Tech News Digest - 2025-04-07
📢 No joke file found! 😢
Kernel prepatch 6.15-rc1
Category: Linux
Tags: General
Published: Sun, 06 Apr 2025 23:09:46 +0000
TL;DR: Here is a summary of the text in 2 sentences:
Linus Torvalds has released Linux kernel version 6.15-rc1 and closed the merge window for this release, which was slightly larger than usual due to pent-up development following holidays. A total of 12,633 non-merge changesets were pulled into the mainline during this merge window.
Linus has released 6.15-rc1 and closed the
merge window for this release. "As expected, this was one of the bigger
merge windows, almost certainly just because we had some pent-up
development due to the previous releases being impacted by the holiday
season. That said, while it's bigger than normal, it's not some kind of
record-breaking thing.
". In the end, 12.633 non-merge changesets were
pulled into the mainline during this merge window.
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[$] The state of guest_memfd
Category: Linux
Tags: General
Published: Fri, 04 Apr 2025 15:52:32 +0000
TL;DR: Here is a summary of the text in 2 sentences:
In cloud computing, each guest running on a host shares some memory with the host, which can access that memory to gather private data from the guest. The "guest_memfd" subsystem helps remove the host's access to guest memory, making it more secure and private for the guest.
A typical cloud-computing host will share some of its memory with each
guest that it runs. The host retains its access to that memory, though,
meaning that it can readily dig through that memory in search of data that
the guest would prefer to keep private. The guest_memfd subsystem removes (most of) the
host's access to guest memory, making the guest's data more secure. In the
memory-management track of the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit, David Hildenbrand ran a discussion on
the state and future of this feature.
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[$] The future of ZONE_DEVICE
Category: Linux
Tags: Linux
Published: Fri, 04 Apr 2025 14:37:57 +0000
TL;DR: Here is a 2-sentence summary:
Alistair Popple referred to ZONE_DEVICE as the "ugly stepchild" of the kernel's memory-management subsystem at the Linux Storage, Filesystem, Memory-Management, and BPF Summit, acknowledging its importance on current hardware. He aimed to discuss the challenges with ZONE_DEVICE and find ways to improve it, potentially making it more attractive or integrated into the main system.
Alistair Popple started his session at the 2025 Linux Storage, Filesystem,
Memory-Management, and BPF Summit by proclaiming that ZONE_DEVICE
is "the ugly stepchild
" of the kernel's memory-management subsystem.
Ugly or not, the ability to manage memory that is attached to a peripheral
device rather than a CPU is increasingly important on current hardware.
Popple hoped to cover some of the challenges with ZONE_DEVICE and
find ways to make the stepchild a bit more attractive, if not bring it into
the family entirely.
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[$] Supporting untorn buffered writes
Category: Linux
Tags: General
Published: Fri, 04 Apr 2025 13:39:56 +0000
TL;DR: Here is a summary of the text in 2 sentences:
At last year's Linux Storage, Filesystem, Memory-Management, and BPF Summit, there was a discussion about adding atomic write support to the block layer and XFS filesystem. This year, Luis Chamberlain led a track at the summit to revisit the idea of providing atomic writes for buffered I/O, with the goal of simplifying writes in databases like PostgreSQL that currently require special handling to avoid torn writes.
At last year's
Linux Storage, Filesystem,
Memory-Management, and BPF Summit (LSFMM+BPF), there was a discussion about atomic writes that was
accompanied by patches to support the feature in the block layer, and for
direct I/O on XFS. That
work was merged, but another piece of that discussion concerned adding the
feature for buffered I/O, in part because the PostgreSQL database currently
has to jump through hoops to ensure that its writes are not "torn"
(partially written) when there is an error or crash. Luis Chamberlain led
a combined storage and filesystem track at this year's summit to revisit
the idea of providing atomic (or untorn) writes for buffered I/O.
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[$] A strange BPF error message
Category: Linux
Tags: General
Published: Fri, 04 Apr 2025 13:06:07 +0000
TL;DR: Here is a 2-sentence summary:
Yonghong Song presented a talk at the 2025 Linux Storage, Filesystem, Memory-Management, and BPF Summit about tracking down a strange verifier error message and proposed ways to improve Clang's user experience. He also discussed issues with optimizations that change function signatures, building on a previous session by José Marchesi.
Yonghong Song brought a story about tracking down the cause of a strange verifier error
message to the 2025 Linux Storage, Filesystem, Memory-Management, and BPF
Summit. He then presented some possible ways to improve Clang's user experience for
anyone running into the same class of error in the future. Toward the end of his
allotted time, he also discussed the problems with optimizations that change the
signature of functions — a problem that José Marchesi had also brought up in
the previous session.
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