Re: vmscan.c heuristic adjustment for smaller systems

From: Andrew Morton
Date: Sun Apr 18 2004 - 00:54:21 EST

Marc Singer <elf@xxxxxxxxx> wrote:
> On Sat, Apr 17, 2004 at 08:53:38PM -0700, Andrew Morton wrote:
> > William Lee Irwin III <wli@xxxxxxxxxxxxxx> wrote:
> > >
> > > On Sat, Apr 17, 2004 at 04:51:51PM -0700, Andrew Morton wrote:
> > > > I'd assume that setting swappiness to zero simply means that you still have
> > > > all of your libc in pagecache when running ls.
> > > > What happens if you do the big file copy, then run `sync', then do the ls?
> > > > Have you experimented with the NFS mount options? v2? UDP?
> > >
> > > I wonder if the ptep_test_and_clear_young() TLB flushing is related.
> >
> > That, or page_referenced() always returns true on this ARM implementation
> > or some such silliness. Everything here points at the VM being unable to
> > reclaim that clean pagecache.
> How can I tell?

Well some more descriptions of what the system does after that copy-to-nfs
would help. Does it _ever_ come good, or is a reboot needed, etc?

What does `vmstat 1' say during the copy, and during the ls?

/proc/vmstats before and after the ls.

Try doing the copy, then when it has finished do the old
memset(malloc(24M)) and monitor the `vmstat 1' output while it runs,
capture /proc/meminfo before and after.

None of the problems you report are present on x86 as far as I can tell,

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