On Thu, 18 Oct 2007 17:27:00 +1000
Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> Some filesystems, including I believe, ext3 with data=ordered,
> can leave orphaned pages around after they have been truncated
> out of the pagecache. These pages get left on the LRU and vmscan
> reclaims them pretty easily.

How can the VM recognize those pages?  Are they part of
the buffer cache, part of the page cache, or different?

I think it would make sense to at least try to rotate
those pages to the end of the LRU so kswapd can get rid
of them quickly.

-- 
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan