Introducing NVMe atomic write support with QEMU 9.2
QEMU provides NVMe device emulation, a valuable resource for developers testing drivers, tools, and new OS features. With the release of QEMU 9.2, NVMe emulation now includes support for Controller Atomic Parameters (AWUN and AWUPF), allowing for atomic handling of writes that comply with these parameters. Future updates are expected to enhance NVMe Atomic Write support by adding Namespace Atomic Parameters and Namespace Atomic Boundary Parameters.
This blog post introduces the functionality of Atomic Writes in NVMe controllers and offers guidance on setting up Atomic Writes for a QEMU-NVMe device.
Detecting and debugging zombie memcg issues
In the Linux kernel, when a memory cgroup (memcg) is removed from user space, it transitions to an offline state and becomes invisible to the user, yet the kernel retains internal data structures for this memcg, effectively turning it into a "zombie." Although Linux kernel version 6.12 addresses some issues related to zombie memcgs, it does not resolve those created by pinning from pagecache pages.
This blog post provides guidance for Linux users on how to check for the presence of this issue on a live system or within a kernel core dump (vmcore).
Corelens: a microscope for your vmcores
When critical kernel crashes occur, Oracle Linux Support analyzes vmcores (memory dumps) to diagnose issues. However, these files can be hundreds of gigabytes and take a long time to upload. To address this, Oracle developed Corelens, a tool that extracts key diagnostic information from a vmcore into a much smaller report that can be uploaded immediately. This allows support teams to start troubleshooting sooner, even before the full vmcore is available. Corelens also simplifies the process by working without requiring additional debuginfo packages, though full dumps may still be needed for complex cases.
Additional information are available in the blog post. |
