Tasklets Bottom half Scheduling

Question

Which scheduling algorithm is followed by Bottom half ? If one Bottom half is in execution and suppose another higher priority bottom half comes in that case what will be the behavior?

Please consider above case w.r.t to TASKLET

Answer 1

Each CPU has queues for scheduled (high-priority and normal) tasklets.

When a CPU is about to return to user space from an interrupt or from a system call, it checks for scheduled tasklets, and executes them. The same checks are done again after a tasklet has finished. (If there are too many scheduled tasklets, they are not all executed at once, but moved into a kernel thread, ksoftirqd; but the principle stays the same.)

Therefore, a tasklet will never interrupt another tasklet, but a high-priority tasklet will be executed before any scheduled 'normal' tasklets.