On 8/10/21 5:17 PM, Shakeel Butt wrote: > On Tue, Aug 10, 2021 at 12:24 PM Nico Pache <npache@xxxxxxxxxx> wrote: >> >> > [...] >>> >>> I'm wondering how you're getting anon scans with swappiness=0. If you >>> look at get_scan_count(), SCAN_FRACT with swappines=0 should always >>> result in ap = fraction[0] = 0, which never yields any anon scan >>> targets. So I'm thinking you're running into sc->file_is_tiny >>> situations, meaning remaining file pages alone are not enough to >>> restore watermarks anymore. Is that possible? >> >> Yes DEACTIVATE_ANON is enabling the file_is_tiny case in shrink_node(). That is what im trying to prevent in the swappiness=0 case. >> > > Can you please explain how DEACTIVATE_ANON is enabling the file_is_tiny case? You're right. Just did a second pass... I misinterpreted the assignment to file_is_tiny. This is not the case that is causing the issue. So back to the SCAN_FRACT case. From my testing the refaulting still seems to be causing the issue; however, to your point in earlier discussions, if swappiness=0 then the get_scan_count *should* be 0. So my patch does solve the issue by preventing the shrink_list from deactivating the anon, but it may be hiding some other issue that is the ultimate cause. Thanks for pointing that out! -- Nico
