Patent ID: 7877570

Claim:
A computer implemented method, comprising: associating a first physical memory page with a first page table and a second physical page with a second page table, wherein the first page table comprises two bits to indicate a present access level and a previous access level of the first physical memory page; setting a first bit of the two bits to indicate that the present access level is a read only access level when the first physical memory page is being checked, wherein a second bit of the two bits indicates that the previous access level is set to a read only access level or a read and write access level; setting an examination bit to indicate that the first physical memory page is being checked; checking whether the first physical memory page matches the second physical memory page, wherein said checking comprises comparing the first physical memory page with the second physical memory page; and if the second physical memory page matches the first physical memory page, deallocating the second physical memory page, and associating the second page table with the first physical memory page.