On 09/11/2012 04:38 PM, Li Zefan wrote: > On 2012/9/11 6:33, Tejun Heo wrote: >> (forgot cc'ing containers / cgroups mailing lists and used the old >> address for Li. Reposting. Sorry for the noise.) >> >> Currently, cgroup hierarchy support is a mess. cpu related subsystems >> behave correctly - configuration, accounting and control on a parent >> properly cover its children. blkio and freezer completely ignore >> hierarchy and treat all cgroups as if they're directly under the root >> cgroup. Others show yet different behaviors. >> >> These differing interpretations of cgroup hierarchy make using cgroup >> confusing and it impossible to co-mount controllers into the same >> hierarchy and obtain sane behavior. >> >> Eventually, we want full hierarchy support from all subsystems and >> probably a unified hierarchy. Users using separate hierarchies >> expecting completely different behaviors depending on the mounted >> subsystem is deterimental to making any progress on this front. >> >> This patch adds cgroup_subsys.broken_hierarchy and sets it to %true >> for controllers which are lacking in hierarchy support. The goal of >> this patch is two-fold. >> >> * Move users away from using hierarchy on currently non-hierarchical >> subsystems, so that implementing proper hierarchy support on those >> doesn't surprise them. >> >> * Keep track of which controllers are broken how and nudge the >> subsystems to implement proper hierarchy support. >> >> For now, start with a single warning message. We can whine louder >> later on. >> >> (I tried to document what's broken and how it should be fixed. If I >> got something wrong, please let me know.) >> > > So isn't cpuset broken too? child cpuset's cpu mask isn't necessary a subset > of the parent's if the cpu_exclusive flag is not set. > Li is right, cpu_exclusive is pretty much cpuset's version of memcg's use_hierarchy. the only problem is that it seem to be by design, unlike memcg's, which was there to bypass a performance problem to the best of my knowledge. Even then, we should maybe think about start enforcing that flag as well. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
