This is also posted to the mailing list.

Hello community,

This newsletter covers DAMON features that landed on the mainline, queued for the mainline, development statistics and misc events that were interesting to me that happened in v7.1-rc1..v7.2-rc1 time period (2026-04-26..2026-06-28).

The newsletter covering the previous release cycle (v7.0-rc1..v7.1-rc1) is also available [1].

TLDR

The last development cycle for DAMON was the busiest cycle of its mainline history (~5 years, since 2021 September). 12 Authors landed 106 DAMON patches for a number of changes including 7 new features on the mainline. A roadmap for extending DAMON to utilize AMD IBS, Intel PEBS like h/w features and do per-CPUs/threads/reads/writes monitoring is made.

Changes Landed on 7.1

All changs that were landed on v7.1-rc1 have successfully landed on v7.1. The changes include selective DAMOS auto-tuning algorithms (commit 8719c59c4b928). Read the newsletter for 7.1-rc1 [1] for more details of the changes.

Chanegs Landed for 7.2

During the 7.2-rc1 merge window, 95 DAMON patches have landed via the MM pull requests [2,3]. Introducing a few of changes that could introduce non-trivial user impacts.

New Features

In the merge window, below user-visible new features are added.

Commit 9138e27a3bc38: “mm/damon: add node_eligible_mem_bp goal metric”
Commit c7ec7d5f6b3d1 “mm/damon: introduce DAMOS failed region quota charge ratio”
Commit 3b9e3cc0405b4 “mm/damon: let DAMON be paused and resumed”
Commit 70d8797c15d64 “mm/damon/reclaim,lru_sort: monitor all system rams by default”
Commit 0453f857eb32c “mm/damon/reclaim: support monitoring intervals auto-tuning”
Commit 3a0bc9568c354 “mm/damon/stat: add kdamond_pid parameter”.
Commit 45c49d9fd6089 “mm/damon: introduce data attributes monitoring”.

Feature 1 is developed by Ravi at Micron, for their auto-tuned dynamic DRAM/CXL memory interleaving for memory bandwidth optimization.

Features 2 and 3 make DAMOS be more deterministically controllable.

Features 4-6 improves DAMON modules for easier control and more reliable operations.

Feature 7 introduces the data attributes monitoring, which enables light-weight page level (e.g., cgroup-aware) access monitoring. It will also be the foundation of the ongoing collaboration project.

Deprecation

In the merge window, below change for deprecating one user-visible feature is also merged. It deprecates a directory in DAMON sysfs interface. Users can replace it with its alternatives, ‘core_filters/’ and ‘ops_filters/’ directories. We will continue supporting the deprecated feature for a while, but will eventually remove it. Please update your usages, or request holding the removal if it is really needed for you.

Commit 7e6cc9f954aa3: “mm/damon/sysfs: document filters/ directory as deprecated”

Changes Cooking for >7.3

A number of patches are queued and being developed for 7.3-rc1. My personal tree for those (damon/next) contains 231 downstream patches as of this writing. Not all the patches are aiming to be merged into 7.3-rc1. However, apparently the next cycle will also not be a very idle cycle.

Statistics

Putting simple statistics for the last release period. Tools other than git that are used here for getting the numbers are available [4,5] at GitHub.

In short, this cycle was the busiest cycle of DAMON development history.

Number of DAMON Commits

Eleven DAMON hotfixes have landed on 7.1.

$ git log v7.1-rc1..v7.1 --oneline --no-merges -- \
        mm/damon include/linux/damon.h \
        Documentation/mm/damon/ Documentation/admin-guide/mm/damon/ \
    Documentation/ABI/testing/sysfs-kernel-mm-damon \
        include/trace/events/damon.h samples/damon/
        tools/testing/selftests/damon | wc -l
11

Ninty two DAMON changes have landed on 7.2-rc1 during the merge window.

$ git log v7.1..v7.2-rc1 --oneline --no-merges -- \
        mm/damon include/linux/damon.h \
        Documentation/mm/damon/ Documentation/admin-guide/mm/damon/ \
    Documentation/ABI/testing/sysfs-kernel-mm-damon \
        include/trace/events/damon.h samples/damon/ \
        tools/testing/selftests/damon | wc -l
95

The numbers for the last seven release cycles are like below:

7.1   fixes:  11  7.2   changes:  95
7.0   fixes:  9   7.1   changes:  64
6.19  fixes:  7   7.0   changes:  68
6.18  fixes:  7   6.19  changes:  78
6.17  fixes:  15  6.18  changes:  41
6.16  fixes:  8   6.17  changes:  93
6.15  fixes:  0   6.16  changes:  22

The 6.17 development cycle was the busiest DAMON development cycle in history (~5 years since 5.15). This cycle broke the record.

Contributors

In this cycle, 12 people made 106 grateful DAMON commits on the Linux mainline.

