Date: Wed, 11 Jun 2008 16:24:23 -0700
From: Randy Dunlap <randy.dunlap@oracle.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
       LKML <linux-kernel@vger.kernel.org>,
       "balbir@linux.vnet.ibm.com" <balbir@linux.vnet.ibm.com>,
       "menage@google.com" <menage@google.com>,
       "xemul@openvz.org" <xemul@openvz.org>,
       "yamamoto@valinux.co.jp" <yamamoto@valinux.co.jp>
Subject: Re: [RFC][PATCH 2/2] memcg: hardwall hierarhcy for memcg
Message-Id: <20080611162423.3ba183b4.randy.dunlap@oracle.com>
In-Reply-To: <20080604140329.8db1b67e.kamezawa.hiroyu@jp.fujitsu.com>
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	<20080604140329.8db1b67e.kamezawa.hiroyu@jp.fujitsu.com>
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On Wed, 4 Jun 2008 14:03:29 +0900 KAMEZAWA Hiroyuki wrote:

> ---
>  Documentation/controllers/memory.txt |   27 +++++-
>  mm/memcontrol.c                      |  156 ++++++++++++++++++++++++++++++++++-
>  2 files changed, 178 insertions(+), 5 deletions(-)
> 

> Index: temp-2.6.26-rc2-mm1/Documentation/controllers/memory.txt
> ===================================================================
> --- temp-2.6.26-rc2-mm1.orig/Documentation/controllers/memory.txt
> +++ temp-2.6.26-rc2-mm1/Documentation/controllers/memory.txt
> @@ -237,12 +237,37 @@ cgroup might have some charge associated
>  tasks have migrated away from it. Such charges are automatically dropped at
>  rmdir() if there are no tasks.
>  
> -5. TODO
> +5. Hierarchy Model
> +  the kernel supports following kinds of hierarchy models.

     The kernel supports the following kinds ....

> +  (your middle-ware may support others based on this.)

     (Your
> +
> +  5-a. Independent Hierarchy
> +  There are no relationship between any cgroups, even among a parent and

           is

> +  children. This is the default mode. To use this hierarchy, write 0
> +  to root cgroup's memory.hierarchy_model
> +  echo 0 > .../memory.hierarchy_model.
> +
> +  5-b. Hardwall Hierarchy.
> +  The resource has to be moved from the parent to the child before use it.

                                                                      using it.

> +  When a child's limit is set to 'val', val of the resource is moved from
> +  the parent to the child. the parent's usage += val.

                              The parent's usage is incremented by val.
(if that's what you mean)

> +  The amount of children's usage is reported by the file
> +
> +  - memory.assigned_to_child
> +
> +  This policy doesn't provide sophisticated automatic resource balancing in
> +  the kernel. But this is very good for strict resource isolation. Users

         kernel, but this ...

> +  can get high predictability of behavior of applications if this is used
> +  under proper environments.
> +
> +
> +6. TODO
>  
>  1. Add support for accounting huge pages (as a separate controller)
>  2. Make per-cgroup scanner reclaim not-shared pages first
>  3. Teach controller to account for shared-pages
>  4. Start reclamation when the limit is lowered
> +   (this is already done in Hardwall Hierarchy)
>  5. Start reclamation in the background when the limit is
>     not yet hit but the usage is getting closer
> --

---
~Randy
'"Daemon' is an old piece of jargon from the UNIX operating system,
where it referred to a piece of low-level utility software, a
fundamental part of the operating system."
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