Re: [RFC][PATCH 1/5] memcg : force_empty to do move account

[Paul Menage <menage@google.com>]

On Thu, Oct 30, 2008 at 6:52 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> This patch provides a function to move account information of a page between
> mem_cgroups and rewrite force_empty to make use of this.

One part of this that wasn't clear to me - if a cgroup has a lot of
unmapped pagecache sitting around but no tasks, and we try to rmdir
it, then all the pagecache gets moved to the parent too? Or just the
stray mapped pages?

> @@ -597,7 +709,7 @@ static int mem_cgroup_charge_common(stru
>        prefetchw(pc);
>
>        mem = memcg;
> -       ret = mem_cgroup_try_charge(mm, gfp_mask, &mem);
> +       ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);

Isn't this the same as the definition of mem_cgroup_try_charge()? So
you could leave it as-is?

Paul