Function sched_setcpu

freebsd/kern/sched_ule.c:1201–1232

* Sets the thread lock and ts_cpu to match the requested cpu. Unlocks the * current lock and returns with the assigned queue locked. */

 * current lock and returns with the assigned queue locked.
 */
static inline struct tdq *
sched_setcpu(struct thread *td, int cpu, int flags)
{

	struct tdq *tdq;
	struct mtx *mtx;

	THREAD_LOCK_ASSERT(td, MA_OWNED);
	tdq = TDQ_CPU(cpu);
	td_get_sched(td)->ts_cpu = cpu;
	/*
	 * If the lock matches just return the queue.
	 */
	if (td->td_lock == TDQ_LOCKPTR(tdq)) {
		KASSERT((flags & SRQ_HOLD) == 0,
		    ("sched_setcpu: Invalid lock for SRQ_HOLD"));
		return (tdq);
	}

	/*
	 * The hard case, migration, we need to block the thread first to
	 * prevent order reversals with other cpus locks.
	 */
	spinlock_enter();
	mtx = thread_lock_block(td);
	if ((flags & SRQ_HOLD) == 0)
		mtx_unlock_spin(mtx);
	TDQ_LOCK(tdq);
	thread_lock_unblock(td, TDQ_LOCKPTR(tdq));
	spinlock_exit();
	return (tdq);
}

SCHED_STAT_DEFINE(pickcpu_intrbind, "Soft interrupt binding");
SCHED_STAT_DEFINE(pickcpu_idle_affinity, "Picked idle cpu based on affinity");