This is also posted to DAMON mailing list.

It is a bit late, but let me share my retrospect of DAMON development for 2025, before my memory goes away. The yearly retrospects for 2022 [1], 2023 [2] and 2024 [3] are also available.

Summary

2025 was the busiest year for DAMON development of its history. 33 people made 390 commits for DAMON in 2025. Those numbers are 65 % and 157 % increase from those of 2024. Before 2025, 2022 was the busiest year that 32 people made 210 commits for DAMON.

Contributions from Meta except myself (observabilities for hugepages and LRU), Micron (access-aware runtime memory interleaving for CXL memory), Huawei (arm32 LPAE support), SK hynix (memory tiering related fixes) and individuals (important fixes and refactoring) were impressive and notable.

Major motivations that led DAMON development in 2025 were self-tuning, system/fleet observability and memory tiering.

Events

There were many events in 2025. Introducing only a few notable ones. A more exhaustive list of events is also available at DAMON project site [4].

Adoptions

In April, OpenSuse kernels build-enabled [5] DAMON.

In June, DAMON was build-enabled on mainline by default [6], and reverted [7] by Linus Torvalds.

In October, DAMON module for system/fleet-wide access monitoring (DAMON_STAT) has build-enabled [8] on Debian kernels.

DAMON Feature Releases

Many DAMON features have developed and landed on the mainline in 2025. Listing only a few of those that stands out to me. A more exhaustive list of features is available on DAMON user-space tool’s DAMON features list [9].

In February, Linux 6.14-rc1 was released, with page level monitoring [10] feature.

In April, Linux 6.15-rc1 was released. Usama and Naht from Meta contributed huge pages [11] and LRU pages [12] monitoring/operation extensions. The release also introduced the monitoring intervals goal auto-tuning [13], which made DAMON just work.

In June, Linux 6.16-rc1 was released, with DAMON’s memory tiering automation support [14]. The feature is not only for memory tiering but general per-NUMA utilization based access-aware system operations automation, though.

In August, Linux 6.17-rc1 was released. In this release, Bijan and Ravi from Micron contributed access-aware runtime memory interleaving features [15] for their CXL memory tiering solution. A module for fleet-wide access monitoring (DAMON_STAT) [16] is also introduced.

In October, Linux 6.18-rc1 was released. In this release, Quanmin from Huawei contributed [17] arm32 Large Physical Address Extension support. Yueyang Pan from Meta contributed [18] huge pages observability on virtual address space.

In December, Linux 6.19-rc1 was released. In this release, per-node per-memcg memory utilization based DAMOS automation [19] is introduced. Motivation of the feature was per-cgroup memory tiering.

Presentations

2025 was an interesting year in terms of presentation, since I found two presentations from someone other than myself that introduced DAMON use cases.

In October, Asier from Huawei presented a DAMON use case for THP [20] at OSSummit EU in August.

In November, Ravi from Micron presented a DAMON use case for CXL memory tiering aiming both latency and bandwidth improvements [21] at Linux Memory Hotness and Promotion meeting.

I also led some sessions at conferences in 2025.

In February, I presented DAMON in whole, at FOSDEM [22].

In March, I led two sessions discussing DAMON development status and future at LSF/MM/BPF [23].

In June, I introduced DAMON’s new intervals autotuning feature [24] at OSSummit NA.

In September, I introduced DAMON’s monitoring mechanism and usage [25] at Kernel Recipes.

In December, I led two DAMON discussion sessions [26,27] and one presentation [28] at LPC special-purpose memory micro-conference, system monitoring micro-conference, and refereed track, respectively.

Statistics

Like previous yearly retrospects, I ran my script [29] to see DAMON development statistics as below. In 2025, 33 people made 390 commits for DAMON. Huge appreciation to all grateful contributors.

$ ./lazybox/version_control/authors.py ./linux --skip_merge_commits \
        --linux_subsystems DAMON --year 2025
1. SeongJae Park <sj@kernel.org>: 310 commits
2. Quanmin Yan <yanquanmin1@huawei.com>: 10 commits
3. Bijan Tabatabai <bijantabatab@micron.com>: 10 commits
4. Enze Li <lienze@kylinos.cn>: 8 commits
5. Sang-Heon Jeon <ekffu200098@gmail.com>: 8 commits
6. Honggyu Kim <honggyu.kim@sk.com>: 6 commits
7. Usama Arif <usamaarif642@gmail.com>: 6 commits
8. Akinobu Mita <akinobu.mita@gmail.com>: 3 commits
9. Yueyang Pan <pyyjason@gmail.com>: 2 commits
10. Yunjeong Mun <yunjeong.mun@sk.com>: 2 commits
11. Nhat Pham <nphamcs@gmail.com>: 2 commits
12. David Hildenbrand <david@redhat.com>: 2 commits
13. Arnd Bergmann <arnd@arndb.de>: 1 commits
14. Dan Carpenter <dan.carpenter@linaro.org>: 1 commits
15. Lorenzo Stoakes <lorenzo.stoakes@oracle.com>: 1 commits
16. Balbir Singh <balbirs@nvidia.com>: 1 commits
17. Swaraj Gaikwad <swarajgaikwad1925@gmail.com>: 1 commits
18. Lokesh Gidra <lokeshgidra@google.com>: 1 commits
19. jianyun.gao <jianyungao89@gmail.com>: 1 commits
20. Alexandre Ghiti <alexghiti@rivosinc.com>: 1 commits
21. Qianfeng Rong <rongqianfeng@vivo.com>: 1 commits
22. Stanislav Fort <stanislav.fort@aisle.com>: 1 commits
23. Bjorn Helgaas <bhelgaas@google.com>: 1 commits
24. Nathan Gao <zcgao@amazon.com>: 1 commits
25. Linus Torvalds <torvalds@linux-foundation.org>: 1 commits
26. Thushara.M.S <thusharms@gmail.com>: 1 commits
27. Su Hui <suhui@nfschina.com>: 1 commits
28. Taotao Chen <chentaotao@didiglobal.com>: 1 commits
29. Seongjun Kim <bus710@gmail.com>: 1 commits
30. Marcelo Moreira <marcelomoreira1905@gmail.com>: 1 commits
# 33 authors, 390 commits in total

