[fedora-java] Eclipse and JVM memory settings

[Andrew Haley]

Andrew Overholt writes:
 > Hi,
 > 
 > Now that we have people using Eclipse on IcedTea, we have people
 > starting to hit memory limits.  I don't understand the situation very
 > well, but here are some links to Eclipse bug reports, etc.:
 > 
 > http://www.eclipsezone.com/eclipse/forums/t101303.rhtml
 > 
 > http://wiki.eclipse.org/FAQ_How_do_I_increase_the_permgen_size_available_to_Eclipse%3F
 > 
 > https://bugs.eclipse.org/bugs/show_bug.cgi?id=195897
 >  - the Eclipse launcher (largely written in C) can tell if it's running
 >    on a Sun VM on Windows -- it looks like it reads .dll headers -- but
 >    not on Linux
 > 
 > I spoke briefly with Andrew Niefer and a few other people on IRC and
 > here are a few options for fixing the launcher to work with the -XX
 > options in both the Sun VM and non-Sun VM cases:
 > 
 >   1. try starting the VM using the invocation api (using libjvm.so) with
 >      the PermSize argument and see if it fails - if it does, launch
 >      without the option.  This may add some startup delay to VMs that
 >      don't support this option.  This was suggested in the eclipse.org
 >      bug I link to above.

I presume that this space is mapped at startup and never resized,
which is why it's a problem.  Mapped (but never used) memory on Linux
only takes up address space, not real memory, so we could simply make
the default permgen bigger on IcedTea.  This problem would simply go
away, at no significant cost to anyone.

Andrew.

-- 
Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, UK
Registered in England and Wales No. 3798903