Virtual machine manager initiated page-in of kernel pages

Abstract

A rule-based method for pre-fetching “important pages” from memory paging space back into kernel memory space performs the following steps: (i) establishing a first machine logic based rule, with the machine logic based rule including a first triggering condition and a first consequential responsive action; (ii) determining that the first triggering condition has occurred; and (iii) in response to the determination that the first triggering condition has occurred, performing the first consequential responsive action. The first triggering condition includes the following sub-conditions: (i) at least one of a first set of important page(s) of a computer system has been paged out of kernel memory space and into paging memory space, and (ii) a processing status of the computer system indicates that the first set of important page(s) will be likely to be required for computer operations.

What is claimed is: 
     
         1 . A method comprising:
 establishing a first machine logic based rule, with the machine logic based rule including a first triggering condition, a first consequential responsive action, a second triggering condition, a second consequential responsive action, a third triggering condition, a third consequential responsive action, a fourth triggering condition, a fourth consequential responsive action;   determining that the first triggering condition has occurred;   in response to the determination that the first triggering condition has occurred, performing the first consequential responsive action;   determining that the second triggering condition has occurred;   in response to the determination that the second triggering condition has occurred, performing the second consequential responsive action;   determining that the third triggering condition has occurred;   in response to the determination that the third triggering condition has occurred, performing the third consequential responsive action;   determining that the fourth triggering condition has occurred;   in response to the determination that the fourth triggering condition has occurred, performing the fourth consequential responsive action;   wherein:   the first triggering condition includes the following sub-conditions:
 (i) at least one of a first set of important page(s) of a computer system has been paged out of kernel memory space and paged into paging memory space, and 
 (ii) a processing status of the computer system indicates that the first set of important page(s) will be likely to be required for computer operations; and 
   the first consequential responsive action includes the following:
 for any important page of the first set of important page(s) not present in kernel memory space, paging that important page from paging memory space back into kernel memory space; 
   the second triggering condition further includes the following sub-condition(s):
 at least one backtrack exception is generated during page fault on behalf of at least one of the following sub-systems: virtual machine monitor (VMM), page size management daemon (PSMD), and/or least recently used daemon (LRUD); 
   the second consequential responsive action includes the following:
 for any important page of the first set of important page(s) not present in kernel memory space, paging that important page from paging memory space back into kernel memory space; 
   the third triggering condition further includes the following sub-conditions:
 at least one backtrack exception is generated during page fault on behalf of device drivers and/or kernel extensions that are registered with a virtual machine monitor (VMM) sub-system; 
   the third consequential responsive action includes the following:
 for any important page of the first set of important page(s) not present in kernel memory space, paging that important page from paging memory space back into kernel memory space; 
   the fourth triggering condition further includes the following sub-conditions:
 LRU critical code is executed when a free page count drops below a predetermined minimum free threshold; and 
   the fourth consequential responsive action includes the following:
 for any important page of the first set of important page(s) not present in kernel memory space, paging that important page from paging memory space back into kernel memory space.