Linux Bugs

Hypocrite Commits, Rust RFC, and FUTEX2 were some popular kernel topics in 2021

There have been a ton of exciting kernel improvements merged in 2021, along with the introduction of new hardware support and more. But as exciting as the year has been, it has actually been weaker than usual in terms of commits and row counts. Here’s a look at some of the popular core topics in 2021 as well as a look at Git’s annual development statistics.

Yesterday while running GitStats on the Linux kernel source tree, the repository saw 1,060,172 commits from about 24.3,000 different authors. The source tree currently has 32.2 million lines out of 74.3,000 files.

The linux kernel line count continues to grow at a fairly constant rate overall with the endless stream of new features and extensive hardware support reaching the mainline.

While for 2021 with features and hardware support, the kernel only saw 73.7k commits in 2021 – up from 90.2k in 2020, 82.8k in 2019, 80.1k in 2018, etc. The last time there were 73k or less commits in a single year was in 2013 when it hit 70.9,000. Although partly for the lag is that in 2021 there were 5 releases major kernel releases as some years saw 6 major releases and in turn the extra merge window during that calendar year which leads to the great flow of new commits … Linux 5.16 is coming out in a few weeks, this will in turn launch the Linux 5.17 merge window in January.

In addition to significantly fewer commits than usual, in 2021 the Linux kernel saw 3.2 million lines added and 1.3 million lines deleted, less than in 2020 which saw 4 million lines added with 1.5 million rows deleted.

Linus Torvalds has been the most prolific contributor to the source tree, as usual. The next five top contributors to the Linux kernel source tree were longtime prominent kernel contributors David S. Miller, Arnd Bergmann, Christoph Hellwig, Lee Jones, and Jakub Kicinski.

In 2021, there were 4,421 different emails associated with Linux kernel commits, down from 4,603 seen in 2020 but up from 2019 at 4,383.

Those curious about the full Linux kernel GitStats for 2021 and prior years can view this dump with all the details.

Recapping the cool features, proposed changes, and other core drama of 2021, the most popular core Phoronix posts for the year included:

University was banned from contributing Linux kernel for intentionally inserting bugs
Greg Kroah-Hartman has banned an American university from trying to patch the Linux kernel instead of intentionally submitting questionable code with security implications and other “experiments” in the name of research.

Linus Torvalds decides to support NVIDIA RTX 30 “Amps” in Linux 5.11
While new feature code is not normally allowed after the merge window ends for a given Linux kernel release cycle, Linus Torvalds has decided to merge the newly released open source driver code for NVIDIA graphics cards. GeForce RTX 30 “Ampere”. for the Linux 5.11 kernel which will debut as stable in February.

IBM To Kernel Maintainer: “You are an IBM employee 100% of the time”
It is quite common for many longtime Linux kernel developers to use their personal email addresses to sign kernel patches or deal with other patch work, especially when they are also engaging in kernel development. during their personal time and occasionally jump between employers over time while remaining steadfast in interacting with the upstream core community, etc. There are also, of course, some companies that are enforcing the use of their corporate email addresses for their official work / fixes, while IBM now seems to be going to the extreme.

Linux 5.13 rolls back + fixes problematic University of Minnesota fixes
A month ago, the University of Minnesota was banned from contributing to the Linux kernel when it was revealed that university researchers were intentionally attempting to submit bugs in the kernel via new fixes as “hypocritical commissions” in part of a questionable research paper. Linux kernel developers have finally finished reviewing all UMN.edu patches to resolve kernel merge issues and also clean up / repair their questionable patches.

Btrfs will finally “strongly discourage” you when creating RAID5 / RAID6 arrays
For a number of years it has been known that the Btrfs RAID5 and RAID6 code is potentially dangerous and not as mature as the native RAID support found in this Linux file system for other levels. Finally, we now see that the Btrfs user space programs warn the user when they attempt to create such native Btrfs RAID 5/6 configurations.

Linux kernel developers discuss removing a bunch of old processors
Since Linux 5.10 is the last version of Long Term Support (LTS) to be maintained for at least the next five years, a discussion has started on removing a number of old and obsolete CPU platform support currently found in the main core. For most architectures being considered for deletion, they have not seen any new commits in years, but as is the case once proposals are made for their deletion, there are often passionate users who wish that the support is retained.

