[$] Core scheduling lands in 5.14

The core scheduling feature has been underdiscussion for over three years. For those who need it, the waitis over at last; core scheduling was merged for the 5.14 kernel release.Now that this work has reached a (presumably) final form, a look at why this featuremakes sense and how it works is warranted. Core scheduling is not foreverybody, but it may prove to be quite useful for some user communities.