Method to improve page out mechanism with compressed memory pools
View Patent ↗A method for setting a compression ratio for utilizing a compressed memory pool (which is backed by pinned memory) by a virtual memory manager (VMM). Compression of pages of corresponding segments can be tracked as part of a VMM paging algorithm that compresses pages to store in a compressed memory pool. A segment having pages with an average compression ratio below a threshold is identified. The identified segment pages are prevented from utilizing the compressed memory pool resulting in optimizing the use of the compressed memory pool.
1. A method for setting a compression ratio for utilizing compressed memory by a virtual memory manager (VMM), comprising:
tracking compression of pages of corresponding segments as part of a VMM paging algorithm that compresses pages to store in a compressed memory pool;
identifying a segment having pages with a compression ratio below a threshold;
preventing the identified segment pages from utilizing the compressed memory pool;
sending the identified segment pages to disk paging space;
sending the non-identified segment pages having a compression ratio meeting or exceeding the threshold to the compressed memory pool;
specifying an amount of pages in the segment to page-out to the compressed memory pool, wherein the specified amount of pages is at least five percent of a total number of pages in the segment, and the amount of pages in the segment to page-out being less than a total amount of pages of the segment;
after the specifying of the amount of pages in the segment to page-out, calculating the compression ratio based on the paged-out pages of the segment by:
calculating an average compression ratio of the pages based on the paged-out pages of the segment;
marking the segment as uncompressible when the specified amount of pages have an average compression ratio below the threshold;
marking the segment as compressible when the specified amount of pages have an average compression ratio meeting or exceed the threshold;
determining when a memory threshold is met for the compressed memory pool which indicates that the compressed memory pool cannot accept pages for compression, and determining the memory threshold not being met which indicates that the compressed memory pool can accept pages for compression;
sending the pages of the segment marked uncompressible to the disk paging space when either the memory threshold is met and when the memory threshold is not met, thereby always sending the pages of the segment marked uncompressible to the disk paging space; and
sending the pages of the segment marked compressible to the compressed memory pool when the memory threshold has not been met.
2. The method of claim 1 , wherein the threshold compression ratio is fifty percent compressibility for the pages.