Recently started learning how memory cgroup in the Linux kernel works, so started writing articles about it. The first posting for my English blog vmscan.org!

A brief look at memory cgroup controller introduced in the Linux kernel v2.6.25.
https://vmscan.org/a-brief-look-at-memory-cgroup-controller-introduced-in-linux-kernel-v2625

I have been spending seven hours every Saturday studying the Linux kernel with a study group for years. It's been fun, but over time, I started to feel like I wasn’t spending my time wisely. I have to accept the fact that I don’t have enough time to regularly look at anything outside of MM.

I tried GPT-o3 (which uses 'advanced reasoning') to review slab patches to see if it works, and it generated many false comments. :P Less advanced than I expected.

Spot on advice for any field.

For gym motivation is useless, it's all discipline, your test is on a day when you 100% hate it and want to do ANYTHING ELSE.

Music is my hobby but barely done any, because it is work really, a different kind, but if you want to get anywhere with it, you have to have the same discipline.

But I plan to apply the same gym-like discipline to that to get what I want out of it.

And of course this goes for kernel work too, obviously.

https://www.youtube.com/watch?v=4pw1tmGh3dk

Blogging time after a long time.
/me again realizes that things not documented are quickly reclaimed from memory.

Oh, I didn't know a CVE can be assigned to my bug fix without me requesting or realizing it. I thought (despite not being a security expert) it was not a 'fun' bug to exploit for attackers.

https://nvd.nist.gov/vuln/detail/CVE-2025-21860

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

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 :)

This book serves as a guiding light in navigating the increasingly complex memory management subsystem. A must-have book if you're interested in memory management!

I'mq glad to see the author's long effort finally paying off. Finally available for preorder 👏.

Already ordered one!

https://fosstodon.org/@ljs/114004492112728241

Forbes is warning us that Android phones are under severe risk due to a kernel vulnerability:

https://www.forbes.com/sites/zakdoffman/2025/02/03/google-warns-all-android-users-your-phone-is-now-at-risk/

This comes from Google's Android security bulletin for February:

https://source.android.com/docs/security/bulletin/2025-02-01

...which informs us that "There are indications that CVE-2024-53104 may be under limited, targeted exploitation". The vulnerability in question, though, is CVE-2024-53104:

https://lwn.net/ml/all/2024120232-CVE-2024-53104-d781@gregkh

...which is in the uvcvideo camera driver. Either I'm missing something badly, or the only way to exploit this would be to plug a malicious camera device into the phone. I can see why they would want to fix this, but I'm not sure it's a red-alert situation for most of us?

Pretty much every serious photographer here tries to capture photos of the #volcano and the #northernlights together. Sometimes, they succeed quite well ;) Photos from Wioleta Gorecka, taken near Reykjanesvíti.

#Iceland #Eruption

Intel SNC6 Sub-NUMA Clustering Support With Linux 6.13

A few weeks back I wrote about Intel engineers preparing SNC6 support with Linux for six nodes per L3 cache. That was the first time hearing of SNC6 with SNC 1/2/3/4 sub-NUMA clustering modes being more common. That support is now ready for merging with the Linux 6.13 kernel cycle...
https://www.phoronix.com/news/Intel-SNC6-For-Linux-6.13

omg sir @vbabka you made the shittiverse go crazy!! 🎖️

Definitely a day best spent outdoors

Famous l337 hax0r Vmastilil Bobka @vbabka SPED UP BASED PENGUIN OS BY 4000%!!!!

Check it out and smash the like button + subscribe at

https://www.youtube.com/watch?v=m9dZkRwWEj8

Since the report of 3888.9% performance improvement made it not only to Phoronix (no surprises there) but is now also the subject of at least two youtube videos, where one has 212k views at this point (just wow), I've decided to explain in some detail why the benchmark is in this context completely bogus, and that people missed the very same report also contains a 9% regression in another benchmark (which may be actually less bogus :)
Hope someone finds this useful. http://lore.kernel.org/all/3b09bf98-9bd4-465b-b9c5-5483a6261dc7%40suse.cz
The youtube videos: https://www.youtube.com/watch?v=m9dZkRwWEj8
https://youtu.be/OvLEx6fPVrg

Oh no I'm gaining weight

Unintentionally messed up @vbabka 's tree tree by doing last-minute reviews :(

x.x.x.x - - [10/Nov/2024:00:02:37 +0000] "GET / HTTP/1.1" 301 162 "-" "okhttp/4.9.0"

You know what’s interesting about this log line? It repeats 56,686,963 times in www.kernel.org logs for yesterday, across 4 nodes. That’s about 700 times a second, and this has been going on for months.

These requests aren’t intentionally malicious – they issue a simple GET /, receive their 301 redirect, and terminate the connection. From what I can tell, this is some kind of appliance or software installed on mobile clients that uses “can I reach www.kernel.org” as a network test.

This wouldn’t be that big of a deal – a single plaintext “GET /“ that triggers an immediate 301 is very cheap for us to generate, but the number of these requests has been steadily growing.

If you have any idea what this is and how to make it stop, please reach out?