On Tue 04-09-18 23:44:03, Andrea Arcangeli wrote: [...] > That kind of swapping may only pay off in the very long long term, > which is what khugepaged is for. khugepaged already takes care of the > long term, so we could later argue and think if khugepaged should > swapout or not in such condition, but I don't think there's much to > argue about the page fault. I agree that defrag==always doing a reclaim is not really good and benefits are questionable. If you remember this was the primary reason why the default has been changed. > > Thanks for your and Stefan's testing. I will wait for some more > > feedback. I will be offline next few days and if there are no major > > objections I will repost with both tested-bys early next week. > > I'm not so positive about 2 of the above tests if I understood the > test correctly. > > Those results are totally fine if you used the non default memory > policy, but with MPOL_DEFAULT and in turn no hard bind of the memory, > I'm afraid it'll be even be harder to reproduce when things will go > wrong again in those two cases. We can and should think about this much more but I would like to have this regression closed. So can we address GFP_THISNODE part first and build more complex solution on top? Is there any objection to my patch which does the similar thing to your patch v2 in a different location? -- Michal Hocko SUSE Labs
