Re: userspace pagecache management tool

Andrew Morton
2007-03-07T18:50:59Z

On Wed, 07 Mar 2007 11:39:02 +0000 Pádraig Brady <P@draigBrady.com> wrote:

> Andrew Morton wrote:
> > On Tue, 06 Mar 2007 12:10:49 +0000
> > P__draig Brady <P@draigBrady.com> wrote:
> >> Perhaps one could possibly just evict pages with _mapcount==0 ?
> >
> > That is the present fadvise(FADV_DONTNEED) behaviour.
>
> Ah right. It doesn't invalidate page_mapped() pages.

yup

> If that means it doesn't invalidate pages previously cached
> by other processes, then great.

It will do that. This is why I point out that this userspace tool
could (easily) be enhanced to not invalidate pages which were
in pagecache prior to their being read by the managed application.