Messages in this thread | | | Date | Thu, 7 Apr 2016 12:42:59 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCHSET RFC cgroup/for-4.6] cgroup, sched: implement resource group and PRIO_RGRP |
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On Thu, Apr 07, 2016 at 05:28:24AM -0400, Johannes Weiner wrote: > Hm? The root group can always contain tasks. It's not the only thing > the root is exempt from, it can't control any resources either:
it does in fact control resouces; the hierarchy directly affects the proportional distribution of time.
> sched_group_set_shares(): > > /* > * We can't change the weight of the root cgroup. > */ > if (!tg->se[0]) > return -EINVAL;
The root has, per definition, no siblings, so setting a weight is entirely pointless.
> tg_set_cfs_bandwidth(): > > if (tg == &root_task_group) > return -EINVAL; >
We have had patches to implement this, but have so far held off because they add a bunch of cycles to some really hot paths and we'd rather not do that. Its not impossible, or unthinkable to do this otherwise.
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