On Wed 15-08-12 17:04:31, Glauber Costa wrote: > On 08/15/2012 05:02 PM, Michal Hocko wrote: > > On Wed 15-08-12 16:53:40, Glauber Costa wrote: > > [...] > >>>>> This doesn't check for the hierachy so kmem_accounted might not be in > >>>>> sync with it's parents. mem_cgroup_create (below) needs to copy > >>>>> kmem_accounted down from the parent and the above needs to check if this > >>>>> is a similar dance like mem_cgroup_oom_control_write. > >>>>> > >>>> > >>>> I don't see why we have to. > >>>> > >>>> I believe in a A/B/C hierarchy, C should be perfectly able to set a > >>>> different limit than its parents. Note that this is not a boolean. > >>> > >>> Ohh, I wasn't clear enough. I am not against setting the _limit_ I just > >>> meant that the kmem_accounted should be consistent within the hierarchy. > >>> > >> > >> If a parent of yours is accounted, you get accounted as well. This is > >> not the state in this patch, but gets added later. Isn't this enough ? > > > > But if the parent is not accounted, you can set the children to be > > accounted, right? Or maybe this is changed later in the series? I didn't > > get to the end yet. > > > > Yes, you can. Do you see any problem with that? Well, if a child contributes with the kmem charges upwards the hierachy then a parent can have kmem.usage > 0 with disabled accounting. I am not saying this is a no-go but it definitely is confusing and I do not see any good reason for it. I've considered it as an overlook rather than a deliberate design decision. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>