On 04/03/2012 06:17 AM, Tejun Heo wrote: > On Tue, Apr 03, 2012 at 06:03:03AM +0800, Tao Ma wrote: >> Currently weight is just used to calculate the time slice of different >> cfq group, right? So why can't it be used to indicate other weight? So >> say, if we are just want to use iops to indicate the difference between >> different cgroups(100 weight vs 200 weight), so one process will send >> 100 ios while the other will send 200 ios just for example. > > Because it's configuring stuff which is completely unrelated. Let's > say you added a new elevator w/ iops based proportional IO which > shares blkio.weight configuration with cfq but nothing else and in > turn your new thing would probably need some other config parameters > which don't make much sense for cfq, right? > > Now, let's say there's a system which has two hard drives and sda is > using cfq and sdb is using your new elevator and you're trying to > configure cgroup blkio limits. Now, you have blkio.weight which > applies to both elevators and other configurations which aren't and > from the looks of it there's no way to tell which configuration > controls what. > > It also makes the configuration implementation hairier. We'll need > callbacks from blkcg core layer to all policies to notify changes to > per-cgroup configuration and from there policies would have to decide > whether it has overriding per-cgroup-device configuration. It's not > even clear we even want per-cgroup configuration. blk-throttle only > has per-cgroup-device configuration after all. Fair enough. > > So, again, no. blkcg.weight isn't and won't be generic. > >> We will need a new iops_weight in your option to be exported? > > Yeah, just add config and stat files prefixed with the name of the new > blkcg policy. OK, I will add a new config file for it. Thanks Tao _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
