Linux 5.15

It's been calm, and I have no excuse to add an extra rc, so here we
are, with v5.15 pushed out, and the merge window starting tomorrow.

Which is going to be a bit inconvenient for me, since I also have some
conference travel coming up. But it's only a couple of days and I'll
have my laptop with me. Sometimes the release timing works out, and
sometimes it doesn't..

Anyway, the last week of 5.15 was mainly networking and gpu fixes,
with some random sprinkling of other things (a few btrfs reverts, some
kvm updates, minor other fixes here and there - a few architecture
fixes, couple of tracing, small driver fixes etc). Full shortlog
appended.

This release may have started out with some -Werror pain, but it
calmed down fairly quickly and on the whole 5.15 was fair small and
calm. Let's hope for more of the same - without Werror issues this
time - for the upcoming merge window.

                 Linus

The 5.15 kernel has been released

The code name for this release has been set to "Trick or Treat".

Significant features in this release include: the realtime preemption locking code, descriptorless files for io_uring, BPF timers, the removal of mandatory file-locking support, the ksmbd SMB filesystem server (but see this article), printk() indexing, the process_mrelease() system call, The DAMON memory-management optimization system, the ntfs3 filesystem implementation, and much more. See the KernelNewbies 5.15 page for more information.

The 15 Most Interesting Linux 5.15 Kernel Features From NTFS3 To KSMBD & DAMON

Back in September at the end of the Linux 5.15 merge window was our Linux 5.15 feature overview but given the time since then and that the Linux 5.15 stable kernel will likely be released this evening, here is a recap of the most interesting changes in this new kernel version.

Linux 5.15 will be released by tonight unless Linus Torvalds decides to be conservative with an additional release candidate, which would push the final release back to next Sunday. In any case, here is a look at the most interesting changes and new features from our perspective with this next kernel...

Linux 5.15 Released With Initial Intel DG2/Alchemist + Xe HPG Code, New NTFS Driver

Linus Torvalds went ahead and released Linux 5.15 today on Halloween rather than delaying the kernel for another week.

Linux 5.15 has many prominent changes including the introduction of DAMON, the new NTFS file-system driver, initial Xe HPG and DG2/Alchemist support code, Zen 3 APU temperature monitoring, and much more.

Linux 5.15 Released, This is What’s New

What better way to kickstart a brand new month than with a brand new Linux kernel.

Yes, Linux 5.15 is now officially released.

Announcing the new kernel’s arrival on the Linux Kernel mailing list Linux founder Linus Trovalds [sic] writes:

“The last week of 5.15 was mainly networking and gpu fixes, with some random sprinkling of other things (a few btrfs reverts, some kvm updates, minor other fixes here and there – a few architecture fixes, couple of tracing, small driver fixes etc)”, adding that “…on the whole 5.15 was fair small and calm (sic)”.

Linux Kernel 5.15 released, futex2 work to help Linux gaming going into Kernel 5.16 | GamingOnLinux

For the futex2 work coming from Collabora developer André Almeida, another developer Thomas Gleixner has sent in a request for Linus Torvalds to have it included along with other work so we should see it in the next Kernel release. This is for the new system call sys_futex_waitv that will help Linux gaming.

As Almeida previously described it: "The use case of this syscall is to allow low level locking libraries to wait for multiple locks at the same time. This is specially useful for emulating Windows' WaitForMultipleObjects. A futex_waitv()-based solution has been used for some time at Proton's Wine (a compatibility layer to run Windows games on Linux). Compared to a solution that uses eventfd(), futex was able to reduce CPU utilization for games, and even increase frames per second for some games. This happens because eventfd doesn't scale very well for a huge number of read, write and poll calls compared to futex. Native game engines will benefit of this as well, given that this wait pattern is common for games.".

FUTEX2's sys_futex_waitv() Sent In For Linux 5.16 To Help Linux Gaming

As expected after first reporting on it a month ago when the FUTEX2 patches were queued up in locking/core, this work with the new sys_futex_waitv() system call for helping the Windows on Linux gaming experience will indeed land for Linux 5.16.

