anonymous buffer pages

anonymous buffer pages

[Raghu R. Arur]

 Hi,

  when are anonymous buffer pages created and how are they removed from
the system  in linux 2.4.19 ? In try_to_swap_out() when it encounters a
anonymous buffer page the page is not unmapped from the process. So how is
this page freed to the free-list ?

 Thanks a lot,
Raghu
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Re: anonymous buffer pages

[Mel Gorman]

On Tue, 5 Aug 2003, Raghu R. Arur wrote:

>   when are anonymous buffer pages created and how are they removed from
> the system  in linux 2.4.19 ?

Buried in
http://www.skynet.ie/~mel/projects/vm/guide/html/understand/node70.html#SECTION001533000000000000000
is

"An anonymous page may have associated buffers if it is backed by a swap
file."

The reason being that the page will need to be written out in block-sized
chunks. Once written out, the page->buffers will be null again and it'll
be cleared out the normal way via the swap cache when all processes have
unmapped the page

-- 
Mel Gorman
http://www.csn.ul.ie/~mel
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