System and method for host management of discardable objects

• US 9,104,686 B2
• Filed: 12/30/2011
• Issued: 08/11/2015
• Est. Priority Date: 12/16/2008
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Jogand-Coulomb, Fabrice, Patel, Shalin, Kavanagh, Brendan, Hahn, Judah Gamliel
• Primary Examiner(s): BROWN, SHEREE N
• Application Number:
  US13/341,785
• Publication Number:
  US 20120173594A1
• Time in Patent Office: 1,320 Days
• Field of Search: 707/812
• US Class Current: 1/1
• CPC Class Codes: G06F 16/1737 for reducing power consumption or coping with limited storage space, e.g. in mobile devices saving storage space on storage devices G06F3/0608; power saving in storage systems G06F3/0625
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

A method and system of managing data in a storage device is provided. The method includes receiving a request to store content in a storage device. If the content is discardable content, the content is divided into a plurality of discardable data objects, each associated with at least one type of discarding priority data. The discardable data objects in the storage device are managed based on the discarding priority data associated with each discardable data object. Management of discardable objects may include selection and deletion of discardable objects based on discarding priority data, as well as further subdivision of existing discardable objects, to maintain a desired amount of free space on the storage device. The system may include a host having a processor and a storage device interface configured to execute the method, or a storage device having a processor configured to execute the disclosed methods.

Claims

1. A method for host management of a non-volatile memory, the method comprising:

in a host to which a non-volatile memory is operatively coupled;

in response to a request to store at least a portion of content in the non-volatile memory, dividing the at least a portion of the content into a plurality of discardable data objects and associating each discardable data object with discarding priority data; and

in response to a request to store new data or new discardable content when the non-volatile memory has less than a predetermined amount of free space to accommodate the new data or new discardable content;

subdividing at least one of the plurality of discardable data objects into new discardable data objects;

arranging a list of the discardable data objects and new discardable data objects for automatic deletion, the arranged list having an order based on respective discarding priority data; and

identifying for deletion discardable data objects or new discardable data objects in the arranged list sufficient to achieve the predetermined amount of free space.

2. The method of claim 1, wherein associating each discardable data object with discarding priority data comprises associating at least one discardable data object of the content with different discarding priority data than discarding priority data of a discardable data object of different content.

3. The method of claim 1, further comprising updating an existing discarding priority data of at least one discardable data object.

4. The method of claim 3, wherein associating each discardable data object with a discarding priority data comprises assigning a first of a sequence of discardable data objects of the discardable content discarding priority data such that the first of the sequence has a lower likelihood of deletion than any remaining discardable data objects of the content.

5. The method of claim 3, where updating the existing discarding priority data comprises updating the existing discarding priority data with different discarding priority data than that of another discardable data object of the content.

6. The method of claim 5, wherein updating the existing discarding priority data of at least one discardable data object comprises changing the existing discarding priority data based on at least one dynamic priority criteria determined when the at least one discardable data object is accessed.

7. The method of claim 6, wherein the at least one dynamic priority criteria comprises a time of last access of the discardable data object.

8. The method of claim 1, wherein identifying for deletion comprises selectively identifying for deletion, based on respective discarding priority data for the discardable data objects, one or more discardable data objects without identifying all discardable data objects for the content in order to free space in the non-volatile memory.

9. The method of claim 1, wherein identifying for deletion comprises selectively identifying for deletion one or more discardable data objects of a first content, without identifying all discardable data objects for the first content, in response to receipt of another content wherein a number of discardable data objects of different content is maximized.

10. A host system for managing a non-volatile memory, the host system comprising:

a host processor and a non-volatile memory interface configured for communication with the non-volatile memory;

wherein the host processor is configured to;

in response to a request to store at least a portion of content in the non-volatile memory, divide the at least a portion of the content into a plurality of discardable data objects and associate each discardable data object with discarding priority data; and

in response to a request to store new data or new discardable content when in the non-volatile memory has less than a predetermined amount of free space to accommodate the new data or new discardable content;

subdivide at least one of the plurality of discardable data objects into new discardable data objects;

arrange a list of the discardable data objects and new discardable data objects for automatic deletion, the arranged list having an order based on respective discarding priority data; and

identify for deletion discardable data objects or new discardable data objects in the arranged list sufficient to achieve the predetermined amount of free space.

11. The host system of claim 10, wherein the host processor is configured to associate at least one discardable data object of the content with different discarding priority data than the discarding priority data of another discardable data object of the content.

