It's not so grim. "The origin of the CPU-count dependence is that NOVA divides PMEM into per-CPU allocation regions. We use the current CPU ID as a hint about

It's not so grim. "The origin of the CPU-count dependence is that NOVA divides PMEM into per-CPU allocation regions. We use the current CPU ID as a hint about which region to use and avoid contention on the locks that protect it. So moving from a smaller number of CPUs to a larger number of CPUs just means more contention for the locks. Moving from a larger number to a smaller number is no problem at all. So, our current plan is to set the CPU count very high (like 256) when the file system is created." - comment under the post by one of the designers of the fs