It is a dramatic increase of the amount from that of 2024. In 2024, 20 people made 157 commits. So 65 % increase of developers, and 148 % increase of commits.

2025 was not just busier than 2024. It was the busiest year in DAMON’s history. The stats for the whole history of DAMON are as below.

$ ./lazybox/version_control/authors.py ./linux --skip_merge_commits \
        --linux_subsystems DAMON --year 2024
[...]
# 20 authors, 157 commits in total

$ ./lazybox/version_control/authors.py ./linux --skip_merge_commits \
        --linux_subsystems DAMON --year 2023
[...]
# 25 authors, 180 commits in total

$ ./lazybox/version_control/authors.py ./linux --skip_merge_commits \
        --linux_subsystems DAMON --year 2022
[...]
# 32 authors, 210 commits in total

$ ./lazybox/version_control/authors.py ./linux --skip_merge_commits \
        --linux_subsystems DAMON --year 2021
[...]
# 11 authors, 75 commits in total

2022 was the busiest year where 32 developers made 210 commits. Compared to the year, the increase of the number of developers (3.12 %) is trivial. But the increase of the number of commits (85.71 %) is still impressive.

Again, huge appreciation to all grateful developers!

DAMON User-space Tool

Development of the DAMON user-space tool was also busier than 2024. 12 people made 1,309 commits in 2025. In 2024, 8 people made 1,031 commits. Note that the 2024 statistic counts me twice. Again, huge appreciation to all grateful developers!

$ ./lazybox/version_control/authors.py ./damo --year 2025
1. SeongJae Park <sj@kernel.org>: 1291 commits
2. Bijan Tabatabai <bijantabatab@micron.com>: 3 commits
3. Usama Arif <usamaarif642@gmail.com>: 3 commits
4. Andrew Paniakin <apanyaki@amazon.com>: 2 commits
5. Bijan Tabatabai <btabatabai@wisc.edu>: 2 commits
6. Wu Cheng Han <hank20010209@gmail.com>: 2 commits
7. Michel Lind <salimma@fedoraproject.org>: 1 commits
8. SeungSu Baek <ssbaek@korea.ac.kr>: 1 commits
9. Bijan Tabatabai <bijan311@gmail.com>: 1 commits
10. Nhat Pham <nphamcs@gmail.com>: 1 commits
11. wangchuanguo <wangchuanguo@inspur.com>: 1 commits
12. Akinobu Mita <akinobu.mita@gmail.com>: 1 commits
# 12 authors, 1309 commits in total

$ ./lazybox/version_control/authors.py ./damo --year 2024
1. SeongJae Park <sj@kernel.org>: 753 commits
2. SeongJae Park <sj38.park@gmail.com>: 264 commits
3. Mithun Veluri <velurimithun38@gmail.com>: 4 commits
4. Honggyu Kim <honggyu.kim@sk.com>: 3 commits
5. m8 <umusasadik@gmail.com>: 2 commits
6. Yunjeong Mun <yunjeong.mun@sk.com>: 2 commits
7. Akinobu Mita <akinobu.mita@gmail.com>: 1 commits
8. Alex Rusuf <yorha.op@gmail.com>: 1 commits
9. Piyush Thange <pthange19@gmail.com>: 1 commits
# 9 authors, 1031 commits in total

Paper Citations

I published two academic papers introducing DAMON in 2019 [14] and 2022 [15]. The number of citations for the two papers continued its exponential increase, as below.

2019-published paper: 10 (2024) -> 18 (2025)
2022-published paper: 7  (2024) -> 14 (2025)

Conclusion

So, 2025 was the busiest year of DAMON development in its history. That was motivated by automation, observability, and memory tiering needs. Meta, Micron, Huawei, SK hynix and individuals made the major selfish ;) and grateful contributions.

References

Summary#

Events#

Adoptions#

DAMON Feature Releases#

Presentations#

Statistics#

DAMON User-space Tool#

Paper Citations#

Conclusion#

References#