[$] Atomic writes for ext4

Building on the discussion in the two previous sessions on untorn (or
atomic) writes, for buffered I/O and for XFS using direct I/O, Ojaswin Mujoo
remotely led a
session on support for the feature on ext4. That took place in the combined storage and
filesystem track at the
2025 Linux Storage, Filesystem, Memory Management, and BPF Summit. Part of
the support for the feature is already in the upstream kernel, with more
coming. But
there are still some challenges that Mujoo wanted to discuss.

Malcolm: 6 usability improvements in GCC 15

Over on the Red Hat Developer site, David Malcolm has an article
about improvements in GCC 15
, specifically focusing on the diagnostic
information that the compiler emits. This includes ASCII art with a “⚠️”
warning emoji to display the execution path when it detects a problem (like
an infinite loop in one of his examples), better C++ template errors,
machine-readable diagnostics using Static
Analysis Results Interchange Format
(SARIF), better messages regarding
C23 compatibility since that is the default C version for GCC 15, and more.
Since the changes are focused on messages, there is the inevitable color
scheme update as well:

GCC will use color when emitting its text messages on stderr at a suitably modern terminal, using a few colors that seem to work well in a number of different terminal themes—but the exact rules for choosing which color to use for each aspect of the output have been rather arbitrary.

For GCC 15, I’ve gone through C and C++’s errors, looking for places where two different things in the source are being contrasted, such as type mismatches. These diagnostics now use color to visually highlight and distinguish the differences.

Mesa 25.1 Merges Support For Intel EU Stall Sampling As New Xe2 Profiling Feature

Merged to the Intel Xe kernel graphics driver for the current Linux 6.15 kernel cycle is EU Stall Sampling support as a new feature found with Xe2 Lunar Lake and Battlemage graphics. EU Stall Sampling is used for exposing information/reasons why execution units are stalled for helping to debug performance issues. Now that the kernel support is ready to go with Linux 6.15, merged to the Mesa 25.1 development code is the user-space support for this performance debugging feature…

[$] Management of volatile CXL devices

Compute
Express Link (CXL)
memory is not like the ordinary RAM that one might
install into a computer; it can come and go at any time and is often not
present when the kernel is booting. That complicates the management of
this memory. During the memory-management track of the 2025 Linux Storage,
Filesystem, Memory-Management, and BPF Summit, Gregory Price ran a session
on the challenges posed by CXL and how they might be addressed.

AMD Ryzen AI 7 PRO 360 Linux Performance With The Lenovo ThinkPad T14s Gen 6

For those that are curious about the Linux support and performance of the AMD Ryzen AI 7 PRO 360 laptop processor, I’ve recently been testing it out within a Lenovo ThinkPad T14s Gen 6 (AMD) laptop. Up today are benchmarks of the Ryzen AI 7 PRO 360 within the ThinkPad T14s Gen 6 up against an assortment of other recent Intel and AMD laptops all while running the near-final state of Ubuntu 25.04.

AMD Preferred Core Support For Linux Revised To Better Handle Dynamic Rankings

Merged back in Linux 6.9 was AMD Preferred Core support for Linux for the concept of “preferred cores” with newer Zen processors that are communicated via ACPI CPPC for select cores able to reach a higher maximum frequency or should otherwise be preferred over other cores on the system in the name of maximizing performance. That was a nice step forward for better handling newer Ryzen processors on Linux and matching functionality that had already been working under Microsoft Windows. Of focus more recently has been working on enabling more dynamic Preferred Core support for where the priority of the preferred cores may change at run-time…

Linux Tightening Up AMD Zen 5 CPU Microcode Check

Google engineers earlier this year detailed an AMD CPU microcode signature verification vulnerability. For local users with administration/root privileges, it could lead to loading malicious CPU microcode patches on the system. Initially AMD Zen 1 through Zen 4 were affected but the Google security engineers since discovered Zen 5 also could be impacted. BIOS updates are rolling out to address this signature verification issue while the Linux kernel is also being patched for microcode protections on Zen 5…

Intel Linux Graphics Driver Will Now Be Less Restrictive Over RAM Use

A change merged yesterday to the Intel Mesa graphics driver code lessens a restriction around the amount of system memory (RAM) that can be used by processes for the Vulkan system heap. This will allow more games/apps to work with the Intel integrated graphics that previously exceeded the driver-enforced limits but at the risk of running into broader out-of-memory behavior if under too much memory pressure…