Hi, > > It's possible the algorithm of dm-ioband can be placed in the block layer > > if it is really a big problem. > > But I doubt it can control every control block I/O as we wish since > > the interface the cgroup supports is quite poor. > > Had a question regarding cgroup interface. I am assuming that in a system, > one will be using other controllers as well apart from IO-controller. > Other controllers will be using cgroup as a grouping mechanism. > Now coming up with additional grouping mechanism for only io-controller seems > little odd to me. It will make the job of higher level management software > harder. > > Looking at the dm-ioband grouping examples given in patches, I think cases > of grouping based in pid, pgrp, uid and kvm can be handled by creating right > cgroup and making sure applications are launched/moved into right cgroup by > user space tools. Grouping in pid, pgrp and uid is not the point, which I've been thinking can be replaced with cgroup once the implementation of bio-cgroup is done. I think problems of cgroup are that they can't support lots of storages and hotplug devices, it just handle them as if they were just one resource. I don't insist the interface of dm-ioband is the best. I just hope the cgroup infrastructure support this kind of resources. > I think keeping grouping mechanism in line with rest of the controllers > should help because a uniform grouping mechanism should make life simpler. > > I am not very sure about moving dm-ioband algorithm in block layer. Looks > like it will make life simpler at least in terms of configuration. Thanks, Hirokazu Takahashi. -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
