Hello, The last major Linux version of 2021, v5.15, was the debut of DAMON. After the release, one more thankful year of DAMON development has passed. I'd like to share some major events and statistics of DAMON development that we had in 2022, and say thank you to the community. Summary ======= 2022 was a year of active and healthy DAMON development. Seven new DAMON major features were delivered to users. Some of those were featured in articles and academic papers. It was possible thanks to the DAMON community. The community has expanded with its own mailing list and an open bi-weekly chat series. 40 people contributed their great code to DAMON via making their 275 commits merged into the mainline. About 33% of the commits were made by Amazon-external contributors. The amount of DAMON changes in 2022 (v5.15..v6.2-rc1) was not that tiny compared to other subsystems. About 0.2% of the commits for whole Linux tree was for DAMON. Among the changes for DAMON's parent subsystem, mm, about 8% of commits and 14% of lines of changes were made for DAMON. Key Events ========== In January of 2022, v5.16, the first major Linux version of 2022, has released with major DAMON features including - DAMON-based Operation Schemes, - Physical address space monitoring support, - DAMOS quota/priorities/watermarks, and - Data Access-aware Reclaim module (DAMON_RECLAIM). In April, DAMON and DAMON_RECLAIM were merged[1] into Android. In May, v5.18 was released with DAMON sysfs interface, which is aimed to be the flexible and stable DAMON interface for long term usage. We also made a mailing list which is dedicated for DAMON development (damon@xxxxxxxxxxxxxxx). In June, we presented DAMON-related works in an academic conference, HPDC[2]. In July, v5.19 as released with DAMON online tuning feature. This opened the chance for more optimal and automated tuning of DAMON. DAMON has also featured[3] on Embedded Linux Conference'22 keynote. In August, DAMON community started its bi-weekly virtual chat series[4]. DAMON-based Proactive LRU-lists Sorting patchset, which reduces about 20% of pressure stall time, has merged into the mainline and featured by LWN[5]. In September, DAMON's current status and future plans were presented[6] at KernelSummit. In October, v6.0 was released with DAMON-based Proactive LRU lists sorting. We also had a first in-person DAMON community meetup[7] in LPC. In November and December, DAMOS tried regions patchset, which makes query-like efficient monitoring results collection available, and DAMOS filters patchset, which allows finer tuning and cgroups support of DAMON-based memory managements, have developed. The first one has merged in v6.2-rc1 in December. The second one will hopefully be merged into v6.3 in 2023. [1] https://android.googlesource.com/kernel/common/+/0496c13ded02bd72426d189b777bf303fe490f62 [2] https://www.amazon.science/publications/daos-data-access-aware-operating-system [3] https://lwn.net/Articles/899742/ [4] https://lore.kernel.org/damon/20220810225102.124459-1-sj@xxxxxxxxxx/ [5] https://lwn.net/Articles/905370/ [6] https://lpc.events/event/16/contributions/1224/ [7] https://lpc.events/event/16/contributions/1388/ Development Statistics ====================== To appreciate and list all names of people who made DAMON available, and to quantify what 2022 was for DAMON development, I collected some numbers using my humble and buggy scripts. The scripts are available as open source[1,2]. [1] https://github.com/sjp38/lazybox [2] https://git.kernel.org/sj/damon-hack/h/master Contributors ------------ According to the humble script, 40 people have contributed to DAMON development in 2022 (v5.15..v6.2-rc1). $ ./lazybox/git_helpers/authors.py ./linux --commits_range v5.15..v6.2-rc1 \ --skip_merge_commits --max_nr_authors 40 --files mm/damon/ \ include/trace/events/damon.h include/linux/damon.h \ Documentation/admin-guide/mm/damon/ Documentation/mm/damon/ \ Documentation/vm/damon/ \ Documentation/ABI/testing/sysfs-kernel-mm-damon \ tools/testing/selftests/damon 1. SeongJae Park <sj@xxxxxxxxxx>: 192 commits 2. Xin Hao <xhao@xxxxxxxxxxxxxxxxx>: 19 commits 3. Kaixu Xia <kaixuxia@xxxxxxxxxxx>: 15 commits 4. Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>: 5 commits 5. Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>: 4 commits 6. Changbin Du <changbin.du@xxxxxxxxx>: 4 commits 7. Yang Yingliang <yangyingliang@xxxxxxxxxx>: 2 commits 8. SeongJae Park <sjpark@xxxxxxxxx>: 2 commits 9. Rong Tao <rongtao@xxxxxxxx>: 1 commits 10. Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>: 1 commits 11. Jason A. Donenfeld <Jason@xxxxxxxxx>: 1 commits 12. Dawei Li <set_pte_at@xxxxxxxxxxx>: 1 commits 13. Yajun Deng <yajun.deng@xxxxxxxxx>: 1 commits 14. Levi Yun <ppbuk5246@xxxxxxxxx>: 1 commits 15. Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>: 1 commits 16. Kenneth Lee <klee33@xxxxxx>: 1 commits 17. Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>: 1 commits 18. Badari Pulavarty <badari.pulavarty@xxxxxxxxx>: 1 commits 19. Kairui Song <kasong@xxxxxxxxxxx>: 1 commits 20. Jianglei Nie <niejianglei2021@xxxxxxx>: 1 commits 21. Gautam <gautammenghani201@xxxxxxxxx>: 1 commits 22. Mike Rapoport <rppt@xxxxxxxxxxxxx>: 1 commits 23. Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>: 1 commits 24. Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>: 1 commits 25. Gautam Menghani <gautammenghani201@xxxxxxxxx>: 1 commits 26. Jiapeng Chong <jiapeng.chong@xxxxxxxxxxxxxxxxx>: 1 commits 27. Hailong Tu <tuhailong@xxxxxxxxx>: 1 commits 28. Yu Zhe <yuzhe@xxxxxxxxxxxx>: 1 commits 29. Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>: 1 commits 30. Jonghyeon Kim <tome01@xxxxxxxxxx>: 1 commits 31. tangmeng <tangmeng@xxxxxxxxxxxxx>: 1 commits 32. Miaohe Lin <linmiaohe@xxxxxxxxxx>: 1 commits 33. Guoqing Jiang <guoqing.jiang@xxxxxxxxx>: 1 commits 34. Yihao Han <hanyihao@xxxxxxxx>: 1 commits 35. Jakub Kicinski <kuba@xxxxxxxxxx>: 1 commits 36. Colin Ian King <colin.i.king@xxxxxxxxxxxxxx>: 1 commits 37. Rongwei Wang <rongwei.wang@xxxxxxxxxxxxxxxxx>: 1 commits 38. Rikard Falkeborn <rikard.falkeborn@xxxxxxxxx>: 1 commits 39. Colin Ian King <colin.king@xxxxxxxxxxxxx>: 1 commits 40. Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>: 1 commits # 40 authors, 275 commits in total Please note that there were many more unsung hero contributors who contributed valuable inputs, discussions, and many more things for DAMON development. So shame that I cannot put everyone's name here. Thank you so much to all awesome contributors! Contributions from non-maintainer --------------------------------- The maintainer, SJ (sj@xxxxxxxxxx), has driven the development of DAMON, but the help from the community was huge. About 33% of DAMON commits have made by people other than the maintainer. $ ./damon-hack/stat_damon_portion_community_commits.sh ./linux ./damon-hack/stat_branches_2022 range from_sj non_sj non_sj_portion v5.15..v5.16 50 13 20.63% v5.16..v5.17 16 10 38.46% v5.17..v5.18 26 10 27.78% v5.18..v5.19 23 7 23.33% v5.19..v6.0 15 14 48.28% v6.0..v6.1 33 36 52.17% v6.1..v6.2-rc1 28 6 17.65% v5.15..v6.2-rc1 191 95 33.22% Portion of DAMON Commits in MM and Linux ---------------------------------------- To show how much change DAMON made to its parent subsystem, MM, and whole Linux, I counted the number of commits that touched mm/damon, mm/ and any file of the Linux tree in 2022 releases (v5.15..v6.2-rc1). Note that I counted changes touching only mm/damon/ and mm/ for DAMON and MM appropriately (doesn't count changes for documents, headers, tests, etc), for simplicity. According to the buggy and humble script, about 8% of MM commits, and 0.2% of Linux commits were made for DAMON. $ ./damon-hack/stat_damon_portion_nr_commits.sh ./linux ./damon-hack/stat_branches_2022 range damon mm damon/mm linux damon/linux v5.15..v5.16 45 307 14.66% 14190 0.32% v5.16..v5.17 17 223 7.62% 13038 0.13% v5.17..v5.18 29 448 6.47% 14954 0.19% v5.18..v5.19 24 399 6.02% 15134 0.16% v5.19..v6.0 15 283 5.30% 15402 0.10% v6.0..v6.1 61 536 11.38% 13942 0.44% v6.1..v6.2-rc1 20 250 8.00% 13687 0.15% v5.15..v6.2-rc1 211 2446 8.63% 100347 0.21% By Number of Lines ------------------ I further counted the portion of the number of changed lines. Didn't count that for Linux here due to the slow speed of the script. Please also note that I count changes touching only mm/damon/ and mm/ as same to above case. The script argues about 14% of the changes lines for MM subsystem were for DAMON. $ ./damon-hack/stat_damon_portion_lines.sh ./linux ./damon-hack/stat_branches_2022 range damon mm damon/mm v5.15..v5.16 2157 8503 25.37% v5.16..v5.17 324 9370 3.46% v5.17..v5.18 3462 16288 21.25% v5.18..v5.19 929 10185 9.12% v5.19..v6.0 870 8665 10.04% v6.0..v6.1 1752 25844 6.78% v6.1..v6.2-rc1 3309 10544 31.38% v5.15..v6.2-rc1 12803 89399 14.32% Conclusion ========== DAMON community delivered a number of important features and quite a number of changes to the world via the collaboration between the 40 great contributors. I would call 2022 as one of the greatest years of DAMON development. Huge thanks to you again, DAMON community. Looking forward to continuing our journey in 2023. Hope you all enjoy the remaining holidays and happy new year! Thanks, SJ
