Methods and mechanisms for proactive memory management

• US 8,539,186 B2
• Filed: 04/13/2010
• Issued: 09/17/2013
• Est. Priority Date: 10/04/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Sechrest, Stuart, Fortin, Michael R., Iyigun, Mehmet, Ergan, Cenk
• Primary Examiner(s): THAI, TUAN V
• Application Number:
  US12/759,536
• Publication Number:
  US 20100199043A1
• Time in Patent Office: 1,253 Days
• Field of Search: 711/100, 711/154, 711/158, 711/165
• US Class Current: 711/165
• CPC Class Codes: G06F 12/121 using replacement algorithms
• CPC Class Codes: G06F 12/122 of the least frequently used [LFU] type, e.g. with individual count value

Abstract

A proactive, resilient and self-tuning memory management system and method that result in actual and perceived performance improvements in memory management, by loading and maintaining data that is likely to be needed into memory, before the data is actually needed. The system includes mechanisms directed towards historical memory usage monitoring, memory usage analysis, refreshing memory with highly-valued (e.g., highly utilized) pages, I/O pre-fetching efficiency, and aggressive disk management. Based on the memory usage information, pages are prioritized with relative values, and mechanisms work to pre-fetch and/or maintain the more valuable pages in memory. Pages are pre-fetched and maintained in a prioritized standby page set that includes a number of subsets, by which more valuable pages remain in memory over less valuable pages. Valuable data that is paged out may be automatically brought back, in a resilient manner. Benefits include significantly reducing or even eliminating disk I/O due to memory page faults.

Claims

1. A computer-readable storage device having stored thereon a data structure, comprising:

a standby page set for logically storing a plurality of pages of memory that have been identified as candidates for being paged out from system memory to durable storage due to memory pressure; and

a plurality of subsets in the standby page set, each subset being associated with a different priority value, each subset containing one or more of the pages having the priority value that is associated with the subset,

wherein the standby page set is rebalanced to move pages between the subsets based on measured usage information for the pages.

2. The computer-readable storage device of claim 1, wherein the standby page set includes at least one frequency-based subset in the standby page set for storing pages according to how often the page has been accessed.

3. The computer-readable storage device of claim 1, wherein the standby page set includes at least one time-of-last-usage-based subset in the standby page set for storing pages according to how recently the page has been accessed.

4. The computer-readable storage device of claim 1, wherein the standby page set includes at least one frequency-based subset in the standby page set for storing pages according to how often the page has been accessed, and at least one time-of-last-usage-based subset in the standby page set for storing pages according to how recently the page has been accessed, the standby page set rebalanced to move pages between the time-of-last-usage based subset and the frequency-based subset based on time data.

5. The computer-readable storage device of claim 1, wherein the standby page set includes a plurality of frequency-based subsets in the standby page set, the standby page set rebalanced to move pages between the frequency-based subsets based on time data.

6. The computer-readable storage device of claim 5, wherein at least one of the frequency-based subsets corresponds to a usage count per time period.

7. The computer-readable storage device of claim 6, wherein at least one other of the frequency-based subsets corresponds to a usage count per another time period.

8. The computer-readable storage device of claim 7, wherein the time periods are not equal in length.

9. The computer-readable storage device of claim 1, wherein the standby page set includes a plurality of time-of-last-usage-based subsets in the standby page set, the standby page set rebalanced to move pages between the time-of-last-usage-based subsets based on time data.

10. The computer-readable storage device of claim 1, wherein at least one of the subsets is present in the standby page set to fill with pages that are pre-fetched from a secondary storage device.

11. The computer-readable storage device of claim 1, wherein at least one of the subsets is present in the standby page set for storing pages that are locked into memory.

12. The computer-readable storage device of claim 1, wherein at least one of the subsets is present in the standby page set stores pages that have no associated score.

13. A computer-readable storage device having stored thereon a data structure, comprising:

a standby page set for logically storing pages of memory;

a plurality of subsets in the standby page set, each subset corresponding to a value associated with the pages therein; and

wherein the standby page set is rebalanced to move pages between the subsets based on measured usage information for the pages, and

wherein the standby page set includes a plurality of frequency-based subsets in the standby page set, the standby page set rebalanced to move pages between the frequency-based subsets based on time data.

14. The computer-readable storage device of claim 13, wherein the standby page set includes at least one time-of-last-usage-based subset in the standby page set for storing pages according to how recently the page has been accessed.

15. The computer-readable storage device of claim 13, wherein at least one of the frequency-based subsets corresponds to a usage count per time period.

16. The computer-readable storage device of claim 15, wherein at least one other of the frequency-based subsets corresponds to a usage count per another time period.

17. The computer-readable storage device of claim 16, wherein the time periods are not equal in length.

18. A computer-readable storage device having stored thereon a data structure, comprising:

a standby page set for logically storing pages of memory;

a plurality of subsets in the standby page set, each subset corresponding to a value associated with the pages therein; and

wherein the standby page set is rebalanced to move pages between the subsets based on measured usage information for the pages, and

wherein the standby page set includes a plurality of time-of-last-usage-based subsets in the standby page set, the standby page set rebalanced to move pages between the time-of-last-usage-based subsets based on time data.

19. The computer-readable storage device of claim 18, wherein the standby page set includes at least one frequency-based subset in the standby page set for storing pages according to how often the page has been accessed.

20. The computer-readable storage device of claim 18, wherein the standby page set includes at least one frequency-based subset in the standby page set for storing pages according to how often the page has been accessed, and at least one time-of-last-usage-based subset in the standby page set for storing pages according to how recently the page has been accessed, the standby page set rebalanced to move pages between the time-of-last-usage based subset and the frequency-based subset based on time data.