Systems and methods for managing data input/output operations

• US 8,874,823 B2
• Filed: 02/15/2011
• Issued: 10/28/2014
• Est. Priority Date: 02/15/2011
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Intellectual Property Holdings 2, LLC
• Inventors: Joshi, Vikram, Luan, Yang, Apte, Manish R., Vidwans, Hrishikesh A., Brown, Michael F.
• Primary Examiner(s): CARDWELL, ERIC
• Application Number:
  US13/028,149
• Publication Number:
  US 20120210043A1
• Time in Patent Office: 1,351 Days
• Field of Search: None
• US Class Current: 711/6
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/084 with a shared cache
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G06F 2009/45579 I/O management, e.g. providing access to device drivers or storage
• CPC Class Codes: G06F 2212/1021 Hit rate improvement
• CPC Class Codes: G06F 2212/452 Instruction code
• CPC Class Codes: G06F 2212/604 Details relating to cache allocation
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/45558 Hypervisor-specific management and integration aspects

Abstract

Systems and methods for managing data input/output operations are described. In one aspect, a device driver identifies a data read operation generated by a virtual machine in a virtual environment. The device driver is located in the virtual machine and the data read operation identifies a physical cache address associated with the data requested in the data read operation. A determination is made regarding whether data associated with the data read operation is available in a cache associated with the virtual machine.

Claims

1. A method, comprising:

identifying a data read operation by use of a storage driver of a virtual machine, the data read operation generated by the virtual machine and sent to a primary storage system, wherein the virtual machine is configured for operation within a hypervisor on a host computing device;

determining, by way of a cache management system operating within the virtual machine, whether data associated with the identified data read operation is available in a cache of the host computing device, wherein the cache is managed by a cache provisioner that is accessible to a plurality of virtual machines operating within the hypervisor; and

redirecting the identified data read operation to the cache provisioner in response to determining that the data is available in the cache.

2. The method of claim 1, further comprising servicing the identified data read operation by use of data retrieved from the cache of the host computing device.

3. The method of claim 1, wherein the data read operation is identified by use of a device driver configured for operation within a guest operating system of the virtual machine.

4. The method of claim 3, wherein the device driver is an input/output driver.

5. The method of claim 1, further comprising maintaining a set of cache tags within the virtual machine corresponding to cache resources allocated to the virtual machine by the cache provisioner.

6. The method of claim 1, further comprising accessing a cache tag stored in the virtual machine that associates a storage I/O address associated with the data read operation with a cache address.

7. The method of claim 6, wherein cache tags of the virtual machine are stored linearly in random access memory of the virtual machine.

8. The method of claim 6, wherein the cache tag is associated with a particular cache page managed by the cache provisioner.

9. A system, comprising:

a cache manager configured for operation within a virtual machine, wherein the virtual machine is configured for operation within a hypervisor of a host computing device; and

an input/output driver configured to operate within the virtual machine, wherein the input/output driver is configured to intercept input/output operations associated with the virtual machine that pertain to a primary storage system, and to send the intercepted input/output operations to the cache manager;

wherein the cache manager is configured to request data from a cache provisioner managing a data cache configured for operation within the hypervisor in response to intercepted input/output operations of the virtual machine.

10. The system of claim 9, wherein the data cache comprises a flash memory device.

11. The system of claim 9, wherein the data cache comprises a solid state drive.

12. The system of claim 9, wherein the data cache includes volatile memory.

13. The system of claim 9, wherein the cache provisioner is configured to allocate cache resources to each of a plurality of virtual machines operating within the hypervisor of the host computing device.

14. The system of claim 13, wherein the cache manager maintains cache tags in a memory of the virtual machine that associate storage I/O addresses of the primary storage system with cache storage resources allocated to the virtual machine by the cache provisioner.

15. The system of claim 9, wherein the cache management system is configured to send intercepted input/output operations to the cache provisioner operating in the hypervisor for processing.

16. The system of claim 9, wherein the cache provisioner is configured to allocate cache pages of the data cache to a plurality of virtual machines operating within the hypervisor of the host computing device and to communicate information regarding allocated cache resources to each of the plurality of virtual machines.

17. The system of claim 9, wherein the cache provisioner is configured to dynamically provision input/output operation capacity to a plurality of virtual machines operating within the hypervisor of the host computing device.

18. The system of claim 17, wherein the cache provisioner is further configured to communicate information regarding allocated input/output operation capacity to each of the plurality of virtual machines.

19. The system of claim 9, wherein the cache provisioner is configured to allocate cache storage capacity to a plurality of virtual machines operating within the hypervisor of the host computing device, and wherein the cache provisioner is further configured to maintain a listing of valid data of the virtual machines stored in the data cache.

20. The system of claim 9, wherein the cache manager is configured to identify data candidates for removal from the data cache.

21. The system of claim 9, wherein the cache manager comprises a multi-bit clock timer configured to identify data stored in the data cache that has not been recently accessed.

22. The system of claim 9, wherein the cache manager comprises a clock timer configured to identify data stored in the data cache that has not been recently accessed, wherein the clock timer comprises a plurality of temporal trigger intervals.

23. The system of claim 9, wherein the cache manager is configured to maintain a set of cache tags representing cache capacity allocated to the virtual machine by the cache provisioner, and to adjust the number of cache tags in the maintained set in response to the cache provisioner modifying the cache capacity allocated to the virtual machine.

24. The system of claim 9, wherein the virtual machine comprises one or more of a virtual desktop and a server application.

25. The system of claim 9, wherein the cache provisioner is configured to allocate cache resources to a plurality of virtual machines operating within the hypervisor and control access to data of the virtual machines stored in the data cache.

26. The system of claim 9, wherein the hypervisor comprises a virtualization kernel configured to manage the operation of the virtual machine.

27. A non-transitory computer-readable storage medium comprising instructions for execution by a processor of a computing device, wherein the instructions are configured to cause the computing device to perform operations, comprising:

provisioning cache storage resources of a cache storage device to respective virtual machines operating within a virtual computing environment within a virtualization kernel of a host computing device;

informing the virtual machines of the cache storage resources provisioned to the respective virtual machines;

receiving input/output requests that pertain to a primary storage device from the virtual machines, wherein the received input/output requests are redirected within the respective virtual machines; and

servicing the received input/output requests by use of the cache storage device, in accordance with the cache storage resources provisioned to the respective virtual machines.

28. A method, comprising:

maintaining cache tags within a particular virtual machine configured for operation within a virtualization environment of a host computing device, such that the cache tags correspond to cache capacity allocated to the particular virtual machine in a cache storage resource accessible to a plurality of virtual machines operating within the virtualization environment;

identifying a storage request generated within the particular virtual machine; and

redirecting the identified storage request to the cache storage resource in response to determining that data corresponding to the identified storage request has been admitted to the cache storage resource by use of the cache tags maintained within the particular virtual machine.

29. The method of claim 28, wherein the storage request is identified by use of an input/output driver of the particular virtual machine.

30. The method of claim 28, further comprising receiving an indication of the cache capacity allocated to the particular virtual machine from a cache provisioner.

31. The method of claim 30, further comprising modifying the cache tags maintained within the particular virtual machine in response to an indication of a change to the cache capacity allocated to the particular virtual machine by one or more of removing one or more of the cache tags and adding one or more cache tags.