On Tue 18-08-20 11:59:10, Peter Zijlstra wrote: > On Tue, Aug 18, 2020 at 11:26:17AM +0200, Michal Hocko wrote: > > On Tue 18-08-20 11:14:53, Peter Zijlstra wrote: > > > On Mon, Aug 17, 2020 at 10:08:23AM -0400, Waiman Long wrote: > > > > Memory controller can be used to control and limit the amount of > > > > physical memory used by a task. When a limit is set in "memory.high" in > > > > a v2 non-root memory cgroup, the memory controller will try to reclaim > > > > memory if the limit has been exceeded. Normally, that will be enough > > > > to keep the physical memory consumption of tasks in the memory cgroup > > > > to be around or below the "memory.high" limit. > > > > > > > > Sometimes, memory reclaim may not be able to recover memory in a rate > > > > that can catch up to the physical memory allocation rate. In this case, > > > > the physical memory consumption will keep on increasing. > > > > > > Then slow down the allocator? That's what we do for dirty pages too, we > > > slow down the dirtier when we run against the limits. > > > > This is what we actually do. Have a look at mem_cgroup_handle_over_high. > > But then how can it run-away like Waiman suggested? As Chris mentioned in other reply. This functionality is quite new. > /me goes look... and finds MEMCG_MAX_HIGH_DELAY_JIFFIES. We can certainly tune a different backoff delays but I suspect this is not the problem here. > That's a fail... :-( -- Michal Hocko SUSE Labs
