Kernel News and LWN's Latest
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Security Boulevard ☛ Rust vs. C — Linux’s Uncivil War [Ed: Linux-hostile and Microsoft-connected sites try to push in the dagger using Rust]
The big debate over using Rust in the Linux kernel continues. After one of Linus Torvalds’ ALL CAPS interventions last week, kernel 2IC Greg Kroah-Hartman wades in with a please-and-thank-you follow-up.
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LWN ☛ Extending time slices for user-space locks
Steven Rostedt recently posted a patch set that could help improve the performance of certain user-space applications by giving the scheduler more context about when they are safe to interrupt. The patch set lets programs request a small grace window before they can be interrupted so that they can relinquish any locks, decreasing the amount of time that other threads have to spend waiting. Rostedt shared performance numbers suggesting that the patch might cut the amount of time spent acquiring locks in half for some programs — although, since his test was specifically tuned for this case, real-world projects should expect a somewhat less dramatic improvement. The change received some pushback from scheduler maintainer Peter Zijlstra, who objected to the patch set's approach.
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LWN ☛ Multi-size THP creation, two different ways
Huge pages can increase the performance of many programs, but they can also have unfortunate performance impacts of their own. Over the last few years, multi-size transparent huge pages (mTHPs) have increasingly been seen as a happy medium that bring the benefits of huge pages at a lower cost. The system cannot benefit from mTHPs, though, if it does not create them; two developers have independently posted patches to enable the creation of mTHPs in the background.
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LWN ☛ The evolution of Memcached
Memcached is a memory-based data-caching daemon that has a long history. More than twenty years after its first public release, Memcached strives to remain relevant in a vastly changed computing landscape, balancing new features with a commitment to the original principles that separate it from newer alternatives like Redis and Hazelcast.
Memcached was launched in 2003 by Brad Fitzpatrick, who designed the project to help LiveJournal serve blogs at scale. BSD-licensed and written primarily in C, Memcached was built for a world of computing resources that were—from a 2025 perspective—scarce, expensive, and slow to set up. Memcached offered developers of high-demand web applications a clever way to run a large shared cache of frequently accessed data, using the spare memory of whatever servers happened to be available to them.
Today, development of Memcached continues on GitHub and it is now primarily maintained by the pseudonymous Dormando, who has maintained the project since 2007. He runs a consulting company, Cache Forge, that provides support for Memcached. The project made more than a dozen releases in 2024, the most recent of which is 1.6.34, from December. Dormando is, by far, the most active committer in the past year or so. The rest of the commits have come from nine contributors with just one or two commits each. The more recent releases of Memcached aim to preserve its utility in a world of faster, cheaper servers—ones more likely to be cloud-based and intentionally ephemeral.
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LWN ☛ Meshtastic: decentralized communication with low-power devices
Many of us enjoy uninterrupted access to mobile networks. However, in remote areas or during emergencies, that connectivity may not always be available. For such scenarios, Meshtastic offers a decentralized wireless mesh network with open-source firmware that runs on affordable, low-power devices. At FOSDEM 2025, the Meshtastic project was represented by one of its core developers, Thomas Göttgens, who gave a talk, "Meshtastic - off-grid communication for everyone", in the Radio developer room (devroom).
In the introduction, the devroom organizer made the disclaimer that Meshtastic relies on proprietary and patented technology, referring to the LoRa communication technology developed by Semtech. ""But it is cool"", he added. Göttgens then started his talk by emphasizing that the project is fully open source, except for the radio chips that use the proprietary and patented technology.