Category Archives: Linux

Linux’s Kconfig Is No Longer Orphaned

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Back in August, open-source developer Masahiro Yamada stepped down from maintaining the Kconfig and Kbuild areas of the Linux kernel. While Kbuild maintainership was quickly passed on, no one immediately stepped up to maintain Kconfig as the infrastructure code for configuring the Linux kernel builds. That led to Kconfig officially being orphaned code within the kernel but now that situation has been addressed…

Summary of the Amazon DynamoDB Service Disruption in Northern Virginia (US-EAST-1) Region

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We apologize for the impact this event caused our customers. While we have a strong track record of operating our services with the highest levels of availability, we know how critical our services are to our customers, their applications and end users, and their businesses. We know this event impacted many customers in significant ways. We will do everything we can to learn from this event and use it to improve our availability even further.

VMScape: Cracking VM-Host Isolation in the Speculative Execution Age & How Linux Patches Respond

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In the world of modern CPUs, speculative execution, where a processor guesses ahead on branches and executes instructions before the actual code path is confirmed, has long been recognized as a performance booster. However, it has also given rise to a class of vulnerabilities collectively known as “Spectre” attacks, where microarchitectural side states (such as the branch target buffer, caches, or predictor state) are mis-exploited to leak sensitive data.

[$] Safer speculation-free user-space access

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The Spectre class of hardware vulnerabilities truly is a gift that keeps on
giving. New variants are still being discovered in current CPUs nearly
eight years after the disclosure of this
problem, and developers are still working to minimize the performance costs
that come from defending against it. The masked user-space access
mechanism is a case in point: it reduces the cost of defending against some
speculative attacks, but it brought some challenges of its own that are
only now being addressed.

Linux’s Proposed Cache Aware Scheduling Benchmarks Show Big Potential On AMD EPYC Turin

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The past number of months has seen a lot of work by Intel Linux kernel engineers on cache-aware scheduling / load balancing for helping modern CPUs that have multiple caches. With cache aware scheduling, tasks that will likely share resources could be aggregated into the same cache domain to enjoy better cache locality. With the cache aware scheduling patches recently updated and now working past the “request for comments” stage, I was eager to try out these new patches. Especially with a 44% time reduction reported for one of the benchmarks, I was eager to run some tests and the first of those results are being shared today.

Btrfs support coming to AlmaLinux 10.1

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The AlmaLinux project has announced
that the upcoming 10.1 release will include support for
Btrfs:

Btrfs support encompasses both kernel and userspace enablement, and
it is now possible to install AlmaLinux OS with a Btrfs filesystem
from the very beginning. Initial enablement was scoped to the
installer and storage management stack, and broader support within the
AlmaLinux software collection for Btrfs features is forthcoming.

Btrfs support in AlmaLinux OS did not happen in isolation. This was
proposed and scoped in RFC 0005, and has been built upon prior efforts
by the Fedora
Btrfs SIG in Fedora Linux and the CentOS Hyperscale SIG
in CentOS Stream.

AlmaLinux OS is designed to be binary compatible with Red Hat
Enterprise Linux (RHEL); Btrfs, however, has never been supported in
RHEL. A technology preview of Btrfs in RHEL 6 and 7 ended with the
filesystem being dropped from RHEL 8 and
onward. AlmaLinux OS 10.1 is currently
in beta.