Remote

Lorenzo

@ljs@mastodonapp.uk

mastodon 4.6.8

Linux kernel hacker at arm

Co-maintain memory mapping and rmap.

Wrote a book on memory management, pre-order now - https://nostarch.com/linux-memory-manager

Professional cat obsessive.

Obviously speak only for myself, personally...

515 Followers

136 Following

50 Posts

Joined April 28, 2025

Book:

https://linuxmemory.org

Website:

Lorenzo @ljs@mastodonapp.uk

· 2w ago

If you think an LLM series (done responsibly!) is easy or stress-free or some shortcut think again. This build series has AGED ME. Spent probably 30, 40, 50 hours on it now, much of the work really grim - checking stuff manually, rewriting crap. And endless discussion and back and forth and compromises etc. This is the reality of this stuff - engineers are still very much required, effort is still very much required, oversight is still very much required. A tool in the toolbox, a dangerous and easily abused, and also tempting tool that can make you lazy, but still a tool nonetheless.

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Boosted by @DataKnightmare@mastodon.xyz

When I first pushed back on randomly putting LLM configs in the kernel, I was excluded from the conversation. Then when further discussion was had about it, I was excluded from the conversation. Then when I submitted a proposal to the maintainer's summit about AI, I was rejected and excluded from the conversation there. And when documentation was submitted to the kernel, my feedback was ignored and I was excluded from that conversation too. There was literal press about Linus calling me an idiot for it. When I pushed back on a person lying about using LLMs to generate code, I was attacked and contradicted and forced to concede the discussion. And recently, in yet another discussion about LLMs in the kernel, I was excluded from that too. At each point I've had to fight to have my point of view heard. It feels like many people in the kernel community just want to stick their head in the sand about AI slop. But it's not magically going away. Ignore me all you want.

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

Happy to announce that I've joined ARM to work on KVM and core mm :)

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

I do wonder if we're going to lose an entire generation of programmers because of this LLM shit. And that'll cause a massive crisis later (no I don't believe LLMs will ever replace programmers)

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

RE: https://fedi.lwn.net/@lwn/116981089807528342 I'm absolutely devastated by Dan's passing. Though we didn't work together often, I remember him from conferences and on-list where his calm, thoughtful and kind contributions were always welcome. He so often poured cool water on otherwise heated discussions and I admired him a great deal. It's a huge loss for the community and my heart goes out to his family.

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Lorenzo @ljs@mastodonapp.uk

· 1mo ago

Guy slops totally broken series using the cheapest LLM he can find. Guy finds it's broken, blames upstream kernel, slops a totally broken 'fix'. Guy argues back and wastes time of maintainers who keep telling him it's surely his patch. Maintainer goes and finds broken patch and explicitly points out how it's broken. 2026 everybody...! https://lore.kernel.org/all/aphJ7olxr-_VhDKt@gremlin/ https://lore.kernel.org/lkml/aphN94PIAfM3s4vy@gremlin/

lore.kernel.org

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@lkundrak@metalhead.club thanks :) I know I shouldn't care but ape ego makes me a bit upset that my role in these things is just airbrushed from history rather. But I guess the outcomes matter more than attribution...

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

doing review for free on my week between jobs, in case anybody wondered whether I do this for the money ;) Not that review sparks joy, just taking the maintainership seriously (even if I never, ever catch up with my backlog)

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

I have huge stature in the mm community

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

Working for months on your first truly major change in the kernel only for somebody to not only race you but race you with what is very likely to be AI generated code is deeply depressing and demotivating.

And then for the community to not only not back me but push against me... :(

This is about the most demotivating thing that has happened to me in kernel development so far.

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

well fuck, an m5 max macbook, in a vm, builds the kernel faster than a p7 thinkstation.. insane.

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

Replying to

@vbabka@mastodon.social @monsieuricon@social.kernel.org lol inspired by seeing me add 'cheers' which is a legal requirement for British people?

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

The level of entitlement here is fucking astonishing. To clarify - you have no fucking RIGHT to get your series merged or for people to pay attention to it. I have spent many many UNPAID overtime hours doing thankless review, it happens because people endure suffering for the good of the community. Hell a good chunk of full-time paid kernel engineers don't do ANY review. You are owed exactly nothing. And even more so if you send broken crap you were explicitly told not to send! https://lore.kernel.org/all/b00a03d62c53430ca22b3f3c5e5327b5@honor.com/

lore.kernel.org

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

RE: @mpe@fosstodon.org

Yup being a maintainer is thankless as fuck :)

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

Replying to

@lkundrak@metalhead.club @ptesarik@infosec.exchange @vbabka@mastodon.social @monsieuricon@social.kernel.org Petr thought he was trolling me but he was actually celebrating my nation

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@wagi@mastodon.social @ptesarik@infosec.exchange @cainlee@toot.community we're all imposters sir

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@ptesarik@infosec.exchange @wagi@mastodon.social can I say fuck you on here? Because it seems appropriate here

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

2026 is truly my annus horribilis... (so far). EDIT: Minus 2 very good things (new job, arsenal winning PL)

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

Will spend next month focusing on CoW context work as a priority.

I should get some upstreamable movement on that.

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

The slop is tiresome. These days I try to be diplomatic about it but this guy not only copied a previously rejected RFC he left fucking 'Why this matters:' in the commit message I mean fucking seriously https://lore.kernel.org/all/amMPWbcKoXQ1Mxjw@lucifer/

lore.kernel.org

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@lkundrak@metalhead.club look at how happy sir is cc: @vbabka@mastodon.social @ptesarik@infosec.exchange @liskin@genserver.social

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@lkundrak@metalhead.club FINALLY I REST! FINALLY!

