In 2021, DAMON, a data monitoring access framework developed by Amazon, was successfully merged into Linux Kernel 5.15; since then, more related functions have been gradually added. This year, Amazon engineers are responsible for about two-thirds of DAMON activities, while more independent developers and developers from other organizations continue to participate. Amazon’s SeongJae Park published an annual report detailing DAMON’s event highlights for 2022.

Thanks to the community, a total of seven new DAMON major features will be delivered in 2022. There were 275 commits merged into the mainline from 40 contributors, and about 33% of the commits were made by Amazon-external contributors. DAMON modifications in 2022 (v5.15…v6.2-rc1) are not minor compared to other subsystems. About 0.2% of the commits in the entire Linux tree are for DAMON. About 8% of the commits and 14% of the changed lines in DAMON’s parent subsystem mm were for DAMON.

Some key events include:

• In January 2022, with the arrival of the first major Linux version v5.16 of the new year, major DAMON features were released: including DAMON-based Operation Schemes, physical address space monitoring support, DAMOS quota/priorities/watermarks, and data access Aware Recycling Module (DAMON_RECLAIM).
• In April, DAMON and DAMON_RECLAIM were merged into Android.
• In May, Linux 5.18 introduced the sysfs interface, aiming to become a flexible and stable DAMON interface that can be used for a long time. There is also a mailing list dedicated to DAMON development (damon@lists.linux.dev).
• In July, Linux 5.19 was released with DAMON online tuning function.
• In August, the DAMON-based Proactive LRU-lists Sorting patchset reduced the pressure stall time by about 20%.
• In October, in Linux 6.0, DAMON added DAMON-based Proactive LRU lists sorting.
• In November and December, DAMOS tried regions patchset, which provides efficient collection of monitoring results like queries; and DAMOS filters patchset, which allows finer tuning and cgroups support for DAMON-based memory management. The first was merged into v6.2-rc1 in December, and the second is expected to be merged into v6.3 in 2023.

See the kernel mailing list for more details.