METHODS AND MECHANISMS FOR PROACTIVE MEMORY MANAGEMENT

• US 20100199043A1
• Filed: 04/13/2010
• Published: 08/05/2010
• Est. Priority Date: 10/04/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Fortin, Michael R., Ergan, Cenk, Iyigun, Mehmet, Sechrest, Stuart
• Granted Patent: US 8,539,186 B2
• Time in Patent Office: Days
• US Class Current: 711/118
• 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 medium 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

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

2. The data structure 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 data structure 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 data structure 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 data structure 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 data structure of claim 5 wherein at least one of the frequency-based subsets corresponds to a usage count per time period.

7. The data structure of claim 6 wherein at least one other of the frequency-based subsets corresponds to a usage count per another time period.

8. The data structure of claim 7 wherein the time periods are not equal in length.

9. The data structure 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 data structure 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 data structure 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 data structure of claim 1 wherein at least one of the subsets is present in the standby page set stores pages that have no associated score.