Yield the current processor to another thread in your thread group, or accelerate that thread toward the processor its on.
int __sched yield_to(struct task_struct * p, bool preempt);
p
target task
preempt
whether task preemption is allowed or not
It's the caller's job to ensure that the target task struct can't go away on us before we can do any checks.
true (>0) if we indeed boosted the target task. false (0) if we failed to boost the target. -ESRCH if there's no task to yield to.