Function vm_thread_swapout

freebsd/vm/vm_swapout.c:527–550

* Allow a thread's kernel stack to be paged out. */

 * Allow a thread's kernel stack to be paged out.
 */
static void
vm_thread_swapout(struct thread *td)
{
	vm_page_t m;
	vm_offset_t kaddr;
	vm_pindex_t pindex;
	int i, pages;

	cpu_thread_swapout(td);
	kaddr = td->td_kstack;
	pages = td->td_kstack_pages;
	pindex = atop(kaddr - VM_MIN_KERNEL_ADDRESS);
	pmap_qremove(kaddr, pages);
	VM_OBJECT_WLOCK(kstack_object);
	for (i = 0; i < pages; i++) {
		m = vm_page_lookup(kstack_object, pindex + i);
		if (m == NULL)
			panic("vm_thread_swapout: kstack already missing?");
		vm_page_dirty(m);
		vm_page_xunbusy_unchecked(m);
		vm_page_unwire(m, PQ_LAUNDRY);
	}
	VM_OBJECT_WUNLOCK(kstack_object);
}

/*
 * Bring the kernel stack for a specified thread back in.