News, tips, partners, and perspectives for the Oracle Linux operating system and upstream Linux kernel work

Announcing the Unbreakable Enterprise Kernel Release 4 Update 6 for Oracle Linux

Avi Miller
Senior Solutions Architect

The Oracle Linux operating system is engineered for an open cloud infrastructure. It delivers leading performance, scalability and reliability for enterprise SaaS and PaaS workloads as well as traditional enterprise applications. Oracle Linux Support offers access to award-winning Oracle support resources and Linux support specialists, zero-downtime updates using Ksplice, additional management tools such as Oracle Enterprise Manager, and lifetime support, all at a low cost. And unlike many other commercial Linux distributions, Oracle Linux is easy to download, completely free to use, distribute, and update.

What's New?

The Unbreakable Enterprise Kernel Release 4 Update 6 uses the 4.1.12-112.14.1 version and includes several new features, functionality and bug fixes across a range of subsystems.

Notable changes

  • Automatic NUMA balancing is disabled by default
    In this update, the auto-enabling of automatic Non-uniform memory access (NUMA) balancing has been disabled. This change addresses several issues that were encountered on systems with multiple NUMA nodes, where automatic NUMA balancing was enabled. Symptoms that were reported included high iowait times and numerous processes (like Oracle DB processes) observed in the D state, that were sitting on the wait_on_page_bit() function in the process stack.
  • Deferred compaction of Transparent Hugepages is enabled
    The deferred compaction feature for Transparent Huge Pages (THP) has been backported from the mainline kernel, and the default defrag behavior has been set to madvise. This resolves an issue where THP could cause application stalls in the event that a huge page allocation from THP takes a long time due to memory fragmentation.

Crypto API

  • Addition of the ccp driver
    The ccp driver provides support for the AMD Cryptographic Coprocessor (CCP). The AMD CCP provides hardware encryption, hashing and other related operations.
  • Jitter entropy RNG added
    The Jitter Entropy Random Number Generator (RNG) is a feature that collects entropy through CPU timing differences to the Linux kernel.


  • I/O provider for NFS
    In this update, the DTrace I/O provider probes for start, done, read and write requests have been added for NFS. 
  • lockstat provider added
    DTrace lockstat support enables the dynamic tracing of kernel locking events, including which locks are most frequently used, which locks exhibit the most contention and which locks are held the longest.
  • Packaging changes
    Starting with the release of the Unbreakable Enterprise Kernel Release 4 Update 6, the dtrace-modules, dtrace-modules-provider-headers and dtrace-modules-shared-headers packages are no longer distributed. The functionality provided by these packages is now included in the base kernel-uek and associated header packages.

For more details on these and other new features and changes, please consult the Release Notes for the UEK R4 Update 6 for Oracle Linux 6 or the Release Notes for the UEK R4 Update 6 for Oracle Linux 7.

Supported upgrade path

Customers can upgrade existing Oracle Linux 6 and Oracle Linux 7 servers using the Unbreakable Linux Network or the Oracle Linux Yum Server.

Software Download

Oracle Linux can be downloaded, used and distributed free of charge and all updates and errata are freely available. This allows you to decide which of your systems require a support subscription and makes Oracle Linux an ideal choice for your development, testing and production systems. You decide which support coverage is the best for each of your systems individually, while keeping all of your systems up-to-date and secure. For customers with Oracle Linux Premier Support, you also receive access to zero-downtime kernel updates using Oracle Ksplice and support for Oracle OpenStack.


UEK R4 Update 6 is fully compatible with the previous UEK R4 updates. The kernel ABI for UEK R4 will remain unchanged in all subsequent updates to the initial release. In this release, there are changes to the kernel ABI relative to UEK R3 that require recompilation of third-party kernel modules on the system. Before installing UEK R4, verify its support status with your application vendor.

Resources – Oracle Linux


Software Download


Community Pages

Social Media

Data Sheets, White Papers, Videos, Training, Support & more

Product Training and Education

Oracle Linux - http://oracle.com/education/linux

Be the first to comment

Comments ( 0 )
Please enter your name.Please provide a valid email address.Please enter a comment.CAPTCHA challenge response provided was incorrect. Please try again.