The ordering of lru_cache_add*, page_add_*_rmap and set_pte_at does
not matter (but update_mmu_cache must come after set_pte_at not before).
Even if the page table lock were not held across them (it is), I think
their ordering would not matter much (just benign races); though it's
always worth keeping in mind that once you've done the lru_cache_add,
that page is now visible to vmscan.c.
But I'm all in favour of you imposing consistency there (as part of
a wider patch? perhaps not; and do_swap_page does now look out of step).
It can sometimes help when inserting debug checks e.g. on page_mapcount.
I think you'll find the lru_cache_add_active_or_noreclaim could
actually be moved into page_add_new_rmap - I found that helpful when
working on eliminating the PageSwapCache flag (work now grown out of
date, I'm afraid), to know that the page was not publicly visible
until I did lru_cache_add_active at the end of page_add_new_rmap.
Hugh
--
