Linux Plumbers Conf 2011

One Line Summary

Abstract

Modern memory controller (like those supporting DDR3 standard),
have created an opportunity to conserve the power consumed by the memory subsystem by supporting multiple power savings states. Designing a cooperative VM framework in Linux OS could help save power in the memory subsystem. This presentation will cover some of the core kernel VM infrastructure we are proposing, that could be used for memory power management in such hardware platforms.

The memory hardware offers different level of support to manage power. For example, the TI OMAP4 board supports Partial Array Self-refresh and the Samsung Exynos supports the two memory controllers to be in different power state. At present, the Linux VM is agnostic to the memory hardware topology and cannot take it into account in the memory allocation/deallocation operations. In this talk, we discuss a memory regions framework that exposes the physical memory characteristics to the virtual memory manager and enable it to make power-aware memory decision. Besides power management, the memory regions infrastructure can also be used for doing contiguous memory allocations. This approach may
provide a better and more fine grained alternative to NUMA-node based approach to power management.

In this presentation we will discuss the different VM approaches to solving this problem, the pitfalls, challenges and future work. It would also be beneficial to embedded system designers and application developers who would like to see a programmable interface into the Linux VM subsystem for optimal use of memory resources under certain allocation constraints or special use cases.

Presentation Materials

Speakers

• Ankita Garg

  IBM
  • Blog: http://linux-hacks.blogspot.com/

  Biography

  Ankita Garg is a kernel developer at LTC (Linux Technology Center), IBM, India Software Labs. Ankita has been involved in the Linux kernel for about four years now. She is presently working on adding support in the Linux kernel to exploit the memory power management capabilities of embedded platforms. In the past she has developed a memory reference pattern capture instrumentation infrastructure in the kernel. She has also worked in the areas of RAS and Real-Time Linux kernel. Ankita joined IBM as a fresh college graduate from P.E.S.I.T, Bangalore.

• Vaidyanathan Srinivasan

  IBM
  Biography

  Vaidy is a kernel developer at IBM Linux Technology Center. He has been working on improving energy efficiency of Linux running on enterprise hardware including Linux on IBM POWER platforms by exploiting platform power saving features and improve efficiency.