Regarding LRU

["shyam Burkule" <shyam.burkule@xxxxxxxxx>]

  I am studing How memory management of linux works..Curruntly I am reading LRU policy.The following is what i know about how LRU approximation moves pages across its active and inactive list.

 

   LRU take help of some flags(like pg_references ) for deciding number of access..

   Now Suppose  a page is in the inactive list and has the PG_referenced flag set to 0. The first page access sets the value of the flag to 1, but the page remains in the inactive list. The second page access finds the flag set and causes the page to be moved in the active list. If, however, the second access does not occur within a given time interval after the first one, the page frame reclaiming algorithm may reset the PG_referenced flag.

   

 

      I am here  not understanding how this "time interval (time stamp )" is decided . And which part of the code does this functioning ..Is there any kernel thread that invokes periodically or what exactly done here ?

   Hope you Clerify this....This is very important for us plese help us..

 

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Thanks