[R] Windows Memory Issues

[Prof Brian Ripley]

On Tue, 9 Dec 2003, Thomas Lumley wrote:

> On Tue, 9 Dec 2003 Benjamin.STABLER at odot.state.or.us wrote:
> 
> > Thanks for the reply.  So are you saying that multiple calls to gc() frees
> > up memory to Windows and then other processes can use that newly freed
> > memory?
> 
> No.  You typically can't free memory back to Windows (or many other OSes).

At least using R under Windows NT/2000/XP you can.  I've watched it do so 
whilst fixing memory leaks.

There is another complication here: R for Windows uses a third-party 
malloc, and you can free memory back to that if not to the OS.  The reason 
Windows is special is the issue of fragmentation, which OSes using mmap
(and R-devel under Windows) typically do not suffer.


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595