On Aug 4, 2022, at 1:39 PM, Peter Xu <peterx@xxxxxxxxxx> wrote: > (1) Page Idle Tracking > > Before this series, idle tracking can cause false negative if an accessed > page got migrated, since after migration the young bit will get lost. > After this series, it'll be better in that after migration young bit will > be persisted, so it'll be able to be detected correctly by page idle > logic when walking the pgtable. > > However there's still nothing done when page idle reset was carried out > during migration procedure in progress, but that should be a separate > topic to be addressed (e.g. to teach rmap pgtable walk code to be able to > walk with both present ptes and migration ptes). IIUC, when a migration entry is set page_remove_rmap() is called by try_to_migrate_one(), so improving page-idle accuracy should be done in a different way.
