From: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
To: Ying Han <yinghan@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
Michal Hocko <mhocko@suse.cz>,
Johannes Weiner <hannes@cmpxchg.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Glauber Costa <glommer@parallels.com>, Tejun Heo <tj@kernel.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC][PATCH 5/9 v2] move charges to root at rmdir if use_hierarchy is unset
Date: Sat, 28 Apr 2012 09:01:23 +0900 [thread overview]
Message-ID: <CABEgKgpCyWhe1KMgcF7ob0myzcCypNbw5SebhVpSX_Xaz7yOBw@mail.gmail.com> (raw)
In-Reply-To: <CALWz4ixHGCqfWh1U+JyiJWTkGmCDtXQy1vbHRjrHaU_pOgGuBw@mail.gmail.com>
On Sat, Apr 28, 2012 at 4:12 AM, Ying Han <yinghan@google.com> wrote:
> On Thu, Apr 26, 2012 at 10:58 PM, KAMEZAWA Hiroyuki
> <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>> Now, at removal of cgroup, ->pre_destroy() is called and move charges
>> to the parent cgroup. A major reason of -EBUSY returned by ->pre_destroy()
>> is that the 'moving' hits parent's resource limitation. It happens only
>> when use_hierarchy=0. This was a mistake of original design.(it's me...)
>
> Nice patch, i can see how broken it is now with use_hierarchy=0...
>
> nitpick on the documentation below:
>
>>
>> Considering use_hierarchy=0, all cgroups are treated as flat. So, no one
>> cannot justify moving charges to parent...parent and children are in
>> flat configuration, not hierarchical.
>>
>> This patch modifes to move charges to root cgroup at rmdir/force_empty
>> if use_hierarchy==0. This will much simplify rmdir() and reduce error
>> in ->pre_destroy.
>>
>> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>> ---
>> Documentation/cgroups/memory.txt | 12 ++++++----
>> mm/memcontrol.c | 39 +++++++++++++------------------------
>> 2 files changed, 21 insertions(+), 30 deletions(-)
>>
>> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
>> index 54c338d..82ce1ef 100644
>> --- a/Documentation/cgroups/memory.txt
>> +++ b/Documentation/cgroups/memory.txt
>> @@ -393,14 +393,14 @@ cgroup might have some charge associated with it, even though all
>> tasks have migrated away from it. (because we charge against pages, not
>> against tasks.)
>>
>> -Such charges are freed or moved to their parent. At moving, both of RSS
>> -and CACHES are moved to parent.
>> -rmdir() may return -EBUSY if freeing/moving fails. See 5.1 also.
>> +Such charges are freed or moved to their parent if use_hierarchy=1.
>> +if use_hierarchy=0, the charges will be moved to root cgroup.
>
> It is more clear that we move the stats to root (if use_hierarchy==0)
> or parent (if use_hierarchy==1), and no change on the charge except
> uncharging from the child.
>
Seems nicer. I'll use your text in next ver.
Thanks,
-Kame
next prev parent reply other threads:[~2012-04-28 0:01 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-27 5:45 [RFC][PATCH 0/7 v2] memcg: prevent failure in pre_destroy() KAMEZAWA Hiroyuki
2012-04-27 5:49 ` [RFC][PATCH 1/7 v2] temporal compile-fix in linux-next KAMEZAWA Hiroyuki
2012-04-30 8:47 ` Aneesh Kumar K.V
2012-04-27 5:51 ` [RFC][PATCH 2/7 v2] memcg: fix error code in hugetlb_force_memcg_empty() KAMEZAWA Hiroyuki
2012-04-30 8:49 ` Aneesh Kumar K.V
2012-04-27 5:53 ` [RFC][PATCH 3/7 v2] res_counter: add res_counter_uncharge_until() KAMEZAWA Hiroyuki
2012-04-27 18:18 ` Tejun Heo
2012-04-27 23:51 ` Hiroyuki Kamezawa
[not found] ` <4F9AD28C.60508@parallels.com>
2012-04-27 23:51 ` Hiroyuki Kamezawa
2012-04-27 5:54 ` [RFC][PATCH 4/7 v2] memcg: use res_counter_uncharge_until in move_parent KAMEZAWA Hiroyuki
2012-04-27 18:20 ` Tejun Heo
2012-04-27 23:59 ` Hiroyuki Kamezawa
[not found] ` <4F9AD455.9030306@parallels.com>
2012-04-27 18:26 ` Ying Han
2012-04-27 23:58 ` Hiroyuki Kamezawa
2012-04-30 9:00 ` Aneesh Kumar K.V
2012-04-27 5:58 ` [RFC][PATCH 5/9 v2] move charges to root at rmdir if use_hierarchy is unset KAMEZAWA Hiroyuki
2012-04-27 19:12 ` Ying Han
2012-04-28 0:01 ` Hiroyuki Kamezawa [this message]
2012-04-30 9:07 ` Aneesh Kumar K.V
2012-04-27 6:00 ` [RFC][PATCH 6/9 v2] memcg: don't uncharge in mem_cgroup_move_account KAMEZAWA Hiroyuki
2012-04-27 6:02 ` [RFC][PATCH 7/9 v2] cgroup: avoid attaching task to a cgroup under rmdir() KAMEZAWA Hiroyuki
2012-04-27 10:39 ` Frederic Weisbecker
2012-04-28 0:06 ` Hiroyuki Kamezawa
2012-04-27 20:31 ` Tejun Heo
2012-04-27 20:33 ` Tejun Heo
2012-04-27 6:04 ` [RFC][PATCH 8/9 v2] cgroup: avoid creating new cgroup under a cgroup being destroyed KAMEZAWA Hiroyuki
2012-04-27 20:40 ` Tejun Heo
2012-04-27 20:41 ` Tejun Heo
2012-04-28 0:20 ` Hiroyuki Kamezawa
2012-04-28 2:00 ` Tejun Heo
2012-04-28 9:31 ` Hiroyuki Kamezawa
2012-04-28 21:31 ` Tejun Heo
2012-04-27 6:06 ` [RFC][PATCH 9/9 v2] memcg: never return error at pre_destroy() KAMEZAWA Hiroyuki
2012-04-27 21:28 ` Ying Han
2012-04-28 0:25 ` Hiroyuki Kamezawa
2012-04-30 17:02 ` Ying Han
2012-05-01 22:28 ` Suleiman Souhlal
2012-05-02 3:34 ` Hiroyuki Kamezawa
2012-04-27 18:16 ` [RFC][PATCH 0/7 v2] memcg: prevent failure in pre_destroy() Tejun Heo
2012-04-27 23:48 ` Hiroyuki Kamezawa
2012-04-28 16:13 ` Michal Hocko
2012-04-29 6:03 ` Michal Hocko
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