cpuset: Track cpusets that use parent's effective_cpus
In the default hierarchy, a cpuset will use the parent's effective_cpus if none of the requested CPUs can be granted from the parent. That can be a problem if a parent is a partition root with children partition roots. Changes to a parent's effective_cpus list due to changes in a child partition root may not be properly reflected in a child cpuset that use parent's effective_cpus because the cpu_exclusive rule of a partition root will not guard against that. In order to avoid the mismatch, two new tracking variables are added to the cpuset structure to track if a cpuset uses parent's effective_cpus and the number of children cpusets that use its effective_cpus. So whenever cpumask changes are made to a parent, it will also check to see if it has other children cpusets that use its effective_cpus and call update_cpumasks_hier() if that is the case. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Tejun Heo <tj@kernel.org>
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