-To: <508E8910.40203@parallels.com>
On Mon 29-10-12 17:48:00, Glauber Costa wrote:
> On 10/26/2012 03:37 PM, Michal Hocko wrote:
> > The root cgroup cannot be destroyed so we never hit it down the
> > mem_cgroup_pre_destroy path and mem_cgroup_force_empty_write shouldn't
> > even try to do anything if called for the root.
> >
> > This means that mem_cgroup_move_parent doesn't have to bother with the
> > root cgroup and it can assume it can always move charges upwards.
> >
> > Signed-off-by: Michal Hocko <mhocko@suse.cz>
> > Reviewed-by: Tejun Heo <tj@kernel.org>
>
> I think it would be safer to have this folded in the last patch, to
> avoid a weird intermediate state (specially for force_empty).
force_empty excludes root cgroup explicitly so there is no way to fail
here. I have kept VM_BUG_ON for future reference but it also can go away
completely.
> Being a single statement, it doesn't confuse review so much.
>
> However, this is also pretty much just a nitpick, do as you prefer.
>
> Reviewed-by: Glauber Costa <glommer@parallels.com>
>
--
Michal Hocko
SUSE Labs
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2012-10-29 13:52 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 11:37 memcg/cgroup: do not fail fail on pre_destroy callbacks Michal Hocko
2012-10-26 11:37 ` [PATCH v3 1/6] memcg: split mem_cgroup_force_empty into reclaiming and reparenting parts Michal Hocko
2012-10-29 13:45 ` Glauber Costa
2012-10-31 16:29 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 2/6] memcg: root_cgroup cannot reach mem_cgroup_move_parent Michal Hocko
2012-10-29 13:48 ` Glauber Costa
2012-10-29 13:52 ` Michal Hocko [this message]
2012-10-31 16:31 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Michal Hocko
2012-10-29 13:58 ` Glauber Costa
2012-10-29 14:15 ` Michal Hocko
2012-10-29 15:09 ` Glauber Costa
2012-10-29 22:00 ` Andrew Morton
2012-10-30 10:35 ` Michal Hocko
2012-10-31 21:30 ` Andrew Morton
2012-11-13 21:10 ` Johannes Weiner
2012-11-14 13:59 ` Michal Hocko
2012-11-14 18:33 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 4/6] cgroups: forbid pre_destroy callback to fail Michal Hocko
2012-10-29 14:04 ` Glauber Costa
2012-10-29 14:06 ` Glauber Costa
2012-10-29 14:17 ` Michal Hocko
2012-11-13 21:13 ` Johannes Weiner
2012-10-26 11:37 ` [PATCH v3 5/6] memcg: make mem_cgroup_reparent_charges non failing Michal Hocko
2012-10-29 14:07 ` Glauber Costa
2012-10-26 11:37 ` [PATCH v3 6/6] hugetlb: do not fail in hugetlb_cgroup_pre_destroy Michal Hocko
2012-10-29 14:08 ` Glauber Costa
2012-10-29 23:26 ` memcg/cgroup: do not fail fail on pre_destroy callbacks Tejun Heo
2012-10-30 23:37 ` Michal Hocko
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=20121029135203.GA20757@dhcp22.suse.cz \
--to=mhocko@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=bsingharora@gmail.com \
--cc=cgroups@vger.kernel.org \
--cc=glommer@parallels.com \
--cc=hannes@cmpxchg.org \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lizefan@huawei.com \
--cc=tj@kernel.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).