Re: [PATCH v3 04/13] kmem accounting basic infrastructure

On Wed 26-09-12 18:33:10, Glauber Costa wrote:

On 09/26/2012 06:03 PM, Michal Hocko wrote:

quoted

On Tue 18-09-12 18:04:01, Glauber Costa wrote:

[...]

quoted

quoted

@@ -4961,6 +5015,12 @@ mem_cgroup_create(struct cgroup *cont)
 		int cpu;
 		enable_swap_cgroup();
 		parent = NULL;
+
+#ifdef CONFIG_MEMCG_KMEM
+		WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys,
+					   kmem_cgroup_files));
+#endif
+
 		if (mem_cgroup_soft_limit_tree_init())
 			goto free_out;
 		root_mem_cgroup = memcg;

@@ -4979,6 +5039,7 @@ mem_cgroup_create(struct cgroup *cont)
 	if (parent && parent->use_hierarchy) {
 		res_counter_init(&memcg->res, &parent->res);
 		res_counter_init(&memcg->memsw, &parent->memsw);
+		res_counter_init(&memcg->kmem, &parent->kmem);

Haven't we already discussed that a new memcg should inherit kmem_accounted
from its parent for use_hierarchy?
Say we have
root
|
A (kmem_accounted = 1, use_hierachy = 1)
 \
  B (kmem_accounted = 0)
   \
    C (kmem_accounted = 1)

B find's itself in an awkward situation becuase it doesn't want to
account u+k but it ends up doing so becuase C.

Ok, I haven't updated it here. But that should be taken care of in the
lifecycle patch.

I am not sure which patch you are thinking about but I would prefer to
have it here because it is safe wrt. races and it is more obvious as
well.

-- 
Michal Hocko
SUSE Labs