首先对于 Idle 是什么，我知之甚少，所以采用提出疑惑、回答问题的方式先进行行文，进行入门。
cpuidle_idle_callis a function in the Linux kernel that is responsible for putting the CPU into an idle state when there is no work to do. The function is part of the CPU idle subsystem, which is designed to reduce power consumption by putting the CPU into low-power states when it is not in use.
cpuidle_idle_callfunction is called, the CPU idle governor selects the most appropriate idle state based on the current system workload and the capabilities of the CPU. The CPU is then put into the selected idle state, which reduces its power consumption while still allowing it to quickly resume normal operation when needed.
cpuidle_idle_callfunction is called by the kernel scheduler when there is no work to do, and it is one of the key components of the Linux kernel's power management system. By efficiently managing CPU power consumption, the kernel can reduce energy usage and extend the battery life of mobile devices.