Re: large files unnecessary trashing filesystem cache?

From: Ingo Oeser
Date: Thu Oct 20 2005 - 01:39:27 EST


Hi,

On Wednesday 19 October 2005 21:49, Andrew Morton wrote:
> Ingo Oeser <ioe-lkml@xxxxxxxxxx> wrote:
> > > > app which does setrlimit()+exec():
> > > >
> > > > limit-cache-usage -s 1000 my-fave-backup-program <args>
> > > >
> > > > Which will cause every file which my-fave-backup-program reads or writes to
> > > > be limited to a maximum pagecache residency of 1000 kbytes.
> > >
> > > Or make it another 'ulimit' parameter...
> > Which is already there: There is an ulimit for "maximum RSS",
> > which is at least a superset of "maximum pagecache residency".
>
> RSS is a quite separate concept from pagecache.

Yes I know, but the amount of pagecache which is RESIDENT for a process
is not that seperate from RSS, I think.

I always thought RSS is the amount of mapped and anonymous
pages of a process, which are in physical memory (aka resident).

So I consider the amount of mapped pagecache pages of
a process which are in physical memory (aka resident) a subset.

Or do you care about page cache pages not mapped into the process?
Is this the point I miss?

Please enlighten me :-)


Regards

Ingo Oeser

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