On Mon, Sep 21, 2020 at 12:07:23PM -0700, Vijay Balakrishna wrote: > > > > I would recommend reposting the patch which adds heuristic for THP (if > > THP is enabled) into the hotplug path, arguing with the consistency and > > surprising results when adding memory decreases the value. > > I hope my reposted patch > ([v3 1/2] mm: khugepaged: recalculate min_free_kbytes after memory hotplug > as expected by khugepaged) > change log is ok: > > When memory is hotplug added or removed the min_free_kbytes must be > recalculated based on what is expected by khugepaged. Currently > after hotplug, min_free_kbytes will be set to a lower default and higher > default set when THP enabled is lost. This change restores min_free_kbytes > as expected for THP consumers. Any scenario when hotremove would result in changing min_free_kbytes? > > Your initial > > problem is in sizing as mentioned in other email thread and you should > > be investigating more but this inconsistency might really come as a > > surprise. > > > > All that if Kirill is reconsidering his initial position of course. > > > > Kirill, can you comment or share your opinion? Looking again, never decreasing min_free_kbytes is the most reasonable policy. Sorry for the noise. But I would like to see a scenario when hotremov will end up changing min_free_kbytes. It's not obvious to me. -- Kirill A. Shutemov
