news
LWN on Kernel Space (Linux)
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Famfs, FUSE, and BPF [LWN.net]
The famfs filesystem first showed up on the mailing lists in early 2024; since then, it has been the topic of regular discussions at the Linux Storage, Filesystem, Memory Management and BPF (LSFMM+BPF) Summit. It has also, as result of those discussions, been through some significant changes since that initial posting. So it is not surprising that a suggestion that it needed to be rewritten yet again was not entirely well received. How much more rewriting will actually be needed is unclear, but more discussion appears certain.
Famfs is designed to support large, read-mostly filesystems stored in shared memory. In practice, this means huge data sets kept in CXL-attached memory that is made available to multiple systems simultaneously. In normal usage, software running on those systems will access this data by mapping it directly into its address space with mmap(), so that the data is all immediately accessible without system calls, and without going through the system's page cache. It is possible to perform normal filesystem reads and writes, though write access is only minimally supported.
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On pages and folios [LWN.net]
The kernel coverage here at LWN often touches on memory-management topics and, as a result, tends to talk a lot about both pages and folios. As the folio transition in the kernel has moved forward, it has often become difficult to decide which term to use in writing that is meant to be both approachable and technically correct. As this work continues, it will be increasingly common to use "folio" rather than page. This article is intended to be a convenient reference for readers wanting to differentiate the two terms or understand the state of this transition.
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The rest of the 7.1 merge window [LWN.net]
By the time Linus Torvalds released 7.1-rc1 and closed the 7.1 merge window, 12,996 non-merge changesets had been pulled into the mainline repository; just over 9,000 of those arrived after the first-half summary was written. These changes were more driver-oriented than those seen earlier, but still also included many new features across the kernel as a whole.
Aside from the specific changes, it is worth noting that 2,011 developers contributed changes during the 7.1 merge window; 342 of those developers were first-time contributors to the kernel. The trend of increasing numbers of new developers coming into the community that was described in the development statistics article for 7.0 appears to be continuing.