(2012/06/18 21:43), Glauber Costa wrote:

On 06/18/2012 04:37 PM, Kamezawa Hiroyuki wrote:

quoted

(2012/06/18 19:28), Glauber Costa wrote:

quoted

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);

Accounted by itself / parent is still useful, and I see no reason to use
an atomic + bool if we can use a pair of bits.

As for the routine, I guess mem_cgroup_iter will work... It does a lot
more than I need, but for the sake of using what's already in there, I
can switch to it with no problems.

Hmm. please start from reusing existing routines.
If it's not enough, some enhancement for generic cgroup  will be welcomed
rather than completely new one only for memcg.

Thanks,
-Kame