Kernel and Kubernetes

posted by Roy Schestowitz on Apr 27, 2023

• Process-level kernel samepage merging control

  The kernel samepage merging (KSM) feature can save significant amounts of memory with some types of workloads, but security concerns have greatly limited its use. Even when KSM can be safely enabled, though, the control interface provided by the kernel makes it unlikely that KSM actually will be used. A small patch series from Stefan Roesch aims to change this situation by improving and simplifying how KSM is managed.

  As its name would suggest, KSM works by finding pages of memory with identical contents and merging them into a single copy that is shared by all users. An early use case, as described by Avi Kivity in 2008 when the feature was first proposed, was ""the typical multiuser gnome minicomputer with all 150 users reading lwn.net at the same time instead of working""; this workload would generate a lot of identical cache pages that could be shared rather than duplicated across the system. There are other use cases, such as virtual machines or containers running the same software, that could also be optimized once the important workloads have been addressed.

• Avoiding the merge trap

  The kernel subsystem maintainers out there probably have a deep understanding of the sinking feeling that results from opening one's inbox and seeing a response from Linus Torvalds to a pull request. When all goes well, pull requests are acted upon silently; a response usually means that all has not gone well. Several maintainers got to experience that feeling during the 6.3 merge window, which seemed to generate more than the usual number of grumpy responses related to merge commits. Avoiding that situation is not hard, though, with a bit of attention paid to how merges are done.

  When using a distributed system like Git, development is done in numerous parallel tracks, each of which has its own starting point. Even if a particular project starts at the tip of the mainline tree, the mainline itself is almost certain to have moved on by the time that work is ready to land there. Bringing independent lines of development back together is called "merging"; depending on what has changed, any given merge can be simple or a nasty mess of conflicting changes.

• [ANNOUNCE] weston 11.0.91

  Hi all,

  This is the alpha release for Weston 12.0.0.

• Kubernetes v1.27 Update Brings Chill Vibes

  Kubernetes v1.27, the first K8s release of 2023, has been announced. The v1.27 release includes 60 enhancements, 18 of which are alpha, 29 are beta and 13 are stable at the time of writing. Due to a surprisingly easy release process, the maintainers have coined v1.27 the Chill Vibes release.