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

[Daisuke Nishimura]

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

> Fixed one here.
> ==
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> 
> 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@xxxxxxxxxxxxxx>

Acked-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
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