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[20060216]
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Separating page replacement policy
If you have your flat already full of friends and another one arrives,
whom do you send out to fetch beer? There are many ways to decide,
and that problem is equivalent to the question of what piece of
main memory ("page") to write to secondary storage ("swap space")
so a program's need for more memory can be satisfied. There are many
theories on what to do (least recently used, ...) that are subject
to operating systems theory.
The implementation of the page replacement policy in NetBSD was
closely tied to the virtual memory system of NetBSD, uvm.
Now, Yamamoto Takashi has started work on seperating the page
replacement policy from the rest of the VM system, so different
policies can be used easily.
See
his first mail for pointers to code and patches, and
his second mail for more pointers on where to
find information on the actual algorithms used.
[Tags: kernel, uvm]
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