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From: gringort@wsl.dec.com (Joel Gringorten)
Newsgroups: comp.unix.ultrix
Subject: Re: Xcfb growing and growing and grow....
Message-ID: <1991Jan25.170335@wsl.dec.com>
Date: 26 Jan 91 01:03:35 GMT
References: <2383@aerodec.anu.edu.au> <15990@crdgw1.crd.ge.com> <1474@mpirbn.mpifr-bonn.mpg.de>
Sender: news@pa.dec.com (News)
Reply-To: gringort@wsl.dec.com (Joel Gringorten)
Organization: DEC Western Software Lab
Lines: 24

I'm suprised that nobody's pointed this out yet, but...

All X Servers have a tendancy to grow.  They allocate storage for a variety
of reasons resulting from client requests.  When this allocated storage is
free'd, the process doesn't grow any smaller.  So the server process size can 
only grow larger and not smaller.  There are some versions of Unix that can
do a negative sbrk, but this only works if you happen to have contiguous 
address space at the end of your process.  Fragmentation of the allocated 
storage space makes this less likely.  

The virtual address size (SIZE) of the server isn't particularly interesting 
anyway. What's interesting is the resident set size (RSS) which tells you how
much memory you're really hogging.  

Many X Servers, including DEC's, have memory leaks which will cause them to
hog more memory than they should.  DEC has been religous about tracking down
memory leaks in their servers over time.  This is to say that the more recent
the release, the fewer memory leaks a server is likely to have.  The next 
release of Ultrix will contain a server based on MIT X11R4, which uses much
less memory than previous releases due to reorganizing internal data structures.
But even it will have a tendancy to grow in virtual address space in time.  It's
just the nature of the beast.  

-joel