 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| • |
Past
experience may indicate future behavior
|
|
|
| • |
Perfect
LRU requires some form of timestamp to be
|
|
|
associated
with a PTE on every memory reference !!!
|
|
|
| • |
Counter
implementation
|
|
|
|
– |
Every
page entry has a counter; every time page is referenced
|
|
|
through
this entry, copy the clock into the counter.
|
|
|
|
– |
When
a page needs to be changed, look at the counters to
|
|
|
determine
which are to change
|
|
|
| • |
Stack
implementation – keep a stack of page numbers in a
|
|
double
link form:
|
|
|
|
– |
Page
referenced: move it to the top
|
|
|
|
– |
No
search for replacement
|
|
