Preparing DAMON for future memory-management problems

The Data Access MONitor (DAMON) subsystem provides access to detailed memory-management statistics, along with a set of tools for implementing policies based on those statistics. An update on DAMON by its primary author, SeongJae Park, has been a fixture of the Linux Storage, Filesystem, Memory-Management, and BPF Summit for some years. The 2025 Summit was no exception; Park led two sessions on recent and future DAMON developments, and how DAMON might evolve to facilitate a more access-aware memory-management subsystem in the future.
数据访问监控器（DAMON）子系统提供了详细的内存管理统计信息，以及一套基于这些统计信息实施策略的工具。DAMON 的主要作者 SeongJae Park 多年来一直在 Linux 存储、文件系统、内存管理和 BPF 峰会上进行更新汇报。2025 年的峰会也不例外；Park 主持了两个关于 DAMON 近期和未来发展方向的会议，并讨论了 DAMON 如何演进以促进更具访问感知能力的内存管理子系统。

A status update
状态更新

The first session was dedicated to updating participants on what is happening with DAMON; Park started by thanking all of the members of the development community who have contributed changes. DAMON, he reminded the group, provides access-pattern information for both virtual and physical address spaces, and allows the specification of access-aware operations to be performed. Thus, for example, an administrator can set up a policy to reclaim all pages that have been idle for at least two minutes. DAMON is increasingly used for this sort of proactive reclaim by large providers like Amazon's AWS, and in various memory-tiering settings.
第一个会议专门用于向与会者通报 DAMON 的最新进展；Park 开场时感谢所有为该项目贡献过修改的开发者社区成员。他提醒大家，DAMON 提供了虚拟地址空间和物理地址空间的访问模式信息，并允许执行基于访问感知的操作。例如，管理员可以设置策略，回收所有至少两分钟未被访问的页面。像 Amazon AWS 这样的主流云服务提供商越来越多地在主动内存回收和内存分层场景中使用 DAMON。

Major changes to DAMON since the 2024 update include a new tuning guide. Page-level monitoring has been enhanced to expose information about huge pages that can be used in policy filters. Shakeel Butt asked whether this filter would select specific huge pages, or those within a given region; Park said that the filter can be applied to any address range. DAMON can provide more detailed information, including what proportion of a given region has passed a filter. There are filters for huge-page size and whether pages are on the active least-recently-used (LRU) list.
自 2024 年更新以来，DAMON 的主要变化包括新增了一份调优指南。页面级别的监控得到了增强，现在可以揭示有关巨页的信息，并可用于策略过滤器中。Shakeel Butt 问该过滤器是选择特定巨页，还是选择某一区域内的巨页；Park 回答说过滤器可以应用于任意地址范围。DAMON 还能提供更详细的信息&#x