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Linus has released 6.4-rc3 for testing. "Nothing really huge stands out there".

The PyPI Python module repository has temporarily suspended acceptance of new users and project names.

New user and new project name registration on PyPI is temporarily suspended. The volume of malicious users and malicious projects being created on the index in the past week has outpaced our ability to respond to it in a timely fashion, especially with multiple PyPI administrators on leave.

Memory control groups (or "memcgs") allow an administrator to manage the memory resources given to the processes running on a system. Often, though, memcgs seem to have memory-use problems of their own, and that has made them into a recurring Linux Storage, Filesystem, and Memory-Management Summit topic since at least 2019. The topic returned at the 2023 event with a focus on the handling of shared, anonymous memory. The quirks associated with this memory type, it seems, can subject systems to an unpleasant sort of zombie invasion; a session in the memory-management track led by T.J. Mercier, Yosry Ahmed, and Chris Li discussed possible solutions.

Bernd Schubert led a session at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit on the intersection of FUSE and io_uring. He works for DDN Storage, which is using FUSE for two network-storage products; he has found FUSE to be a bottleneck for those filesystems. That could perhaps be improved by using io_uring, which is something he has been working on and wanted to discuss.

The "scatterlist" is a core-kernel data structure used to describe DMA I/O operations from the point of view of both the CPU and the peripheral device. Over the years, the shortcomings of scatterlists have become more apparent, but there has not been a viable replacement on the horizon. During a memory-management session at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit, Jason Gunthorpe described a possible alternative, known alternatively as "phyr", "physr", or "rlist", that might improve on scatterlists for at least some use cases.

Memory management is tricky enough on it own, but virtualization adds another twist: now there are two kernels (host and guest) managing the same memory. This duplicated effort can be wasteful if not implemented carefully, so it is not surprising that a lot of effort, from both hardware and software developers, has gone into this problem. As Pasha Tatashin pointed out during a memory-management-track session at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit, though, there are still ways in which these systems run less efficiently than they could. He has put some effort into improving that situation.

Security updates have been issued by Fedora (cups-filters, kitty, mingw-LibRaw, nispor, rust-ybaas, and rust-yubibomb), Mageia (kernel-linus), Red Hat (jenkins and jenkins-2-plugins), SUSE (openvswitch and ucode-intel), and Ubuntu (linux-azure, linux-azure-4.15, linux-gcp, linux-gcp-5.15, linux-gke, linux-gke-5.15, linux-gkeop, linux-oracle-5.15, linux-ibm, linux-oracle, and linux-oem-6.0).

Joel Fernandes introduced himself to the memory-management track at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit as a co-maintainer of the read-copy-update (RCU) subsystem and an implementer of the "lazy RCU" functionality. Lazy RCU can improve performance, especially on systems that are not heavily utilized, but it also has some implications for memory management that he wanted to discuss with the group.

The memory-management subsystem has the unenviable task of trying to predict which pages of memory will be needed in the near future. Since predictions tend to be difficult, the code relies heavily on the heuristic that memory used in the recent past is likely to be used again in the near future. However, even knowing which memory has been recently used can be a challenge. At the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit, Aneesh Kumar and Wei Xu, both presenting remotely, discussed some ways to use the increasingly capable hardware counters that are provided by current and upcoming CPUs.

The buffer head is a kernel data structure that dates back to the first Linux release; for much of the time since then, kernel developers have been hoping to get rid of it. Hannes Reinecke started a plenary session at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit by saying that everybody agrees that buffer heads are a bad idea, but there is less agreement on how to take them out of the kernel. The core functionality they provide — facilitating sector-size I/O operations to a block device underlying a filesystem — must be provided somehow.

