7172708: 32/64 bit type issues on Windows

Alan Bateman Alan.Bateman at oracle.com
Wed Jun 6 04:07:30 PDT 2012

On 06/06/2012 02:22, David Holmes wrote:
> Presently hotspot does, simply because a 64-bit value is assigned to a 
> 32-bit variable. Other than that hotspot doesn't even look at the 
> value of this flag. We would have to change that to sanity check its 
> range.
I think we should at least change it so that it's not truncated to a 
32-bit signed value, that way we can at least specify the limit >=2GB on 
32-bit. I would be tempted to leave any additional sanity checking to 
sun.misc.VM. There are cases today where people are running with the 
limit >=4GB on 64-bit systems (although I haven't seen it on Windows 
where the original issue was reported).

> A value of -1 means "use the default".
Yes, currently it's treated by use-default and the question is whether 
we should just leave it as is or change it. The only argument for 
changing it is that it's an inconsistent from a user perspective when 
compared with options such as MaxHeapSize where it's a fatal error to 
attempt to start with it on the command line to -1. On the other hand it 
is possible that someone might be specify MaxDirectoryMemorySize=-1 
today, and I can't think why anyone would do that so it may be safer to 
just leave it as is.


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