[Devel] Re: [PATCH v4 23/25] memcg: propagate kmem limiting information to children

[Kamezawa Hiroyuki]

(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