On Thu, Nov 10, 2016 at 11:17:03AM +0800, Xishi Qiu wrote: > On 2016/11/9 19:58, Mel Gorman wrote: > > > On Tue, Nov 08, 2016 at 12:43:17PM +0800, Xishi Qiu wrote: > >> On mem-hotplug system, there is a problem, please see the following case. > >> > >> memtester xxG, the memory will be alloced on a movable node. And after numa > >> balancing, the memory may be migrated to the other node, it may be a > >> unmovable > >> node. This will reduce the free memory of the unmovable node, and may be > >> oom > >> later. > >> > > > > How would it OOM later? It's movable memmory that is moving via > > automatic NUMA balancing so at the very least it can be reclaimed. If > > the memory is mlocked or unable to migrate then it's irrelevant if > > automatic balancing put it there. > > > > memtester will mlock the memory, so we can not reclaim, then maybe oom, right? > So let the manager set some numa policies to prevent the above case, right? >
Deal with it using policies. -- Mel Gorman SUSE Labs
