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Linux 4.14 Provides Long-Term Support and Larger Memory Limits

By Sean Michael Kerner (Send Email)
Posted November 13, 2017


Linus Torvalds officially released the Linux 4.14 kernel on Nov. 12, providing users of the open-source operating system with new features and long-term support. Linux 4.14 is a special release in that it has been designated as an LTS (Long Term Support) release, meaning it will be maintained for at least the next two years.

Linux 4.14 is the fifth new major Linux kernel release in 2017, following the Linux 4.13 kernel that debuted on Sept. 3.

"Go out and test the new 4.14 release, that is slated to be the next LTS kernel -- and start sending me pull requests for the 4.15 merge window," Torvalds wrote in his release announcement.

What's New in Linux 4.14

Among the new capabilities that landed in the Linux 4.14 update is the possibility for larger memory capacity utilization. The original x86-64 specification in Linux allowed for 4-level memory paging, providing a maximum of 256 TiB of virtual address space and 64 TiB of physical address space. A TiB, or Tebibyte, is approximately 1.1 Terabytes.

"To overcome the limitation, upcoming hardware will introduce support for 5-level paging," Intel developer Kirill Shutemov wrote in his Linux commit message. "It is a straightforward extension of the current page table structure, adding one more layer of translation."

"It bumps the limits to 128 PiB of virtual address space and 4 PiB of physical address space," he added. "This ought to be enough for anybody."

Additionally, Linux 4.14 now also provides support for AMD's Secure Memory Encryption (SME) capability.

"SME provides the ability to mark individual pages of memory as encrypted using the standard x86 page tables," the SME documentation states. "A page that is marked encrypted will be automatically decrypted when read from DRAM and encrypted when written to DRAM. SME can therefore be used to protect the contents of DRAM from physical attacks on the system."

Memory utilization is further improved in Linux 4.14 with support for heterogeneous memory management (HMM) for GPUs.

"HMM is a set of helpers to facilitate several aspects of address space sharing and device memory management," Red Hat developer Jerome Glisse wrote in his Linux commit message. "Unlike existing sharing mechanisms that rely on pining pages use by a device, HMM relies on mmu_notifier to propagate CPU page table update to device page table."

Sean Michael Kerner is a senior editor at ServerWatch and InternetNews.com. Follow him on Twitter @TechJournalist.

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