A technical opinion on Linux kernel's withdrawal of kernel_FPU{begin,end} (2019)

Withdrawal of this pair of kernel calls was what made it impossible to continue in-kernel support of OpenZFS's cache decision algorithm, hurting OpenZFS performance on mainline Linux.

This opinion argues it was a plain technical decision that would have happened sooner or later, so no malice by the kernel team drove the decision. An alternative view is that the call could have been deprecated with a timetable of removal, allowing the OpenZFS team time to react to the new regime.