On Mon, 14 Feb 2022 16:49:21 -0500 Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > Once upon a time, all swapins counted toward memory pressure[1]. Then > Joonsoo introduced workingset detection for anonymous pages and we > gained the ability to distinguish hot from cold swapins[2][3]. But we > failed to update swap_readpage() accordingly, and now we account > partial memory pressure in the swapin path of cold memory. > > Not for all situations - which adds more inconsistency: paths using > the conventional submit_bio() and lock_page() route will not see much > pressure - unless storage itself is heavily congested and the bio > submissions stall. ZRAM and ZSWAP do most of the work directly from > swap_readpage() and will see all swapins reflected as pressure. > > Restore consistency by making all swapin stall accounting conditional > on the page actually being part of the workingset. Does this have any known runtime effects? If not, can we hazard a guess?
