Rik van Riel's Talk [LWN.net]

Rik van Riel's Talk

Posted Jul 29, 2003 6:08 UTC (Tue) by walters (subscriber, #7396)
In reply to: Rik van Riel's Talk by tjc
Parent article: Trip report: the Ottawa Linux Symposium

Does the JVM walk through it's entire virtual address space, or does it just visit pages that have been marked in some way? The former would be horrible, but I'm not sure the later is possible on most architectures.

Neither. Most of them only traverse allocated objects, looking at pointers. But I think what Rik is talking about is that this may end up hitting the majority of pages allocated. See any paper on garbage collection for more information.

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Rik van Riel's Talk

Posted Jul 29, 2003 8:49 UTC (Tue) by dancres (guest, #4360) [Link]

I tend to agree but the number of objects traversed at any point is also dependent on the algorithm chosen. Certain types of GC will be far worse in respect of this behaviour than others.

I'd sure be interested in hearing Rik "name and shame" the various VM implementations.

Rik van Riel's Talk

Posted Jul 30, 2003 20:06 UTC (Wed) by stuart2048 (subscriber, #6241) [Link]

For years I have dreamt of a Java environment that, instead of
relying on the OS to blindly manage pages, integrates the paging
system directly into the object heap. So that the Java VM pages
objects, or parts of objects that aren't being used (but are
not quite garbage yet).

Of course I expect some of you will tell me this was implemented
30 years ago in some other language ;-)