Re: madvise on file pages

From: Antonio Vargas (wind@cocodriloo.com)
Date: Fri Aug 01 2003 - 16:39:53 EST


On Thu, Jul 31, 2003 at 03:32:11PM -0700, Andrew Morton wrote:
> "Muthian S" <muthian_s@hotmail.com> wrote:
> >
> > Hi,
> >
> > Could someone inform as to what is the behavior when madvise DONTNEED is
> > called on pages that are mmap'd from local files mapped with MAP_SHARED,
> > i.e. they share the same page that the file cache does.
>
> The pages are unmapped from the calling process's pagetables. We don't
> actually free the physical pages.
>
> > In such cases, can
> > madvise be made to release specific pages in the file cache by mmap-ing the
> > relevant file segment ?
>
> No.
>
> 2.6 kernels implement the fadvise() syscall (accessible by glibc's
> posix_fadvise() function) which will do this.

Perhaps we could send the page to the least-used end of the page lists?

-- 
winden/network

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