On Wed 16-11-16 10:44:58, Balbir Singh wrote: > In the absence of hotplug we use extra memory proportional to > (possible_nodes - online_nodes) * number_of_cgroups. PPC64 has a patch > to disable large consumption with large number of cgroups. This patch > adds hotplug support to memory cgroups and reverts the commit that > limited possible nodes to online nodes.
I didn't get to read patches yet (I am currently swamped by emails after longer vacation so bear with me) but this doesn't tell us _why_ we want this and how much we can actaully save. In general being dynamic is more complex and most systems tend to have possible_nodes close to online_nodes in my experience (well at least on most reasonable architectures). I would also appreciate some highlevel description of the implications. E.g. how to we synchronize with the hotplug operations when iterating node specific data structures. Thanks! -- Michal Hocko SUSE Labs