Re: [PATCH v2 1/7] Basic kernel memory functionality for the MemoryController

[Glauber Costa]

On 09/18/2011 04:05 PM, Kirill A. Shutemov wrote:
> On Sun, Sep 18, 2011 at 12:39:12AM -0300, Glauber Costa wrote:
> > > 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.

> > > > @@ -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.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/