On Tue, Apr 24, 2018 at 02:54:15PM +0100, Roman Gushchin wrote: > > On Mon, Apr 23, 2018 at 01:36:10PM +0100, Roman Gushchin wrote: > > > + memory.min > > > + A read-write single value file which exists on non-root > > > + cgroups. The default is "0". > > > + > > > + Hard memory protection. If the memory usage of a cgroup > > > + is within its effective min boundary, the cgroup's memory > > > + won't be reclaimed under any conditions. If there is no > > > + unprotected reclaimable memory available, OOM killer > > > + is invoked. > > > > What will happen if all tasks attached to a cgroup are killed by OOM, > > but its memory usage is still within memory.min? Will memory.min be > > ignored then? > > Not really. > > I don't think it's a big problem as long as a user isn't doing > something weird (e.g. moving processes with significant > amount of charged memory to other cgroups).
The user doesn't have to do anything weird for this to happen - just read a file. This will allocate and charge page cache pages that are not mapped to any process and hence cannot be freed by OOM killer. > > But what we can do here, is to ignore memory.min of empty cgroups > (patch below), it will resolve some edge cases like this. Makes sense to me. Thanks, Vladimir
