On Sat, Feb 01, 2025 at 10:29:23PM +0900, Hyeonggon Yoo wrote: > The Linux kernel supports hot-plugging CXL memory via dax/kmem functionality. > The hot-plugged memory allows either unmovable kernel allocations > (ZONE_NORMAL), or restricts them to movable allocations (ZONE_MOVABLE) > depending on the hot-plug policy. This all seems like a grand waste of time. Don't do that. Don't allow kernel allocations from CXL at all. Don't build systems that have vast quantities of CXL memory (or if you do, expose it as really fast swap, not as memory). All of the CXL topics I see this year are "It really hurts performance when ..." and my reaction is "Yes, I told you it would hurt and you did it anyway". Just stop doing it. CXL is this decade's Infiniband / ATM / (name your favourite misguided dead technology here). You can't stop other people from doing foolish things, but you don't have to join in. And we don't have to take stupid patches.
