On 08/12/2023 11:24, David Hildenbrand wrote: > On 05.12.23 14:49, Ryan Roberts wrote: >> On 05/12/2023 13:39, David Hildenbrand wrote: >>> On 05.12.23 14:31, Ryan Roberts wrote: >>>> On 05/12/2023 09:56, David Hildenbrand wrote: >>>>>>> >>>>>>> Ryan has series where we would make use of folio_remove_rmap_ptes() [1] >>>>>>> -- he carries his own batching variant right now -- and >>>>>>> folio_try_dup_anon_rmap_ptes()/folio_dup_file_rmap_ptes() [2]. >>>>>> >>>>>> Note that the contpte series at [2] has a new patch in v3 (patch 2), which >>>>>> could >>>>>> benefit from folio_remove_rmap_ptes() or equivalent. My plan was to revive >>>>>> [1] >>>>>> on top of [2] once it is merged. >>>>>> >>>>>>> >>>>>>> There is some overlap with both series (and some other work, like >>>>>>> multi-size THP [3]), so that will need some coordination, and likely a >>>>>>> stepwise inclusion. >>>>>> >>>>>> Selfishly, I'd really like to get my stuff merged as soon as there is no >>>>>> technical reason not to. I'd prefer not to add this as a dependency if we can >>>>>> help it. >>>>> >>>>> It's easy to rework either series on top of each other. The mTHP series has >>>>> highest priority, >>>>> no question, that will go in first. >>>> >>>> Music to my ears! It would be great to either get a reviewed-by or feedback on >>>> why not, for the key 2 patches in that series (3 & 4) and also your opinion on >>>> whether we need to wait for compaction to land (see cover letter). It would be >>>> great to get this into linux-next ASAP IMHO. >>> >>> On it :) >>> >>>> >>>>> >>>>> Regarding the contpte, I think it needs more work. Especially, as raised, >>>>> to not >>>>> degrade >>>>> order-0 performance. Maybe we won't make the next merge window (and you >>>>> already >>>>> predicated >>>>> that in some cover letter :P ). Let's see. >>>> >>>> Yeah that's ok. I'll do the work to fix the order-0 perf. And also do the same >>>> for patch 2 in that series - would also be really helpful if you had a >>>> chance to >>>> look at patch 2 - its new for v3. >>> >>> I only skimmed over it, but it seems to go into the direction we'll need. >>> Keeping order-0 performance unharmed should have highest priority. Hopefully my >>> microbenchmarks are helpful. >> >> Yes absolutely - are you able to share them?? >> >>> >>>> >>>>> >>>>> But again, the conflicts are all trivial, so I'll happily rebase on top of >>>>> whatever is >>>>> in mm-unstable. Or move the relevant rework to the front so you can just carry >>>>> them/base on them. (the batched variants for dup do make the contpte code much >>>>> easier) >>>> >>>> So perhaps we should aim for mTHP, then this, then contpte last, benefiting >>>> from >>>> the batching. >>> >>> Yeah. And again, I don't care too much if I have to rebase on top of your work >>> if this here takes longer. It's all a fairly trivial conversion. >>> >>>>> >>>>> [...] >>>>> >>>>>>> >>>>>>> >>>>>>> New (extended) hugetlb interface that operate on entire folio: >>>>>>> * hugetlb_add_new_anon_rmap() -> Already existed >>>>>>> * hugetlb_add_anon_rmap() -> Already existed >>>>>>> * hugetlb_try_dup_anon_rmap() >>>>>>> * hugetlb_try_share_anon_rmap() >>>>>>> * hugetlb_add_file_rmap() >>>>>>> * hugetlb_remove_rmap() >>>>>>> >>>>>>> New "ordinary" interface for small folios / THP:: >>>>>>> * folio_add_new_anon_rmap() -> Already existed >>>>>>> * folio_add_anon_rmap_[pte|ptes|pmd]() >>>>>>> * folio_try_dup_anon_rmap_[pte|ptes|pmd]() >>>>>>> * folio_try_share_anon_rmap_[pte|pmd]() >>>>>>> * folio_add_file_rmap_[pte|ptes|pmd]() >>>>>>> * folio_dup_file_rmap_[pte|ptes|pmd]() >>>>>>> * folio_remove_rmap_[pte|ptes|pmd]() >>>>>> >>>>>> I'm not sure if there are official guidelines, but personally if we are >>>>>> reworking the API, I'd take the opportunity to move "rmap" to the front of >>>>>> the >>>>>> name, rather than having it burried in the middle as it is for some of these: >>>>>> >>>>>> rmap_hugetlb_*() >>>>>> >>>>>> rmap_folio_*() >>>>> >>>>> No strong opinion. But we might want slightly different names then. For >>>>> example, >>>>> it's "bio_add_folio" and not "bio_folio_add": >>>>> >>>>> >>>>> rmap_add_new_anon_hugetlb() >>>>> rmap_add_anon_hugetlb() >>>>> ... >>>>> rmap_remove_hugetlb() >>>>> >>>>> >>>>> rmap_add_new_anon_folio() >>>>> rmap_add_anon_folio_[pte|ptes|pmd]() >>>>> ... >>>>> rmap_dup_file_folio_[pte|ptes|pmd]() >>>>> rmap_remove_folio_[pte|ptes|pmd]() >>>>> >>>>> Thoughts? >>>> >>>> Having now reviewed your series, I have a less strong opinion, perhaps it's >>>> actually best with your original names; "folio" is actually the subject after >>>> all; it's the thing being operated on. > > So far I sticked to the original names used in this RFC. I'm testing a new > series that is based on current mm/unstable (especially, mTHP) and contains all > changes discussed here. > > If I don't here anything else, I'll send that out as v1 on Monday. Get's my vote! > > Thanks! >
