Understanding of kernel preemption and understanding of kernel preemption

Understanding of kernel preemption and understanding of kernel preemption

Whether the kernel can be preemptible is optional during kernel Compilation

After reading the book "Understanding the Linux kernel in depth", the author thinks it is difficult to preempt the next definition of the kernel. I also don't want to force the next definition. It's always a newbie. Let's talk about the kernel preemption phenomenon, understanding the kernel preemption mechanism through symptom

Kernel preemption: processes running in kernel state. It may be replaced by another process during running.

The above phenomenon is to allow kernel preemption, but it cannot be said that kernel preemption is the above phenomenon. We all know that when the interrupt processing program is executed, cannot be snatched by other processes to the cpu owned by the interrupt handler. This is an exception.

To sum up, kernel preemption is not allowed in the following cases when kernel preemption is allowed:

For details about scheduling after kernel preemption counters change, see