Linux 5.3 Kernel to be Released

Huge amount of updates, improvements, changes and new features awaits all Linux users
17 September 2019   596

After two months of development, Linus Torvalds introduced the Linux 5.3 kernel release. Among the most notable changes: support for AMD Navi GPUs, Zhaoxi processors, and Intel Speed ​​Select power management technology, the ability to use umwait instructions to wait without using loops, increasing the interactivity utilization clamping mode for asymmetric CPUs, the pidfd_open system call, the ability to use IPv4 addresses from the subnet 0.0.0.0/8, the possibility of hardware acceleration of nftables, support for HDR in the DRM subsystem, integration of the ACRN hypervisor.

In the announcement of the new release, Linus reminded all developers of the main rule of kernel development - maintaining the invariance of behavior for user space components. Changes in the kernel should in no way violate already running applications and lead to user-level regressions. At the same time, a violation of behavior can cause not only a change in the ABI, removal of outdated code or errors, but also an indirect effect of correctly working useful improvements. As a good example, the useful optimization in Ext4 code was discarded, which reduces the number of accesses to the drive by disabling the read-ahead inode table for small I / O requests.

Optimization has led to the fact that, due to a decrease in disk activity, the entropy for the random number generator getrandom () began to accumulate more slowly and in some configurations, under certain circumstances, there could be hangs during loading until the entropy pool is full. Since the optimization is really useful, a discussion arose among the developers, in which it was proposed to eliminate the problem by disabling the default blocking mode of the getrandom () call with the addition of an optional flag to wait for entropy, but such a change will affect the quality of random numbers at the initial stage of loading. In the change rollback commit, Linus noted that he plans to bring the optimization back as soon as the problem with getrandom () is resolved.

The new version adopted 15794 patches from 1974 developers, the patch size is 92 MB (the changes affected 13986 files, 258419 lines of code were added, 599137 lines were deleted). About 39% of all the changes presented in 5.3 are related to device drivers, about 12% of changes are related to updating the code specific to hardware architectures, 11% are connected to the network stack, 3% to file systems and 3% to internal kernel subsystems.

Get more information about the new features and from the mailing.

Oracle to Release Unbreakable Kernel R5U3

The update for the kernel, that can be used as alternative for Red Hat Enterprise Linux used in the Oracle Linux is based on the Linux 4.14 
25 March 2020   187

Oracle has released the third functional update for the Unbreakable Enterprise Kernel R5 kernel, positioned for use in the Oracle Linux distribution as an alternative to the regular kernel package from Red Hat Enterprise Linux. The kernel is available for x86_64 and ARM64 architectures (aarch64). Kernel sources, including breakdowns into individual patches, are published in the public Oracle Git repository.

The Unbreakable Enterprise Kernel 5 package is based on the Linux 4.14 kernel (UEK R4 was based on the 4.1 kernel), which is supplemented with new features, optimizations and fixes, as well as tested for compatibility with most applications running in RHEL and specially optimized for working with industrial software and Oracle hardware. Installation and src packages with the UEK R5U1 kernel are prepared for Oracle Linux 7 (there are no obstacles to using this kernel in similar versions of RHEL, CentOS and Scientific Linux).

Key improvements:

  • Improved support for 64-bit systems based on the ARM architecture. Updated drivers for ARM.
  • InfiniBand includes on-demand paging support, which allows you to reflect memory through a processor for accessing unallocated pages of memory (page faults), i.e. consume memory when it is actually being used.
  • In XFS, a deadlock was eliminated, which caused the locks to freeze and not free.
  • CIFS resolved an issue that could lead to POSIX lock leaks and crashes.
  • Bug fixes resolving issues with incompatibility of certain equipment with QEMU / KVM.
  • Device drivers are synchronized with the Linux kernel 4.14.35. The driver for Broadcom Emulex LightPulse Fiber Channel SCSI has been updated to version 12.2.0.13.

Get more at the official blog