Function swapout

freebsd/vm/vm_swapout.c:896–948

}

static int
swapout(struct proc *p)
{
	struct thread *td;

	PROC_LOCK_ASSERT(p, MA_OWNED);

	/*
	 * The states of this process and its threads may have changed
	 * by now.  Assuming that there is only one pageout daemon thread,
	 * this process should still be in memory.
	 */
	KASSERT((p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) ==
	    P_INMEM, ("swapout: lost a swapout race?"));

	/*
	 * Remember the resident count.
	 */
	p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);

	/*
	 * Check and mark all threads before we proceed.
	 */
	p->p_flag &= ~P_INMEM;
	p->p_flag |= P_SWAPPINGOUT;
	FOREACH_THREAD_IN_PROC(p, td) {
		thread_lock(td);
		if (!thread_safetoswapout(td)) {
			thread_unlock(td);
			swapclear(p);
			return (EBUSY);
		}
		td->td_flags &= ~TDF_INMEM;
		TD_SET_SWAPPED(td);
		thread_unlock(td);
	}
	td = FIRST_THREAD_IN_PROC(p);
	++td->td_ru.ru_nswap;
	PROC_UNLOCK(p);

	/*
	 * This list is stable because all threads are now prevented from
	 * running.  The list is only modified in the context of a running
	 * thread in this process.
	 */
	FOREACH_THREAD_IN_PROC(p, td)
		vm_thread_swapout(td);

	PROC_LOCK(p);
	p->p_flag &= ~P_SWAPPINGOUT;
	p->p_swtick = ticks;
	return (0);
}