12. The host system of claim 11, wherein the host processor is configured to associate a first of a sequence of discardable data objects of the content with discarding priority data such that the first of the sequence has a lower likelihood of deletion than any remaining discardable data objects of the content.

13. The host system of claim 10, wherein the host processor is configured to update existing discarding priority data of at least one discardable data object.

14. The host system of claim 13, wherein the host processor is configured to update existing discarding priority data based on at least one dynamic priority criteria determined when the at least one discardable data object is accessed.

15. The host system of claim 14, wherein the at least one dynamic priority criteria comprises an age of the discardable data object.

16. The host system of claim 10, wherein the host processor is configured to maximize a number of discardable data objects of different contents.

17. A method for managing a non-volatile memory of a memory system operatively coupled with a host, the method comprising:

in a processor of the memory system, where the processor is in communication with non-volatile memory, the processor;

in response to a request to store at least a portion of content in the non-volatile memory, dividing the at least a portion of the content into a plurality of discardable data objects and associating each discardable data object with discarding priority data; and

in response to a request to store new data or new discardable content when a predetermined amount of free space is unavailable in the non-volatile memory to accommodate the new data or new discardable content;

subdividing at least one of the plurality of discardable data objects into new discardable data objects;

arranging a list of the discardable data objects and new discardable data objects for automatic deletion, the arranged list having an order based on respective discarding priority data; and

deleting discardable data objects or new discardable data objects in the arranged list sufficient to achieve the predetermined amount of free space.

18. The method of claim 17, wherein associating each discardable data object with discarding priority data comprises associating at least one discardable data object of the content with different discarding priority data than discarding priority data of a discardable data object of different content.

19. The method of claim 17, further comprising updating an existing discarding priority data of at least one discardable data object.

20. The method of claim 19, wherein associating each discardable data object with a discarding priority data comprises assigning a first of a sequence of discardable data objects of the discardable content discarding priority data such that the first of the sequence has a lower likelihood of deletion than any remaining discardable data objects of the content.

21. The method of claim 19, where updating the existing discarding priority data comprises updating the existing discarding priority data with different discarding priority data than that of another discardable data object of the content.

22. The method of claim 21, wherein updating the existing discarding priority data of at least one discardable data object comprises changing the existing discarding priority data based on at least one dynamic priority criteria determined when the at least one discardable data object is accessed.

23. The method of claim 22, wherein the at least one dynamic priority criteria comprises a time of last access of the discardable data object.

24. The method of claim 17, wherein deleting the amount of discardable data objects comprises selectively deleting, based on respective discarding priority data for the discardable data objects, one or more discardable data objects without deleting all discardable data objects for the content in order to free space in the non-volatile memory.

25. The method of claim 17, wherein deleting the amount of discardable data objects comprises selectively deleting one or more discardable data objects of a first content, without deleting all discardable data objects for the first content, in response to receipt of another content wherein a number of discardable data objects of different content is maximized.

26. A memory system for managing data received from a host, the memory system comprising:

a non-volatile memory; and

a processor operatively coupled to the non-volatile memory, wherein the processor is configured to;

receive a request to store at least a portion of content in the non-volatile memory;

divide the at least a portion of the content into a plurality of discardable data objects;

associate each discardable data object with discarding priority data; and

receive a request to store new data or new discardable content and, when a predetermined amount of free space is unavailable in the non-volatile memory to accommodate the new data or new discardable content;

subdivide at least one discardable data object into new discardable data objects;

arrange a list of the discardable data objects and new discardable data objects for automatic deletion having an order based on respective discarding priority data; and

delete discardable data objects or new discardable data objects in the arranged list sufficient to achieve the predetermined amount of free space.

27. The memory system of claim 26, wherein the processor is configured to associate at least one discardable data object of the content with different discarding priority data than the discarding priority data of another discardable data object of the content.

28. The memory system of claim 27, wherein the processor is configured to associate a first of a sequence of discardable data objects of the content with discarding priority data such that the first of the sequence has a lower likelihood of deletion than any remaining discardable data objects of the content.

29. The memory system of claim 26, wherein the processor is configured to update existing discarding priority data of at least one discardable data object.

30. The memory system of claim 29, wherein the processor is configured to update existing discarding priority data based on at least one dynamic priority criteria determined when the at least one discardable data object is accessed.

31. The memory system of claim 30, wherein the at least one dynamic priority criteria comprises an age of the discardable data object.

32. The memory system of claim 26, wherein the processor is configured to maximize a number of discardable data objects of different contents.