From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kamezawa Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>
Subject: Re: [PATCH v4 23/25] memcg: propagate kmem limiting information to
 children
Date: Mon, 18 Jun 2012 21:37:01 +0900
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To: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Pekka Enberg <penberg-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Cristoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>, David Rientjes <rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Suleiman Souhlal <suleiman-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Pekka Enberg <penberg-bbCR+/B0CizivPeTLB3BmA@public.gmane.org>, Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>

(2012/06/18 19:28), Glauber Costa wrote:
> The current memcg slab cache management fails to present satisfatory hierarchical
> behavior in the following scenario:
> 
> ->  /cgroups/memory/A/B/C
> 
> * kmem limit set at A
> * A and B empty taskwise
> * bash in C does find /
> 
> Because kmem_accounted is a boolean that was not set for C, no accounting
> would be done. This is, however, not what we expect.
> 

Hmm....do we need this new routines even while we have mem_cgroup_iter() ?

Doesn't this work ?

	struct mem_cgroup {
		.....
		bool kmem_accounted_this;
		atomic_t kmem_accounted;
		....
	}

at set limit

	....set_limit(memcg) {

		if (newly accounted) {
			mem_cgroup_iter() {
				atomic_inc(&iter->kmem_accounted)
			}
		} else {
			mem_cgroup_iter() {
				atomic_dec(&iter->kmem_accounted);
			}
	}


hm ? Then, you can see kmem is accounted or not by atomic_read(&memcg->kmem_accounted);

Thanks,
-Kame