Re: inode_cache / dentry_cache not being reclaimed aggressively enough on low-memory PCs

[Marcelo Tosatti <marcelo.tosatti@cyclades.com>]

On Sat, 3 Jan 2004, Mike Fedyk wrote:

> On Sat, Jan 03, 2004 at 07:05:43PM -0800, Andrew Morton wrote:
> > Alex Buell <alex.buell@munted.org.uk> wrote:
> > >
> > > On Sat, 3 Jan 2004, Andrew Morton wrote:
> > >
> > > > John Lash <jlash@speakeasy.net> wrote:
> > > > >
> > > > > As it stands, it will maintain as many unused entries as there are used entries.
> > > > >  If this low memory system las a large, stable, number of inuse dentry objects,
> > > > >  the unused entries will match it thereby holding double the memory and possibly
> > > > >  causing the problem you see.
> > > >
> > > > Yup.   There is a fix in 2.6.1-rc1 for this.
> > >
> > > Which change would that be? It would be nice to back-port that to 2.4.x if
> > > that's possible?
> >
> > It is not backportable.
> >
> > You could try increasing `count' in shrink_dcache_memory() and
> > shrink_icache_memory().  Also you should be using 2.4.23 or later because
> > it does have improvements in the memory reclaim area.
>
> Also, if there are any improvements considered for the 2.4 VM, it should be
> on top of the -aa series.  That's where the latest updates are, and it
> doesn't make sence to work from a base that already has seperate
> improvements available.

The fix in -aa seems to reclaim inodes very aggressively. The 2.4 RH tree
seems to contain a better version. Need to look into that.