On Tue, Nov 21, 2023 at 5:19 PM Nhat Pham <nphamcs@xxxxxxxxx> wrote: > > On Tue, Nov 21, 2023 at 11:09 AM Chris Li <chrisl@xxxxxxxxxx> wrote: > > > > On Tue, Nov 21, 2023 at 10:13 AM Nhat Pham <nphamcs@xxxxxxxxx> wrote: > > > > > > Hi Chris! > > > > > > Thanks for the patch. Would you mind if I spend some time staring > > > at the suggestion again and testing it some more? > > > > Of course, by all means. That is just the minimal version to be > > functional compatible with your zswap.writeback. > > > > I might consider a follow up patch to add "no_zswap" and "none" to > > convert the SSD only swapfile, which can't be expressed by > > zswap.writeback. > > That should cover all 4 combinations of zswap and swap files without > > creating a custom swap tiers list. > > > > "all": zswap + swapfile > > "zswap": zswap only > > "no_zswap": swapfile only. > > "none": no swap. > > > > All keyword names are open to suggestions. > > SGTM! There might be some functionality duplication between > memory.swap.tiers = no_zswap and memory.zswap.max = 0, but > otherwise this seems reasonable to me. Yes, there is some function duplication. However, there is some small difference that no_zswap will not enter zswap code at all. Vs memory.zswap.max will take a short trip into zswap code to find out Oops, not zswap for you. > > no_zswap sounds a bit awkward, but I can't come up with a better > name. Again, I am open to better suggestions. I have also considered "!zswap", "!" has special meaning in bash, so it will require quoting in bash. How about "-zswap"? This does not require special quoting in bash. > > > > > > > > > If everything is good, I'll squash this patch with the original version, > > > (keeping you as a co-developer of the final patch of course), and > > > update the documentation before re-sending everything as v6. > > > > Great! > > > > > > > > Anyway, have a nice Thanksgiving break everyone! Thanks for > > > taking the time to review my patch and discuss the API with me! > > > > My pleasure to discuss the swap with you. We should do the online > > "swap meet" and invite other developers who are interested in the swap > > area as well. > > I look forward to this meeting! I'd love to discuss more about (z)swap > development (and more generally, multi-tier memory management). Let me arrange one then. I am thinking maybe every second week of the month. That can avoid thanksgiving, christmas and new year. Let me throw in some more ideas: writing compressed zswap data to SSD without swap cache. > Generic page promoter/demoter that takes into account workload > (cgroup), access recency (LRU + generations)/frequency, and tier > characteristics (latency, bandwidth, etc.) will be awesome to explore! Sounds great. Looking forward to it. Chris
