Virtual Memory Page Replacement
When the Running process requests a page that is not in memory,
a page fault results,
and (if the memory is currently 'full')
one of the frames currently in memory must be replaced by the required page.
To make room for the required page,
one or more existing pages must be "evicted" (to the swap space).
Clearly, the working set of some process must be reduced.
However, if a page is evicted just before
it is required (again),
it'll just need to be paged back in!
If this continues, the activity of page thrashing is observed.
We hope that the operating system can avoid thrashing with an intelligent
choice of the page to discard.
CITS2002 Systems Programming, Lecture 14, p6, 12th September 2023.
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CITS2002