On Fri, May 20, 2016 at 10:02:18AM +0200, Michal Hocko wrote: > On Fri 20-05-16 16:44:50, Minchan Kim wrote: > > > > > That being said khugepaged_max_ptes_none = HPAGE_PMD_NR/2 sounds like a > > > > > > > > max_ptes_none? > > > > > > Not sure I understand what you mean here. > > > > We are talking about max_ptes_swap and max_active_pages(i.e., pte_young) > > but suddenly you are saying max_ptes_none so I was curious it was just > > typo. > > Because the default for pte_none resp. zero pages collapsing into THP is > khugepaged_max_ptes_none and the current default means that a single > present page is sufficient. That is way too optimistic. So I consider > this to be a good start. I am not so sure about minimum young pages > because that would probably require yet another tunable and we have more > than enough of them. Anyway I guess we are getting off-topic here... Optimistic swapin collapsing 1. it could be too optimisitic to lose the gain due to evicting workingset 2. let's detect memory pressure 3. current allocstall magic is not a good idea. 4. let's change the design from optimistic to conservative 5. how we can be conservative 6. two things - detect hot pages and threshold of swap pte 7. threhsold of swap pte is already done so remained thing is detect hot page 8. how to detect hot page - let's use young bit 9. Now, we are conservatie so we will swap in when it's worth 10. let's remove allocstall magic I think it's not off-topic. Anyway, it's just my thought and don't have any real workload and objection. Feel free to ignore. > -- > Michal Hocko > SUSE Labs > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>