The situation is looking good for seeing the Linux 5.4 kernel debut as stable with today's release of 5.4-rc4 being another "normal" release that isn't coming in too heavy.

While mid-way through the Linux 5.4 development cycle with RC4 due out on Sunday, a number of memory management fixes just hit the mainline kernel.

Thanks to a Linux kernel fix that is likely to be back-ported to the various stable series, highly threaded software running under CFS quotas for enforcing CPU limits are about to be much faster. At least in a synthetic test case, the kernel fix yields a 30x improvement in performance.

User-space API additions and changes (granted, no ABI breakage permitted for the mainline Linux kernel) to Linux Direct Rendering Manager (DRM) drivers is done fairly easily by their developers and possibly without enough thought. Linux DRM subsystem co-maintainer David Airlie has issued a proposal that would make user-space API alterations more strictly reviewed.

Linus Torvalds has just issued the third weekly release candidate of the forthcoming Linux 5.4 kernel that should debut as stable before the end of November.

Linus Torvalds is back on his Sunday release regiment with having just declared the Linux 5.4-rc2 test release and also took the opportunity to have some fun by shifting the kernel's codename to be the Nesting Opossum, replacing the Bobtail Squid.

Linux 5.4 is already exciting with its many new features and changes but was made even more so on Friday night with the honoring of the latest DRM fixes pull request that includes the "fix" of enabling LRU bulk moves for the AMDGPU DRM driver!

It's coming one day late due to the last minute entropy/RNG patches to improve the random behavior during boot time (among other late patches), but Linus Torvalds has just tagged Linux 5.4-rc1 as what will be the last major stable kernel release of 2019.

Linux 5.4-rc1 didn't end up being released on Sunday night as is tradition but instead there were some last-minute critical patches that landed around the kernel's handling of the random number generator / entropy at boot-time.

It turns out Linux 5.3 shipped with potentially subpar performance for the allocation of hugepages but that should be rectified in the now open Linux 5.4 cycle for trying to provide a sane default allocation strategy on NUMA boxes.

While yesterday Linus Torvalds was still undecided on whether to pull in the long-revised "LOCKDOWN" kernel patches and wanted to review them patch-by-patch, following that lengthy examination he has decided to indeed land this opt-in restricted functionality for Linux 5.4.

Added back during the Linux 5.1 cycle was IO_uring for fast and efficient I/O. This new interface allows for queue rings to be shared between the application and kernel to avoid excess copies and other efficiency improvements over the existing Linux AIO code. With Linux 5.4, IO_uring is in even better shape.

The Linux 5.4 kernel merge window is set to close this weekend and as of writing it's still yet to be decided by Linus Torvalds whether to accept the kernel "lockdown" functionality feature for this release.

It has surprisingly taken until the Linux 5.4 kernel in 2019 to potentially have a single unified way for calculating the size of a member of a struct within the kernel: Linux 5.4 is looking at adding a new sizeof_member macro for handling this purpose.

The "char/misc" changes for the Linux 5.4 are as eventful as ever.

While we've known about the many features for a while if you are a faithful Phoronix reader, today the Direct Rendering Manager (DRM) graphics driver changes were sent in for the Linux 5.4 kernel.

Greg Kroah-Hartman began volleying his Linux 5.4 kernel pull requests today of the subsystems he oversees. The most significant of this morning's pull requests are the staging area changes that include the Microsoft exFAT file-system support.

The Linux 5.4 scheduler changes are fairly exciting on multiple fronts.

A kernel patch from CodeWeavers is landing in the Linux 5.4 kernel and will help some 64-bit Windows games run nicely under Wine (and the likes of CrossOver / Valve's Proton) with newer Intel and AMD systems.

Linus Torvalds just went ahead and released the Linux 5.3 kernel as stable while now opening the Linux 5.4 merge window.

The Linux 5.3 kernel is expected to be released as stable today and that will mark the opening of the two-week Linux 5.4 merge window. Here is a look ahead at some of the material expected to make it into this next version of the Linux kernel that will also be the last major stable release of 2019.

While the Linux kernel is well known for not offering a stable API/ABI, Google and other enterprise Linux distribution vendors tend to aim at providing their own stable ABI for the lifespan of their products. Google engineers talked in Portugal this week at Linux Plumbers Conference 2019 about some of their means to maintaining a stable API/ABI for Android's Linux kernel.

Borislav Petkov has taken to improve the Linux kernel's memset function with it being an area previously criticzed by Linus Torvalds and other prominent developers.

With Hyper Threading continuing to look increasingly unsafe in data centers / shared computing environments in light of all the speculative execution vulnerabilities exposed thus far particularly with L1TF and MDS having no SMT-secure mitigation, DigitalOcean continues working on their Linux kernel "core scheduling" patches so they can still make use of HT/SMT in a sane and safe manner.

Linux 5.3 isn't being released until this weekend after being delayed by one week, but already there have been a few early pull requests submitted for the to-be-opened Linux 5.4 merge window.

As expected, Linus Torvalds today released the Linux 5.3-rc8 kernel rather than opting for the stable Linux 5.3.

The Linux 5.3 kernel is fit enough to be released today after another quiet week following 5.3-RC7. But due to the Linux Kernel Summit happening this week and Linus Torvalds traveling for that, he's expected to delay the stable kernel release until next weekend so as to not open the Linux 5.4 merge window until he returns from the event.

Roman Gushchin of Facebook's Linux kernel engineering team has proposed a new slab memory controller for the Linux kernel.

The Schedutil CPU frequency scaling governor has been around for a few years and has gotten better over time but in our own tests we still find it frequently not being as competitive to the "performance" governor and others. However, in the future Schedutil might become the default and perhaps only governor.

It appears Linus Torvalds is spending some time away from his computers this US Labor Day weekend with the Linux 5.3-rc7 kernel test release coming one day late.