Security updates have been issued by Debian (chromium and libapache2-mod-auth-openidc), Fedora (clevis-pin-tpm2, greetd, keyring-ima-signer, libkrun, mirrorlist-server, nispor, nmstate, qt5-qtbase, rust-afterburn, rust-below, rust-bodhi-cli, rust-cargo-c, rust-coreos-installer, rust-fedora-update-feedback, rust-git-delta, rust-gst-plugin-reqwest, rust-pore, rust-rpm-sequoia, rust-sequoia-octopus-librnp, rust-sequoia-policy-config, rust-sequoia-sq, rust-sevctl, rust-tealdeer, and rust-ybaas), Oracle (apr-util, curl, emacs, firefox, kernel, libreswan, mysql, nodejs and nodejs-nodemon, openssh, thunderbird, and webkit2gtk3), Red Hat (apr-util, emacs, firefox, git, jenkins and jenkins-2-plugins, kernel, kpatch-patch, and thunderbird), Scientific Linux (apr-util, firefox, and thunderbird), Slackware (curl), SUSE (cups-filters, curl, java-1_8_0-openjdk, kernel, mysql-connector-java, and ovmf), and Ubuntu (cups-filters, git, linux-gcp-4.15, linux-oracle, linux-raspi, node-minimatch, ruby2.3, ruby2.5, ruby2.7, and runc).

The LWN.net Weekly Edition for May 18, 2023 is available.

When OpenAI made its chatbot ChatGPT available to the public in November 2022, it immediately became a hit. However, despite the company's name, the underlying algorithm isn't open. Furthermore, ChatGPT users require a connection to OpenAI's cloud service and face usage restrictions. In the meantime, several open-source or freely available alternatives have emerged, with some even able to run on consumer hardware. Although they can't match ChatGPT's performance yet, rapid advancements are occurring in this field, to the extent that some people at the companies developing these artificial intelligence (AI) models have begun to worry.

Version 2.39 of the util-linux tool collection has been released. The most significant change, perhaps, is support for the new filesystem-mounting API, which enables a number of new features, including ID-mapped mounts.

There are some filesystems that use the Filesystem in Userspace (FUSE) framework but only to provide a different view of an underlying filesystem, such as different file metadata, a changed directory hierarchy, or other changes of that sort. The read-only filtered filesystem, which simply filters the view of which files are available, is one example; the file data could come directly from the underlying filesystem, but currently needs to traverse the FUSE user-space server process. Finding a way to bypass the server, so that the file I/O operations go directly from the application to the underlying filesystem would be beneficial. In a filesystem session at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit, Miklos Szeredi wanted to explore different options for adding such a mechanism, which was referred to as a "FUSE passthrough"—though "bypass" might be a better alternative.

The conversion of the kernel's memory-management subsystem over to folios was never going to be done in a day. At a plenary session at the start of the second day of the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit, Matthew Wilcox discussed the current state and future direction of this work. Quite a lot of progress has been made — and a lot of work remains to be done.

The Debian Technical Committee has announced a new moratorium on moving files from the root into /usr, a necessary part of its UsrMerge project. Many distributions have made this change, but Debian has had more difficulties than most; LWN last looked at this project one year ago.

This moratorium lasts until we vote to repeal it. We expect to do that during the trixie development cycle, and sooner rather than later. We will continue to facilitate efforts to resolve the remaining issues that stand in the way of safely repealing the moratorium.

Trixie is the codename for Debian 13, the upcoming major release cycle.

A new development in the NVMe world was the subject of a combined storage and filesystem session led by Stephen Bates at the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit. Computational storage namespaces will allow NVMe devices to offer various types of computation—anything from simple compression through complex queries and data manipulations—to be performed on the data stored on the device.

The use of huge pages can make memory management more efficient in a number of ways, but it can also impose costs in the form of internal fragmentation and I/O amplification. At the 2023 Linux Storage, Filesystem, Memory-Management and BPF Summit, James Houghton ran a session on a scheme to get the best of both worlds: using huge pages while maintaining base-page mappings within them.

The 6.3.3, 6.2.16, 6.1.29, 5.15.112, 5.10.180, 5.4.243, 4.19.283, and 4.14.315 stable kernels have all been released; each contains another set of important fixes. Note that 6.2.16 will be the final update for the 6.2 kernel.