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@pelle@veganism.social well to be accurate - anti-AI slop :) I am fine with AI used sensibly, and would be dishonest of me to say otherwise (I use it). I don't personally use it to generate any code though and don't think it's good enough to do so... and sending unacked slop is just disgusting

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

big up @monsieuricon@social.kernel.org THANK YOU for b4. Now actually using it to send series and with claude fixing my dumbasseries from last time I tried I actually managed to use it sanely and it's great :) Was already using on receive side, but b4 review makes that a million times easier love it!! This might actually make my email vaguely less insane to deal with

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@wagi@mastodon.social @ptesarik@infosec.exchange @cainlee@toot.community it's a bitmask, you can be so many things at once young Daniel

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@wagi@mastodon.social @ptesarik@infosec.exchange @cainlee@toot.community yes

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@david@social.kernel.org @vbabka@mastodon.social This is all very naval gazey and I apologise for that, in many ways it's dull and repetitious, but I want to 'talk out loud' about it while it's fresh... The issue underlying it all is that I REALLY truly believe that I'm just not that good. And I'm not sure I can ever get past that. That feeling that underneath it all, people see me as an amusing sideshow of churn and code style commentary is hard to escape, no matter what anybody says (well of course they'd be kind to me, etc. the loop continues, endlessly) Sometimes the demon speaks louder and sometimes softer. I think the only way to deal with it is to ignore it, because in the end if I am stupid and untalented, it's almost immaterial. I chose to do this thing, I have responsibilities in this thing, and stupid or not, skilled or not, respected or not, I am going to keep doing it, whether professionally or as a hobbyist. The only winning game with a demon is not to listen, in other words.

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@wagi@mastodon.social tell me about it ;)

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

WYSIWYG was a terrible idea

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Last workout before Zagreb

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Lorenzo @ljs@mastodonapp.uk

· 3mo ago

Replying to

@lkundrak@metalhead.club wet and in whom's church?

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

Unfortunately I don't think I can publicly push back on AI slop again, at least until people wake up to the reality of the threat.

I am not being backed by the community on a case which is really obvious, so that means I can't push back without the person admitting it going forwards.

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

https://www.youtube.com/watch?v=NBtUgWn-nHs

Also pope Catholic, bears shit in the woods

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@david@social.kernel.org @vbabka@mastodon.social You end up 'stuck' on the things your mind is telling you that are true - others had more insight, better commentary, more rooted in experience. Others spoke with more eloquence, more authority, with fewer words, less umming and ahhing... Others are far better respected, as revealed in the numerous ways people reveal themselves both verbally and otherwise. All true, but not the same thing as 'therefore I am a fraud and worthless'. More like - clearly I lack a broader view of "the mm in action". I'm burnt out and spread thin on review load. AND I CAN FIX THAT. There are insights to be had here - what exactly made other's insights more useful? It was the breadth, observing broken workloads _in practice_, the focus too. All things I can take as signals that point me at ways to improve as a kernel developer and maintainer.

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@david@social.kernel.org @vbabka@mastodon.social I try very hard to not let this 'be a thing' especially at a conference, I hate to drag people down or put my shit on them, but some moments it's all just a bit too much (I have basically every part of my life on fire at once at the moment, with little to no escape). A depressed brain, especially if you have some degree of smarts, is a terrible source of pain. (Relatedly, I promise) the power of the movie 'The Exorcist' is that it's _really_ talking about mental health: "The demon is a liar. He will lie to confuse us; but he will also mix lies with the truth to attack us. His attack is psychological, Damien. And powerful." And that's the problem.

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

Spiderman meme with cats

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

Replying to

@ptesarik@infosec.exchange @vbabka@mastodon.social @monsieuricon@social.kernel.org I absolutely agree

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

Replying to

@vbabka@mastodon.social @monsieuricon@social.kernel.org I mean claude did it so it's not me at all

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

Replying to

@corbet@social.kernel.org I hope so. But I thought what Matthew said was very touching and speaks to the support the community has (and needs to have) for those who are going through this kind of thing.

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@lkundrak@metalhead.club @ptesarik@infosec.exchange brain was a mistake fish don't care

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@lkundrak@metalhead.club @ptesarik@infosec.exchange nah I'm just dumb

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

As usual hit day 3 of lsf and I'm fully exhausted... how do people do this lol

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

My luck lately, I have endless personal life stuff going on and then this AI slop and of course I'm not supported on it because 2026 keeps giving and... like honestly can I have 1 normal week please?

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Lorenzo @ljs@mastodonapp.uk

· 4mo ago

Replying to

@MetalheadDana@metalhead.club bro it's nothing compared to jason's bass tone on and justice

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@vitaut@mastodon.social all 173 lol How is tesla not just a giant stock fraud? (I phrased that carefully for legal reasons)

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@ptesarik@infosec.exchange @lkundrak@metalhead.club yes. Also I am a huge imposter/fraud ofc

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Lorenzo @ljs@mastodonapp.uk

· 5mo ago

Replying to

@bonkers@nerdculture.de shit you found me out!

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Lorenzo @ljs@mastodonapp.uk

· 2mo ago

Replying to

Bedroom is consistently 29-32 degrees overnight... ugh

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