On Fri, Oct 19, 2012 at 11:31 AM, Chris Muller ma.chris.m@gmail.com wrote:

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I have an image which needed to allocate 500MB of memory for a large operation. Now that operation is done and all objects have been reclaimed. According to VM I am now only using 200MB.

(Smalltalk vmParameterAt: 2) max: (Smalltalk vmParameter at: 1) "221923374"

However, when I look at my VM process in "top" or the System Monitor, it still says its >500MB.

How does this work?

Depends on the platform. On Mac OS X memory is not returned. On Windows memory is allocated and freed via VirtualAlloc and VirtualFree. On Unix memory is allocated and returned via mmap and munmap by default. What OS are you on? Looks like the unix code could be ported to the Mac easily.

Linux chrisT520 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

So, after several hours top still shows >500MB. Will it ever go back down to the level reported by vm-parameters [1,2 or 3]?

I'm not sure. It all depends on the useMmap variable in the linux vm. If it is non-zero then a cursory reading of the source says that yes, the memory should be returned.