Evicting Anonymous pages.

[Prateek Sharma]

Hello everyone,
  I am trying to understand the kernel page frame reclaiming
mechanism, but one thing's bothering me:
How does the kernel 'know' which anonymous pages to evict? In the LRU
scheme,  'referenced/used' information for each page is required
(AFAIK). But anonymous pages can be used by user processes 'at any
time' without the kernel knowing about it.

   Am i missing something? Or does the kernel just drop some random
anon pages of a process? Is there a way to obtain the 'referenced'
information about anonymous pages as well?

Thanks,
Prateek