$ ./lazybox/version_control/authors.py ./linux --skip_merge_commits \
        --linux_subsystems DAMON --since v7.1-rc1 --until v7.2-rc1
1. SeongJae Park <sj@kernel.org>: 91 commits
2. Liew Rui Yan <aethernet65535@gmail.com>: 4 commits
3. Maksym Shcherba <maksym.shcherba@lnu.edu.ua>: 2 commits
4. Zenghui Yu <zenghui.yu@linux.dev>: 1 commits
5. Sakurai Shun <ssh1326@icloud.com>: 1 commits
6. niecheng <niecheng1@uniontech.com>: 1 commits
7. Kefeng Wang <wangkefeng.wang@huawei.com>: 1 commits
8. Vineet Agarwal <agarwal.vineet2006@gmail.com>: 1 commits
9. Jiayuan Chen <jiayuan.chen@shopee.com>: 1 commits
10. Asier Gutierrez <gutierrez.asier@huawei-partners.com>: 1 commits
11. Cheng-Han Wu <hank20010209@gmail.com>: 1 commits
12. Ravi Jonnalagadda <ravis.opensrc@gmail.com>: 1 commits
# 12 authors, 106 commits in total

The last lines for the last eight release cycles are like below:

7.2-rc1:   #  12  authors,  106  commits  in  total
7.1-rc1:   #  8   authors,  73   commits  in  total
7.0-rc1:   #  12  authors,  75   commits  in  total
6.19-rc1:  #  10  authors,  85   commits  in  total
6.18-rc1:  #  11  authors,  56   commits  in  total
6.17-rc1:  #  7   authors,  101  commits  in  total
6.16-rc1:  #  5   authors,  22   commits  in  total
6.15-rc1:  #  7   authors,  68   commits  in  total

DAMON user-space tool (damo) also got a significant amount of changes.

$ ./lazybox/version_control/authors.py ./damo --skip_merge_commits \
        --since 2026-04-26 --until 2026-06-28
1. SeongJae Park <sj@kernel.org>: 146 commits
2. Sean Jackson <sjackson@crusoe.ai>: 2 commits
3. Kunwu Chan <kunwu.chan@gmail.com>: 2 commits
4. Zeyu Wang <wangzeyu2024@lzu.edu.cn>: 1 commits
# 4 authors, 151 commits in total

The last line was “1 authors, 123 commits in total” for the last cycle [1]. Both the number of contributors and the number of commits have significantly increased.

Mailing List Traffic

DAMON mailing list was quite busy.

$ hkml list damon --since v7.1-rc1 --until v7.2-rc1 \
        --collapse --stat_only --stdout
# stat for total mails
# 1480 mails, 163 threads, 141 new threads
# 670 patches, 125 series
[...]

The traffic for the last cycle period was like below.

$ hkml list damon --since v7.0-rc1 --until v7.1-rc1 \
        --collapse --stat_only --stdout
# stat for total mails
# 1098 mails, 152 threads, 147 new threads
# 450 patches, 129 series
[...]

The traffic has also sigificantly increased. Since the traffic is not only for the 7.2-rc1 but also for 7.3-rc1, 7.3-rc1 might have even more DAMON changes.

Events

Ravi from Micron landed DAMOS_QUOTA_ELIGIBLE_MEM_BP patch [6] for auto-tuned DRAM/CXL memory dynamic interleaving has finally reached the mainline.

A few DAMON topics were discussed in LSFMMBPF'26. The topics included

update of DAMON developments for CXL and memory tiering and plan for general NUMA management,
a plan for extending DAMON to Data Attributes Monitoring and Operations eNgine that will cover per-cgroup light-weight access monitoring,
a way for extending DAMON to enable per-CPUs/threads/reads/writes monitoring,
ways to use DAMON for huge pages, and
DAMON Enabled Compute Systems (DAMON-X). Refer to LWN’s great article [7] summarizing the discussions.

Akinobu continued [8] perf event based DAMON extension. Ravi implemented [9] h/w sampled access reports that can utilize AMB IBS and Intel PEBS on it. We made a roadmap [10] for making it all upstreamed by LSFMMBPF'27.

Bijan from UW-Madison published a paper [11] for the dynamic memory interleaving for tiered memory system at ISMM'26. Apparently the work was a collaboration between UW-Madison and Micron.

Asier from Huawei continued [12] work on DAMOS auto-tuning goal for THP. Wang Lian shared [13] an RFC patch series and plans for adding mTHP collapse/split management and ARM SPE feedback utilization to DAMON.

DAMON project blog got its first and grateful post contribution [14] from Kunwu Chan, for its TLB policy.

The Chinese Kernel Community organized a meetup [15], with a session for DAMON.

Liew Rui Yan shared [16] their user-space program for auto-tuning of DAMON-based reclamation, dama.

New Letter Subscription

This newsletter series is posted to DAMON mailing list [17] and archived on the project blog [18], for each release. If you want a reliable delivery of this newsletter series to your inbox, subscribing to the mailing list [18] could be an option. If the mailing list traffic is too much, feel free to ask me (send mail to sj@kernel.org) to [b]cc you for each newsletter posting.

References

Thanks, SJ

TLDR#

Changes Landed on 7.1#

Chanegs Landed for 7.2#

New Features#

Deprecation#

Changes Cooking for >7.3#

Statistics#

Number of DAMON Commits#

Contributors#

Mailing List Traffic#

Events#

New Letter Subscription#

References#