On Sun, Sep 19, 2021 at 11:25:09PM +0800, Yongmei Xie wrote: > Before commit #31d8fcac, VM didn't increase nonresident_age (AKA inactive age for > file pages) in shrink_page_list. When putback_inactive_pages was converged with > move_pages_to_lru, both shrink_active_list and shrink_page_list use the same > function to handle move pages to the appropriate lru under lru lock's protection. > > At those day, VM didn't increase nonresident_age for second chance promotion. > Commit #31d8fcac fix the problem. Definitely, we should account the activation > for second chance. But move_pages_to_lru is used in reactivation in active lru > as well for protecting code section. So I suggest to add another variable to > tell whether reactivation or not. This looks incorrect to me. We *should* count reactivations/rotations on the active list toward nonresident age. The nonresident age tracks the number of in-memory references in order to later calculate the (minimum) reuse distance of refaulting pages. If a page on the active list gets reactivated due to a reference, that reference contributes to the distance of yet-to-refault pages.
