The following is what i read... The LRU lists include two kinds of pages: those belonging to the User Mode address spaces, and those included in the page cache that do not belong to any User Mode process. The PFRA should tend to shrink the page cache while leaving in RAM the pages owned by the User Mode processes. However, no fixed "golden rule" may yield good performance in every scenario, thus the refill_inactive_zone( ) function relies on a swap tendency heuristic value.
swap tendency = mapped ratio / 2 + distress + swappiness Here i am not understanding significance of swap tendency.And also they have given about "distress" as follow The distress value is a measure of how effectively the PFRA is reclaiming page frames in this zone; it is based on the scanning priority of the zone in the previous run of the PFRA, which is stored in the prev_priority field of the zone descriptor So here how "pre_priority" of zose is calculated... Thanks Shyam
