On Tue, Sep 10, 2019 at 01:54:48PM +0200, Michal Hocko wrote: > On Fri 06-09-19 08:45:39, Tejun Heo wrote: > > Hello, Daniel. > > > > On Fri, Sep 06, 2019 at 05:34:16PM +0200, Daniel Vetter wrote: > > > > Hmm... what'd be the fundamental difference from slab or socket memory > > > > which are handled through memcg? Is system memory used by GPUs have > > > > further global restrictions in addition to the amount of physical > > > > memory used? > > > > > > Sometimes, but that would be specific resources (kinda like vram), > > > e.g. CMA regions used by a gpu. But probably not something you'll run > > > in a datacenter and want cgroups for ... > > > > > > I guess we could try to integrate with the memcg group controller. One > > > trouble is that aside from i915 most gpu drivers do not really have a > > > full shrinker, so not sure how that would all integrate. > > > > So, while it'd great to have shrinkers in the longer term, it's not a > > strict requirement to be accounted in memcg. It already accounts a > > lot of memory which isn't reclaimable (a lot of slabs and socket > > buffer). > > Yeah, having a shrinker is preferred but the memory should better be > reclaimable in some form. If not by any other means then at least bound > to a user process context so that it goes away with a task being killed > by the OOM killer. If that is not the case then we cannot really charge > it because then the memcg controller is of no use. We can tolerate it to > some degree if the amount of memory charged like that is negligible to > the overall size. But from the discussion it seems that these buffers > are really large. I think we can just make "must have a shrinker" as a requirement for system memory cgroup thing for gpu buffers. There's mild locking inversion fun to be had when typing one, but I think the problem is well-understood enough that this isn't a huge hurdle to climb over. And should give admins an easier to mange system, since it works more like what they know already. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
