> Il giorno 10 set 2019, alle ore 18:08, Tejun Heo <tj@xxxxxxxxxx> ha scritto: > > Hello, Michal. > > On Tue, Sep 10, 2019 at 02:55:14PM +0200, Michal Koutný wrote: >> This adds the generic io.weight attribute. How will this compose with >> the weight from IO schedulers? (AFAIK, only BFQ allows proportional >> control as of now. +CC Paolo.) > > The two being enabled at the same time doesn't make sense, so we can > just switch over to bfq when bfq is selected as the iosched. I asked > what Paolo wanted to do in terms of interface a couple times now but > didn't get an answer and he posted a patch which makes the two > controllers conflict, so.... Paolo, so it looks like you want to > rename all bfq files to drop the bfq prefix, right? Yep, mainly because ... this is the solution you voted and you yourself proposed [1] :) [1] https://patchwork.kernel.org/patch/10988261/ > I can implement > the switching if so. > That would be perfect. Thanks, Paolo >> I see this attributes are effectively per-cgroup per-device. Apparently, >> one device should have only one weight across hierarchy. Would it make >> sense to have io.bfq.weight and io.cost.weight with disjunctive devices? > > It never makes sense to have both enabled, so I don't think that > interface makes sense. > >>> + .name = "cost.qos", >>> + .flags = CFTYPE_ONLY_ON_ROOT, >>> [...] >>> + .name = "cost.model", >>> + .flags = CFTYPE_ONLY_ON_ROOT, >> I'm concerned that these aren't true cgroup attributes. The root cgroup >> would act as container for global configuration options. Wouldn't these >> values better fit as (configurable) attributes of the respective >> devices? > > Initially, I put them under block device sysfs but it was too clumsy > with different config file formats and all. I think it's better to > have global controller configs at the root cgroup. > >> Secondly, how is CFTYPE_ONLY_ON_ROOT supposed to be presented in cgroup >> namespaces? > > Not at all. These are system-wide configs. cgroup namespaces > shouldn't have anything which aren't in non-root cgroups. > > Thanks. > > -- > tejun
