This change swapped out mod_node_page_state for lruvec_stat_add_folio. But, these two APIs are not interchangeable: the lruvec version also increments memcg stats, in addition to "global" pgdat stats.

So after this change, the "pagetables" memcg stat in memory.stat always yields "0", which is a userspace visible regression.

I tried to look for a refactor where we add a variant of lruvec_stat_mod_folio which takes a pgdat and a memcg instead of a folio, to try to adhere to the spirit of the original patch. But at the end of the day this just means we have to call folio_memcg(ptdesc_folio(ptdesc)) anyway, which doesn't really accomplish much.

This regression is visible in master as well as 6.18 stable, so CC stable too.

Fixes f0c92726e89f ("ptdesc: remove references to folios from __pagetable_ctor() and pagetable_dtor()")

Cc [email protected]

Signed-off-by Axel Rasmussen <[email protected]>