The FUTEX2 work has been a long time coming and landing for Linux 5.16 is the main part: the sys_futex_waitv system call that allows for waiting on multiple futexes. This is very useful for the likes of Wine and Proton (Steam Play) for better matching the behavior of Microsoft Windows' WaitForMultipleObjects functionality. Making use of this new system call on Linux 5.16+ when patches land for Wine / Proton will allow for greater performance possibilities. Native Linux games may also make use of this system call directly or via a wrapper (e.g. glibc patches have been floated) as well for performance/efficiency benefits. The performance advantage may be in the ballpark of a few percent.

Linux 5.15 Kernel Released - LinuxStoney

After two months of development, Linus Torvalds has released the Linux 5.15 kernel . Notable changes include: new NTFS driver with write support, ksmbd module with SMB server implementation, DAMON subsystem for monitoring memory access, locking primitives for real-time mode, fs-verity support in Btrfs, process_mrelease system call for shortage response systems memory, remote attestation module dm-ima.

The new version received 13,499 fixes from 1888 developers, the size of the patch is 42 MB (changes affected 10,895 files, 632,522 lines of code added, 299,966 lines removed). About 45% of all changes introduced in 5.15 are related to device drivers, approximately 14% of changes are related to updating code specific to hardware architectures, 14% are related to the network stack, 6% are related to filesystems, and 3% are related to internal kernel subsystems.

Linux Kernel 5.15 LTS Released! Brings Improved NTFS Driver to Linux - It's FOSS News

On Halloween, Linus Torvalds announced the availability of the next mainline, Linux Kernel 5.15.

While Linux Kernel 5.14 focused on improvements for ARM-based systems, the focus seems to be on some significant changes this time.

Here, I shall highlight the key highlights of this release.

Linux gets its latest LTS kernel

Linus Torvalds, the principal developer of the mainline Linux branch, released version 5.15 of the open source kernel over the Halloween weekend, and it has just been tagged as the next Long Term Support (LTS) release.

The kernel designates one release every year as an LTS release, which the developers and the community commit to maintain for at least two years.

By this logic, Linux 5.15 will not reach end-of-life before October 2023. However, of late, the kernel has adopted a policy of supporting LTS releases for as long as its commercial users are willing to put up the required resources to maintain it.

Linux Kernel 5.15 is Out! Here’s How to Install in Ubuntu

Linux 5.15 was released yesterday as the new Long Term Support (LTS) kernel release. Here’s what’s new and how to install in Ubuntu.

Linus Torvalds announced the release of Kernel 5.15 on Sunday...

Linux 5.15 Is This Year's LTS Kernel - Phoronix

As we approach the end of the calendar year there was some uncertainty whether Linux 5.15 would be this year's Long-Term Support (LTS) kernel or if it would be Linux 5.16 albeit not likely releasing until the start of 2022...

Well, Greg Kroah-Hartman has decided on Linux 5.15 being the LTS kernel for 2021. The Kernel.org release page has been updated to reflect the newly-released Linux 5.15 kernel being an LTS branch.

At the moment the LTS period projects Linux 5.15 LTS to be end-of-life in October 2023. However, as is usually the case, this can be extended by years given enough industry support. If enough users/developers and organizations step up for committing to testing the new point releases and actually using the LTS kernel in production, the LTS period can be extended by several years.

Linux 5.15 with a fresh NTFS driver and SMB server - Market Research Telecast [Ed: Automated translation]

During the night from Sunday to Monday, Linus Torvalds released version 5.15 of the Linux kernel. The new version is not just a maintenance release, but brings with it new features. The release offers a huge plus in the form of a new NTFS driver, especially for cross-platform data exchange with other systems. Other important innovations: Samba in the kernel and optimizations in the area of ​​the file systems. In the following, we take a brief look at the highlights mentioned in Linux 5.15.

Linux Kernel 5.15 Released, Here Are the Top 3 New Features

Linus Torvalds has announced the release of kernel 5.15. The release offers a huge plus in the form of a new NTFS driver, especially for cross-platform data exchange with other systems.

Above all, Linux Kernel 5.15 is a significant milestone in that it’s also a Long Term Support (LTS) kernel to be maintained for at least the next five years and also is a huge kernel update in general with many new features.

