Re: [PATCH v2][memcg+dirtylimit] Fix overwriting global vm dirty limit setting by memcg (Re: [PATCH v3 00/11] memcg: per cgroup dirty page accounting

Daisuke Nishimura
2010-10-20T06:16:07Z

On Wed, 20 Oct 2010 14:02:55 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> Fixed one here.
> ==
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>
> Now, at calculating dirty limit, vm_dirty_param() is called.
> This function returns dirty-limit related parameters considering
> memory cgroup settings.
>
> Now, assume that vm_dirty_bytes=100M (global dirty limit) and
> memory cgroup has 1G of pages and 40 dirty_ratio, dirtyable memory is
> 500MB.
>
> In this case, global_dirty_limits will consider dirty_limt as
> 500 *0.4 = 200MB. This is bad...memory cgroup is not back door.
>
> This patch limits the return value of vm_dirty_param() considring
> global settings.
>
> Changelog:
> - fixed an argument "mem" int to u64
> - fixed to use global available memory to cap memcg's value.
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>