pageflush
unsigned long pageflush;
++mp->pageflush;
mp->pagealloc, mp->pageflush);
setpgt4m_va(vaddr_t va, int *ptep, int pte, int pageflush, int ctx,
updatepte4m(va, ptep, 0xffffffff, pte, pageflush ? ctx : 0, cpuset);
if (__predict_true(pageflush))
error = pageflush(mp, cred, waitfor);