Coordination between memory-saving mechanisms in computers that run virtual machines

• US 9,390,028 B2
• Filed: 07/13/2015
• Issued: 07/12/2016
• Est. Priority Date: 10/19/2014
• Status: Active Grant

• Current Assignee: Mellanox Technologies Limited (NVIDIA Corporation)
• Original Assignee: Stratoscale Ltd.
• Inventors: Gordon, Abel, Ben-Yehuda, Muli
• Primary Examiner(s): SCHNEE, HAL W
• Application Number:
  US14/797,201
• Publication Number:
  US 20160110291A1
• Time in Patent Office: 365 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/126 with special data handling, e.g. priority of data or instructions, handling errors or pinning
• CPC Class Codes: G06F 2009/45583 Memory management, e.g. access or allocation
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/152 Virtualized environment, e.g. logically partitioned system
• CPC Class Codes: G06F 2212/657 Virtual address space management
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/5077 Logical partitioning of resources; Management or configuration of virtualized resources specific details on emulation or internal functioning of virtual machines G06F9/455

Abstract

A method includes running in a computer a hypervisor that allocates physical memory pages of the computer to a Virtual Machine (VM). A guest Operating System (OS), a virtual memory and a virtual storage device run in the VM. The guest OS maps the allocated physical memory pages to respective virtual memory pages, retains virtual memory pages that are frequently-accessed by the VM in the virtual memory, and swaps-out virtual memory pages that are rarely-accessed by the VM to the virtual storage. In the hypervisor, one or more of the physical memory pages allocated to the VM are selected, and the corresponding virtual memory pages preventing from being swapped-out by the guest OS, by marking the corresponding virtual memory pages in the guest OS as accessed thus causing the guest OS to regard the corresponding virtual memory pages as frequently-accessed.

Claims

1. A method, comprising:

running in a computer a hypervisor that allocates physical memory pages of the computer to a Virtual Machine (VM);

running in the VM a guest Operating System (OS), a virtual memory and a virtual storage device, wherein the guest OS maps the allocated physical memory pages to respective virtual memory pages, retains virtual memory pages that are frequently-accessed by the VM in the virtual memory, and swaps-out virtual memory pages that are rarely-accessed by the VM to the virtual storage; and

in the hypervisor, selecting one or more of the physical memory pages allocated to the VM, and preventing the corresponding virtual memory pages from being swapped-out by the guest OS, by marking the corresponding virtual memory pages in the guest OS as accessed thus causing the guest OS to regard the corresponding virtual memory pages as frequently-accessed.

2. The method according to claim 1, wherein marking the virtual memory pages as accessed comprises causing the guest OS to regard at least one virtual memory page as frequently-accessed even though the virtual memory page is rarely-accessed.

3. The method according to claim 1, wherein selecting the physical memory pages comprises selecting at least one physical memory page that was deduplicated by the hypervisor.

4. The method according to claim 1, wherein selecting the physical memory pages comprises selecting at least one physical memory page that was swapped-out by the hypervisor from a physical memory of the computer to a physical non-volatile storage device of the computer.

5. The method according to claim 1, wherein marking the virtual memory pages as accessed comprises modifying, by the hypervisor, page-access information maintained by the guest OS.

6. The method according to claim 1, wherein marking the virtual memory pages as accessed comprises reporting the selected physical memory pages to a driver running in the VM, and marking the virtual memory pages as accessed by the driver.

7. The method according to claim 6, wherein marking the virtual memory pages as accessed comprises modifying, by the driver, page-access information maintained by the guest OS.

8. The method according to claim 6, wherein marking the virtual memory pages as accessed comprises accessing the virtual memory pages by the driver.

9. A computer, comprising:

a physical memory; and

a Central Processing Unit (CPU), which is configured to run a hypervisor that allocates physical memory pages of the physical memory to a Virtual Machine (VM), to run in the VM a guest Operating System (OS), a virtual memory and a virtual storage device, wherein the guest OS maps the allocated physical memory pages to respective virtual memory pages, retains virtual memory pages that are frequently-accessed by the VM in the virtual memory, and swaps-out virtual memory pages that are rarely-accessed by the VM to the virtual storage, to select by the hypervisor one or more of the physical memory pages allocated to the VM, and to prevent the corresponding virtual memory pages from being swapped-out by the guest OS, by marking the corresponding virtual memory pages in the guest OS as accessed thus causing the guest OS to regard the corresponding virtual memory pages as frequently-accessed.

10. The computer according to claim 9, wherein the CPU is configured to cause the guest OS to regard at least one virtual memory page as frequently-accessed even though the virtual memory page is rarely-accessed.

11. The computer according to claim 9, wherein the CPU is configured to select the physical memory pages by selecting at least one physical memory page that was deduplicated by the hypervisor.

12. The computer according to claim 9, wherein the CPU is configured to select the physical memory pages by selecting at least one physical memory page that was swapped-out by the hypervisor from a physical memory of the computer to a physical non-volatile storage device of the computer.

13. The computer according to claim 9, wherein the CPU is configured to marking the virtual memory pages as accessed by modifying, by the hypervisor, page-access information maintained by the guest OS.

14. The computer according to claim 9, wherein the CPU is configured to mark the virtual memory pages as accessed by reporting the selected physical memory pages to a driver running in the VM, and marking the virtual memory pages as accessed by the driver.

15. The computer according to claim 14, wherein the CPU is configured to mark the virtual memory pages as accessed by modifying, by the driver, page-access information maintained by the guest OS.

16. The computer according to claim 14, wherein the CPU is configured to mark the virtual memory pages as accessed by accessing the virtual memory pages by the driver.

17. A computer software product, the product comprising a tangible non-transitory computer-readable medium in which program instructions are stored, which instructions, when read by a Central Processing Unit (CPU) of a computer, cause the processor to run a hypervisor that allocates physical memory pages of a physical memory of the computer to a Virtual Machine (VM), to run in the VM a guest Operating System (OS), a virtual memory and a virtual storage device, wherein the guest OS maps the allocated physical memory pages to respective virtual memory pages, retains virtual memory pages that are frequently-accessed by the VM in the virtual memory, and swaps-out virtual memory pages that are rarely-accessed by the VM to the virtual storage, to select by the hypervisor one or more of the physical memory pages allocated to the VM, and to prevent the corresponding virtual memory pages from being swapped-out by the guest OS, by marking the corresponding virtual memory pages in the guest OS as accessed thus causing the guest OS to regard the corresponding virtual memory pages as frequently-accessed.