Physical page tracking for handling overcommitted memory
A system for computer memory management that implements a memory pool table, the memory pool table including entries that describe a plurality of memory pools, each memory pool representing a group of memory pages related by common attributes; a per-page tracking table, each entry in the per-page tracking table used to related a memory page with a memory pool of the memory pool table; and processing circuitry to: scan each entry in the per-page tracking table and, for each entry: determine an amount of memory released if the memory page related with the entry is swapped; aggregate the amount of memory for the respective memory pool related with the memory page related with the entry in the per-page tracking table, to produce a per-pool memory aggregate; and output the per-pool memory aggregate for the memory pools related with the memory pages in the per-page tracking table.
1. A system for computer memory management, the system comprising:
a first memory device to store a memory pool table, the memory pool table including entries that describe a plurality of memory pools, each memory pool representing a group of memory pages related by common attributes;
a second memory device to store a per-page tracking table, each entry in the per-page tracking table to relate a memory page with a memory pool of the memory pool table; and
processing circuitry to:
scan each entry in the per-page tracking table and, for each entry:
determine an amount of memory released if the memory page related with the entry is swapped; and
aggregate the amount of memory for the respective memory pool related with the memory page related with the entry in the per-page tracking table, to produce a per-pool memory aggregate; and
output the per-pool memory aggregate for the memory pools related with the memory pages in the per-page tracking table.
2. The system of claim 1 , wherein the memory pages of the per-page tracking table are subject to a memory reduction technique.
3. The system of claim 2 , wherein the memory reduction technique includes memory data compression.
4. The system of claim 2 , wherein the memory reduction technique includes memory deduplication.
5. The system of claim 1 , wherein the processing circuitry is further to:
sort the per-pool memory aggregates for the memory pools from a highest value to a lowest value.
6. The system of claim 1 , wherein an entry in the memory pool table is to include a memory pool index and pool attributes.
7. The system of claim 6 , wherein the pool attributes is a bitmap used to define the pool attributes of the entry in the memory pool table.
8. The system of claim 7 , wherein the pool attributes is a four-bit bitmap used to define whether a particular memory pool is a user pool or kernel pool, shared or not, standby or active, and paged or not paged.
9. The system of claim 1 , wherein an entry in the per-page tracking table is to include a page index, a memory pool index, and page attributes.
10. The system of claim 9 , wherein the page attributes define whether a particular memory page is locked or unlocked.
11. The system of claim 10 , wherein, to scan each entry in the per-page tracking table, the processing circuitry is to:
determine the entry indicates that the related page is locked, and
discontinue further processing of the entry in response to the related page being locked.
12. The system of claim 1 , wherein to scan each entry in the per-page tracking table, the processing circuitry is to:
determine the entry is related with a memory pool of interest; and
discontinue further processing of the entry in response to the entry not being related with the memory pool of interest.
13. The system of claim 12 , wherein to determine the entry is related with the memory pool of interest, the processing circuitry is to evaluate a priority threshold against a memory pool priority.
14. The system of claim 13 , wherein the memory pool priority is calculated from memory pool attributes stored in the memory pool table.
15. The system of claim 12 , wherein, to determine the entry is related with the memory pool of interest, the processing circuitry is to determine whether the memory pool related with the entry in the per-page tracking table is in a list of memory pools to process.
16. The system of claim 15 , wherein the list of memory pools to process is provided to the processing circuitry from operating system software.
17. A method of computer memory management, the method comprising:
accessing a memory pool table, the memory pool table including entries that describe a plurality of memory pools, each memory pool representing a group of memory pages related by common attributes;
accessing a per-page tracking table, each entry in the per-page tracking table used to related a memory page with a memory pool of the memory pool table; and
scanning each entry in the per-page tracking table and, for each entry:
determining an amount of memory released if the memory page related with the entry is swapped; and
aggregating the amount of memory for the respective memory pool related with the memory page related with the entry in the per-page tracking table, to produce a per-pool memory aggregate; and
outputting the per-pool memory aggregate for the memory pools related with the memory pages in the per-page tracking table.
18. The method of claim 17 , wherein scanning each entry in the per-page tracking table comprises:
determining the entry is related with a memory pool of interest; and
discontinuing further processing of the entry in response to the entry not being related with the memory pool of interest.
19. The method of claim 18 , wherein determining the entry is related with the memory pool of interest comprises evaluating a priority threshold against a memory pool priority.
20. The method of claim 19 , wherein the memory pool priority is calculated from memory pool attributes stored in the memory pool table.