Linux 5.15 LTS release – Main Changes, Arm, RISC-V and MIPS architectures

Released around two months ago, Linux 5.14 added support for Raspberry Pi 400 keyboard computer, merged the core scheduling functionality, removed the old IDE block drivers, improved support for Intel Alder Lake processors, and more.

Linux 5.15 will be an LTS kernel getting long-term support for at least 2 years, and possibly more, if companies extensively use the new kernel and request a longer support period up to 6 years like for Linux 5.10 or Linux 5.4 for instance.

Linux 5.15 just arrived - and here's what's inside [Ed: In its coverage of a Linux relase ZDNet filled the first two paragraphs with Microsoft propaganda, basically painting "Linux" using Microsoft's brush; it's so gross.]

Linux 5.15 also addressed the introduction of -Werror — a move endorsed by Torvalds to force developers to fix bugs earlier. It was intended to be a new default behavior for kernel builds that treated all compiler and configuration "warnings" as "errors" that must be fixed. -Werror however was met with opposition from kernel developers and led to Torvalds partially backtracking on the effort.

Linux 5.15 kernel released with new NTFS driver: next LTS or will 5.16 sneak in? [Ed: When Microsoft Tim covers a Linux release he makes it all about Microsoft]

Linux kernel 5.15 is available, and it has something special for NTFS users

The latest Linux kernel has been released and it has plenty to offer users and admins alike. But this particular release will be particularly pleasing to those who use Linux as either a file-sharing server or a device that must connect to and use NTFS-partitioned drives. On top of these headline changes, there are other new additions and improvements to be found.

[...]

In a word, no. Your best bet is to wait until the kernel is made available via your Linux distribution of choice. Although you can download and compile the latest kernel, it won't be upgradable through your distribution's package manager.

If you use a rolling release, such as Arch or openSUSE Tumbleweed, you will receive the 5.15 kernel much sooner than if your distribution of choice is a static release. We might find kernel 5.15 land in Ubuntu 22.04, which will be released in late April 2022. So, unless you have an absolutely pressing need for these newest additions, your best bet is to hold off until your distribution maintainers include 5.15 in the official release.

Kernel 5.15: A small but mighty Halloween release

It might be smaller than the last few kernels, but with well above 10,000 non-merge changes, the latest Linux kernel still packs a punch. Released on October 31, kernel 5.15 brings lots of exciting new features. For example, ksmbd has been merged, which provides a simple SMB3 server implementation, and a potential user for the case sensitive filesystem support code Gabriel upstreamed in the 5.2 kernel. Another noteworthy highlight is the real-time preemption locking code, which finally hit mainline after 17 years! Meanwhile, in the embedded space, we expect to soon see processors hitting the market that have CPU cores with asymmetric behaviour (e.g. some cores only support 64 bit and some cores only supporting 32 bit). Scheduling a 64 bit task on a 32 bit CPU core would be fatal and the new scheduler will avoid this thanks to Arm.

As usual, our Collabora engineers haven't been slacking either, so let's have a look at their contributions to this kernel release.

Short Topix: Linux Kernel 5.15 Gets Improved NTFS Driver, LTS Designation

On October 31, 2021, Linus Torvalds announced the release of version 5.15 of the Linux kernel. Of particular note is the merging of the NTFS driver into the kernel. That driver came from Paragon Software, and is their first submission to the Linux kernel. That alone caused some anxiety, marking their first voyage into what was uncharted waters for them. Torvalds provided the nudge, and the code was included into the kernel.

In other changes to the Linux kernel, according to an article on The Register:

"Samsung's SMB3 file server ksmbd has also made it in, described as "a new kernel module which implements the server-side of the SMB3 protocol."

Samsung said that it provides optimized performance, but also that "the bigger goal is to add new features more rapidly (eg, RDMA aka 'smbdirect', and recent encryption and signing improvements to the protocol) which are easier to develop on a smaller, more tightly optimized kernel server than for example in Samba." ...

Another notable feature is DAMON (Data Access Monitor) which originated from Amazon and which can be used for advanced memory management optimization.

DAMON is designed to be accurate, lightweight and scalable, and according to maintainer SeongJae Park, mitigates "problems with [core] mechanisms" currently implemented in the kernel."

Torvalds characterized the version 5.15 update as relatively calm and small.