On Wed 15-08-12 13:33:55, Glauber Costa wrote: [...] > > This can > > be quite confusing. I am still not sure whether we should mix the two > > things together. If somebody wants to limit the kernel memory he has to > > touch the other limit anyway. Do you have a strong reason to mix the > > user and kernel counters? > > This is funny, because the first opposition I found to this work was > "Why would anyone want to limit it separately?" =p > > It seems that a quite common use case is to have a container with a > unified view of "memory" that it can use the way he likes, be it with > kernel memory, or user memory. I believe those people would be happy to > just silently account kernel memory to user memory, or at the most have > a switch to enable it. > > What gets clear from this back and forth, is that there are people > interested in both use cases. I am still not 100% sure myself. It is just clear that the reclaim would need some work in order to do accounting like this. > > My impression was that kernel allocation should simply fail while user > > allocations might reclaim as well. Why should we reclaim just because of > > the kernel allocation (which is unreclaimable from hard limit reclaim > > point of view)? > > That is not what the kernel does, in general. We assume that if he wants > that memory and we can serve it, we should. Also, not all kernel memory > is unreclaimable. We can shrink the slabs, for instance. Ying Han > claims she has patches for that already... Are those patches somewhere around? [...] > > This doesn't check for the hierachy so kmem_accounted might not be in > > sync with it's parents. mem_cgroup_create (below) needs to copy > > kmem_accounted down from the parent and the above needs to check if this > > is a similar dance like mem_cgroup_oom_control_write. > > > > I don't see why we have to. > > I believe in a A/B/C hierarchy, C should be perfectly able to set a > different limit than its parents. Note that this is not a boolean. Ohh, I wasn't clear enough. I am not against setting the _limit_ I just meant that the kmem_accounted should be consistent within the hierarchy. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>