SYSTEM AND METHOD FOR CONTROLLING RESOURCE REVOCATION IN A MULTI-GUEST COMPUTER SYSTEM

• US 20090025006A1
• Filed: 09/23/2008
• Published: 01/22/2009
• Est. Priority Date: 09/22/2000
• Status: Active Grant

• Current Assignee: VMware, Inc. (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: WALDSPURGER, Carl A.
• Granted Patent: US 8,145,763 B2
• Time in Patent Office: Days
• US Class Current: 718/104
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/0284 Multiple user address space allocation, e.g. using different base addresses interprocessor communication G06F15/163
• CPC Class Codes: G06F 2009/45583 Memory management, e.g. access or allocation
• CPC Class Codes: G06F 2209/5014 Reservation
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 8/4434 Reducing the memory space required by the program code
• CPC Class Codes: G06F 9/5011 the resources being hardware resources other than CPUs, Servers and Terminals
• 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
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

At least one guest system, for example, a virtual machine, is connected to a host system, which includes a system resource such as system machine memory. Each guest system includes a guest operating system (OS). A resource requesting mechanism, preferably a driver, is installed within each guest OS and communicates with a resource scheduler included within the host system. If the host system needs any one the guest systems to relinquish some of the system resource it currently is allocated, then the resource scheduler instructs the driver within that guest system'"'"'s OS to reserve more of the resource, using the guest OS'"'"'s own, native resource allocation mechanisms. The driver thus frees this resource for use by the host, since the driver does not itself actually need the requested amount of the resource. The driver in each guest OS thus acts as a hollow “balloon” to “inflate” or “deflate,” that is, reserve more or less of the system resource via the corresponding guest OS. The resource scheduler, however, remains transparent to the guest systems.

Claims

1. A computer system comprising:

a host system including at least one hardware processor and a hardware memory; and

one or more virtual machines, each configured to run on said at least one hardware processor using regions of the hardware memory that have been allocated thereto,

wherein each of the virtual machines includes (i) a guest operating system that allocates guest physical memory to software modules that are executed therein, and (ii) a memory reservation software module that is executed in response to a memory quantity request from the host system, and

wherein a portion of the hardware memory corresponding to the guest physical memory that is allocated to the memory reservation software module by the guest operating system is made available to the host system for reallocation.

2. The computer system according to claim 1, wherein the host system includes a resource scheduler for allocating the hardware memory.

3. The computer system according to claim 2, wherein the memory reservation software module is a driver installed within a respective guest operating system.

4. The computer system according to claim 2, wherein the memory reservation software module is a user-level application loaded in the virtual machine and running on the guest operating system.

5. The computer system according to claim 2, wherein:

upon an increase in the memory quantity request issued by the resource scheduler to a virtual machine, the guest operating system of the virtual machine allocates to the memory reservation software module a corresponding quantity of guest physical memory such that the portion of the hardware memory corresponding to the allocated guest physical memory becomes available for reallocation by the host system; and

upon a decrease in the memory quantity request issued by the resource scheduler to a virtual machine, the guest operating system releases any prior allocation of a corresponding quantity of guest physical memory such that the portion of the hardware memory corresponding to the released guest physical memory becomes available for use by the virtual machine.

6. The computer system according to claim 1, wherein, when the memory reservation software module is executed, the guest operating system changes the amount of the guest physical memory allocated to applications and drivers loaded in the virtual machine and running on the guest operating system.

7. The computer system according to claim 1, wherein the guest physical memory of each virtual machine is mapped to various regions of the hardware memory.

8. In a computer system that comprises a host system including a host operating system and a hardware memory, and at least one virtual machine operatively connected as a guest system running on the host system and having a guest operating system operable to address and allocate guest physical memory, wherein the guest physical memory is mapped to various regions of the hardware memory, a method comprising:

issuing a memory quantity request to a virtual machine;

executing a memory reservation software module in the virtual machine in response to the memory quantity request;

allocating guest physical memory to the memory reservation software module; and

assigning a portion of the hardware memory corresponding to the guest physical memory allocated to the memory reservation software module to another resource.

9. The method according to claim 8, wherein said another resource is another virtual machine.

10. The method according to claim 8, wherein the amount of guest physical memory allocated to the memory reservation software module is equal to the amount of guest physical memory specified in the memory quantity request.

11. The method according to claim 10, wherein:

upon an increase in the memory quantity request issued to the virtual machine, the guest operating system of the virtual machine allocates to the memory reservation software module a corresponding quantity of guest physical memory such that the portion of the hardware memory corresponding to the allocated guest physical memory becomes available for allocation by the host system to another resource; and

upon a decrease in the memory quantity request issued to the virtual machine, the guest operating system releases any prior allocation of a corresponding quantity of guest physical memory such that the portion of the hardware memory corresponding to the released guest physical memory becomes available for use by the virtual machine.

12. The method according to claim 8, wherein, when the memory reservation software module is executed, the guest operating system changes the amount of the guest physical memory allocated to applications and drivers loaded in the virtual machine and running on the guest operating system.

13. The method according to claim 8, further comprising:

limiting the rate at which the guest physical memory is allocated to the memory reservation software module to a maximum reservation change rate.

14. The method according to claim 13, further comprising:

adjusting the maximum reservation change rate.

15. The method according to claim 8, wherein the host system includes a resource scheduler for allocating the hardware memory, and the memory quantity request is issued by the resource scheduler to a virtual machine.

16. A computer system comprising:

a host system including at least one hardware processor, a hardware memory, and a resource scheduler for allocating the hardware memory; and

a guest system that is operatively connected to the host system and programmed to;

(i) receive a memory quantity request from the resource scheduler, (ii) execute a memory reservation software module in response to the memory quantity request, and (iii) allocate guest physical memory to the memory reservation software module,

wherein the resource scheduler makes available a portion of the hardware memory corresponding to the guest physical memory allocated to the memory reservation software module to another guest system.

17. The computer system according to claim 16, wherein the amount of guest physical memory allocated to the memory reservation software module is equal to the amount of guest physical memory specified in the memory quantity request.

18. The computer system according to claim 17, wherein:

upon an increase in the memory quantity request issued to the guest system, an operating system of the guest system allocates to the memory reservation software module a corresponding quantity of guest physical memory such that the portion of the hardware memory corresponding to the allocated guest physical memory available for allocation by the resource scheduler to another guest system; and

upon a decrease in the memory quantity request issued to the guest system, an operating system of the guest system releases any prior allocation of a corresponding quantity of guest physical memory such that the portion of the hardware memory corresponding to the released guest physical memory available for use by the guest system.

19. The computer system according to claim 16, wherein, when the memory reservation software module is executed, an operating system of the guest system changes the amount of the guest physical memory allocated to applications and drivers loaded in the guest system and running on the operating system of the guest system.

20. The computer system according to claim 16, wherein the guest system is programmed to limit the rate at which the guest physical memory is allocated to the memory reservation software module to a maximum reservation change rate.

21. The computer system according to claim 20, wherein the guest system is programmed to adjust the maximum reservation change rate.

22. The computer system according to claim 16, wherein the memory reservation software module is a driver installed within an operating system of the guest system.

23. The computer system according to claim 16, wherein the memory reservation software module is a user-level application loaded in the guest system and running on an operating system of the guest system.