多核Linux内核中的上下文切换

Question

Does Linux Kernel perform multiple context switches concurrently, if required in parallel on more than one cores of a multicore processor machine? Any reference?

Answer 1

Yeah, you're right. On SMP system, multiple context switches happen concurrently. Each core can do context switch independently. Of course, if needed, spinlock_* is needed to protect critical section.

Maybe you want to know when will one core decide to do context switch, there are several situations:

(1) Interrupts happen;

(2) Exceptions happen;

(3) User process system call;

(4) In kernel space(not interrupt/exception context), there are also codes which call schedule() to give up CPU;

(5) ...;