try_to_unmap
void try_to_unmap(struct folio *, enum ttu_flags flags);
try_to_unmap(folio, ttu_flags | TTU_IGNORE_MLOCK);
try_to_unmap(folio,
try_to_unmap(folio, ttu|TTU_RMAP_LOCKED);
try_to_unmap(folio, ttu);
try_to_unmap(folio, ttu_flags);
try_to_unmap(folio, flags);