To initialize its "fair" scheduler Linux's bootup routine iterates over all CPU cores allocating several CPU-mask nodes while possibly (depending on build flags) registering a callback & initializing a list.

After that it registers an IRQ handler into a small-int-map then (if buildtime enabled) sets some stamps & allocates another CPU-mask node.

0.5/0.5 since my other thread went long... Tomorrow: Papyrix's vendored version of Expat & booting Linux's ext scheduler!