Messages in this thread | | | Date | Thu, 24 May 2018 16:36:14 +0200 | From | Juri Lelli <> | Subject | Re: [PATCH v8 3/6] cpuset: Add cpuset.sched.load_balance flag to v2 |
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On 17/05/18 16:55, Waiman Long wrote:
[...]
> + A parent cgroup cannot distribute all its CPUs to child > + scheduling domain cgroups unless its load balancing flag is > + turned off. > + > + cpuset.sched.load_balance > + A read-write single value file which exists on non-root > + cpuset-enabled cgroups. It is a binary value flag that accepts > + either "0" (off) or a non-zero value (on). This flag is set > + by the parent and is not delegatable. > + > + When it is on, tasks within this cpuset will be load-balanced > + by the kernel scheduler. Tasks will be moved from CPUs with > + high load to other CPUs within the same cpuset with less load > + periodically. > + > + When it is off, there will be no load balancing among CPUs on > + this cgroup. Tasks will stay in the CPUs they are running on > + and will not be moved to other CPUs. > + > + The initial value of this flag is "1". This flag is then > + inherited by child cgroups with cpuset enabled. Its state > + can only be changed on a scheduling domain cgroup with no > + cpuset-enabled children.
[...]
> + /* > + * On default hierachy, a load balance flag change is only allowed > + * in a scheduling domain with no child cpuset. > + */ > + if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && balance_flag_changed && > + (!is_sched_domain(cs) || css_has_online_children(&cs->css))) { > + err = -EINVAL; > + goto out; > + }
The rule is actually
- no child cpuset - and it must be a scheduling domain
Right?
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