Merriam-Webster的解为：
preemption
n
1 the right of purchasing befor others; especially: one given by the government to the actual settler upon a tract of public land
2 the purchase of something under this right
3 a prior seizure or appropriation: a taking posssession before others
CONFIG_PREEMPT - This option reduces the latency of the kernel when reacting to real-time or interactive events by allowing a low priority process to be preempted even if it is in kernel mode executing a system call. Say Y here if you are building a kernel for a desktop, embedded or real-time system. Say N if you are unsure.
CONFIG_PREEMPT_BKL - This option reduces the latency of the kernel by making the big kernel lock （BKL）preemptible. Say Y here if you are building a kernel for a desktop system. Say N if you are unsure.