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Maintaining DAMON (https://damonitor.github.io). All opinions are my own.
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sj

I finally realized that I cannot implement one access pattern visualization that fits all. Hence next DAMON user-space tool release will contain programmable visualization feature. Users can program their access pattern visualization in Python code, as a script or interactively on the Python interpreter.

https://github.com/damonitor/damo/blob/d0eb41035db1a870d482a14087afda0196c5980b/USAGE.md#damo-report-access-programming-visualization

#linux #kernel #damon #damo
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sj

Edited 2 days ago
Yet another DAMON-citation from a HCDS'25 paper is found. The paper discusses h/w-based CXL coherency management.

https://www.pure.ed.ac.uk/ws/portalfiles/portal/497211278/XingandBarbalaceHDCS2025RethinkingApplications_AddressSpace.pdf

#linux #kernel #damon #cxl #hcds #academic
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sj

@LWN LWN made an excellent summary of the two DAMON sessions that we had at LSFMM+BPF 2025: https://lwn.net/Articles/1016525/

#linux #kernel #damon #lsfmmbpf #lwn

RE: https://fosstodon.org/@LWN/114313949278265552
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LWN@fosstodon.org

LWN.net

[$] 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. [...]

https://lwn.net/Articles/1016525/

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DAMON talk for OSSummit North America 2205 has been accepted and scheduled[1]. The talk will present DAMON's two auto-tuning features for access monitoring and access-aware system operations.

[1] https://sched.co/1zfmE

#linux #kernel #damon #ossummit #ossummitna
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sj

An EuroSys'25 paper for proactive demotion on tiered memory managment is published. It also shares their evaluation of a DAMON-based tiering approach that is being used by HMSDK.

https://dl.acm.org/doi/10.1145/3689031.3717471

#linux #kernel #damon #eurosys
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sj

Edited 18 days ago
MM pull request[1] for Linux 6.15-rc1 is merged. I'd summarize DAMON changes that merged with the pull request as below.

- Monitoring intervals auto-tuning
- Extending DAMOS filter types for hugepage, LRU-[in]active page, and [un]mapped pages
- DAMOS allow filters behavior improvement
- Important cleanups and fixes of code and documents

There are many more interesting changes, too. I highly recommend reading Andrew Morton's great summary on the pull request mail!

[1] https://lore.kernel.org/20250330165732.f4c1493615375623f67e38eb@linux-foundation.org/

#linux #kernel #damon
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sj

Numbers are numbers, but seeing my name on the "Most active 6.14 developer" list[1] is a grateful moment.

[1] https://lwn.net/Articles/1013892/

#linux #kernel #damon #lwn
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phoronix@masto.ai

Phoronix

DAMON Self-Tuned Memory Tiering Shows Nice Improvement For Linux Servers

Linux developer SeongJae Park has posted a set of patches for the Linux kernel's wonderful DAMON code to provide for self-tuned memory tiering that "just works" and is racking up some nice performance wins...
https://www.phoronix.com/news/DAMON-Self-Tuned-Memory-Tiering

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Edited 1 month ago
I just posted an RFC patch series for making DAMON-based memory tiering self-tuned and just works. It contains evaluation of DAMON-based memory tiering that shows 4.42 % performance improvement over baseline and ~10% improvement over NUMA Balancing in memory tiering mode under a setup.

[1] https://lore.kernel.org/20250320053937.57734-1-sj@kernel.org

#linux #kernel #damon
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'damo report heatmap' frequently confused users due to its internal map drawing target area selection. I implemented a feature for making it easier to control, and posted a blog for the problem and the new feature: https://damonitor.github.io/posts/why_the_heatmap_is_not_showing_the_expected_access_patterns/

#damo #faq #damon #linux #kernel
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monsieuricon

K. Ryabitsev 🍁

Edited 1 month ago
PSA: please don't use git.kernel.org directly for your CI needs. It is not viable for us to provide enough capacity to withstand dozens of CI nodes all trying to clone linux.git at the same time for multiple CI farms. You *will* get ip-blocked. Please set up a local mirror and hit that instead.
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Edited 1 month ago
I just posted[1] DAMON monitoring intervals auto-tuning patch series without RFC tag. It is now queued on mm-unstable for 6.15-rc1. This version also includes its test results on a real-world server workload. To quote the conclusion part of the evaluation:

"The auto-tuning feature was able to adaptively react to the
dynamic access patterns of the workload and reliably provide consistent
monitoring results without manual human interventions. Also, the
auto-tuning made DAMON consumes only necessary amount of resource for
the required quality."

[1] https://lore.kernel.org/20250303221726.484227-1-sj@kernel.org

#linux #kernel #damon
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paulmckrcu

Paul E. McKenney

It is my honor to be designated as Godfather of the 2025 edition of Kernel Recipes. The conference organizers made it quite clear that they would like some focus on increasing the speaking skills of the presenters. This blog series is a first step in that direction: https://people.kernel.org/paulmck/kernel-recipes-2025
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LWN@fosstodon.org

LWN.net

A change in maintenance for the kernel's DMA-mapping layer

https://lwn.net/Articles/1011819/

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An academic paper showing DAMON-based memory tiering can be further improved using h/w-assisted promotion has been published: https://uu.diva-portal.org/smash/get/diva2:1927657/FULLTEXT01.pdf

#linux #kernel #damon #paper
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ljs@fosstodon.org

Lorenzo Stoakes

Very happy to announce my book The Linux Memory Manager is now available to pre-order at

https://nostarch.com/linux-memory-manager

It's a comprehensive 1,300 page exploration of how memory functions in Linux that goes into great depth on the subject, and is the first book of its kind for 20 years :)

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vbabka@mastodon.social

Vlastimil Babka 🇨🇿🇪🇺🇺🇦

Well well, look what the cat dragged in
https://nostarch.com/linux-memory-manager

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osandov@fosstodon.org

Omar Sandoval

I just published a hands-on tutorial walking through a real kernel bug investigation using drgn, both as a video: https://youtu.be/s5TvkvMiV_M and a writeup: https://drgn.readthedocs.io/en/latest/tutorials/blk_rq_qos_crash.html. It includes a core dump that you can download to follow along. It covers stack traces, local variables, and a few drgn helpers for identifying unknown addresses and structures. Check it out!

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I just posted an RFC patch series[1] for automatically tuning DAMON monitoring intervals, like auto-exposing cameras. Hopefully this will mitigate one of big blockers for making DAMON just works and runs on all Linux machines by default.

[1] https://lore.kernel.org/20250213014438.145611-1-sj@kernel.org

#linux #kernel #damon
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