It turns out that Windows unconditionally reserves the first 1MB of RAM, Linux was just late in doing it
The change was sent last weekend to Linux kernel 5.13, so Linux x86 / x86_64 will always reserve the first 1MB of RAM to avoid corruption issues with some BIOS and image buffers sometimes playing with the lowest part of system memory. While the idea was that the first 1MB unconditionally was a bit on the expensive side, and Windows might have a way of figuring out how much low memory to reserve, it turns out that Windows has been using this same behavior for years.

Axboe Achieves 8 Million IOPS Per Core With Latest Linux Optimization Patches
It wasn’t until last week that Linux optimizations led to 6 million IOPS per core, and then earlier this week new fixes pushed Linux past 7 million IOPS per core with a hardware configuration. also ideal. At the end of the week, 8M IOPS were reached!

“le9” strives to make Linux very usable on systems with small amounts of RAM
It is well known that the Linux desktop can be quite unbearable when under high memory pressure as has been demonstrated over the years and more and more attention these days is turning to OOMD / systemd-oomd and other alternatives to better handle Linux low / out-low memory scenarios, especially with today’s desktop software and web browsers consuming increasing amounts of memory. The Linux kernel “le9” patches are another effort that is coming to fruition to help this scenario.

Linux x86 / x86_64 will now always reserve the first 1MB of RAM
The Linux x86 / x86_64 kernel code already had logic in place to reserve portions of the first 1MB of RAM to prevent the BIOS or kernel from potentially overwriting that space, among other reasons, while now Linux 5.13 remove this “disguise” and will do so unconditionally. always reserve the first 1MB of RAM.

University of Minnesota “Hypocrite Commit” Linux Researchers Publish Open Letter
The drama in Kernel Country this week has been the University of Minnesota’s ban on Linux kernel development because of its previous research into “hypocritical engagements” and the possibility of intentionally introducing vulnerabilities ( such as usage bugs after free use) in the kernel source. tree. This weekend, the researchers involved published an open letter to the Linux kernel community.

Linux 5.16 will be a great Christmas present for free software fans with many new features
While Linux 5.15 won’t even debut for a week or two, there is already a lot to look forward to when it comes to Linux 5.16. Here’s a look at some of the new features expected for the 5.16 cycle.

Linux 5.17 to boast of great TCP performance optimization
While the Linux 5.16 merge window has just ended and this kernel will not be released until the end of the calendar year, already for Linux 5.17, new hardware is starting to pile up in the development trees of sub. respective systems … A set of changes merged this morning from Google can provide a huge performance boost around TCP performance in the data center.

New NTFS file system driver has been submitted for Linux 5.15
It looks like Paragon Software’s NTFS3 kernel driver with much better Linux support for the Microsoft NTFS file system will be coming to the 5.15 kernel!

Linux Achieves 5.1 Million IOPS Per Core With AMD Zen 3 + Intel Optane
The Linux kernel developers have worked tirelessly to optimize the performance of IO_uring and block / I / O code in general. Senior IO_uring developer Jens Axboe, who also serves as maintainer of the Linux block subsystem (among other roles and major contributions over the years) used his system as a benchmark to evaluate such kernel enhancements. It has now switched to using AMD Zen 3 while sticking to Intel Optane storage and sees a powerful increase in speed from AMD’s latest processors.

Samsung 860/870 SSDs Continue to Cause Problems for Linux Users
While Samsung has explicitly stated before that Queued TRIM works for Samsung 860 SSDs in Linux and only older Samsung 840/850 drives are blocked from using Queued TRIM, it turns out. inaccurate and now more quirks are added for the Samsung 860 and 870 series SSDs in Linux.

Linux 5.13 released with Apple M1 Bringup, Landlock, FreeSync HDMI and more
Linus Torvalds has just released Linux kernel 5.13 as stable.

Facebook worked on bolting the Linux kernel for better performance
For several years, Facebook engineers have been working on BOLT as a way to speed up Linux / ELF binaries. This “binary optimization and layout tool” is able to rearrange executables once profiled to generate even faster performance than can be achieved by LTO and PGO optimizations of a compiler. One of BOLT’s last efforts was to optimize the Linux kernel image.

Rust code update for released Linux kernel patches
In 2022, we will most likely see support for the experimental programming language Rust in the built-in Linux kernel. The updated fixes that introduced the initial support and infrastructure around managing Rust in the kernel were sent this morning.

It looks like FUTEX2 will land for Linux 5.16
Unless last minute reservations, it seems that the initial “FUTEX2” work which is of great interest to Linux gamers enjoying Steam Play / Proton will find this kernel functionality in Linux 5.16.


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