On 09/18/2011 04:05 PM, Kirill A. Shutemov wrote:

On Sun, Sep 18, 2011 at 12:39:12AM -0300, Glauber Costa wrote:

quoted

quoted

No kernel memory accounting for root cgroup, right?

Not sure. Maybe kernel memory accounting is useful even for root cgroup.
Same as normal memory accounting... what we want to avoid is kernel
memory limits. OTOH, if we are not limiting it anyway, accounting it is
just useless overhead... Even the statistics can then be gathered
through all
the proc files that show slab usage, I guess?

It's better to leave root cgroup without accounting. At least for now.
We can add it later if needed.

Fair.

quoted

quoted

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@@ -3979,6 +3999,10 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
   		else
   			val = res_counter_read_u64(&mem->memsw, name);
   		break;
+	case _KMEM:
+		val = res_counter_read_u64(&mem->kmem, name);
+		break;
+

Always zero in root cgroup?

Yes, if we're not accounting, it should be zero. WARN_ON, maybe?

-ENOSYS?

I'd personally prefer WARN_ON. It is good symmetry from userspace PoV to 
always be able to get a value out of it. Also, it something goes wrong 
and it is not zero for some reason, this will help us find it.

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