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From Egor Pasko <egor.pa...@gmail.com>
Subject Re: [drlvm] Class unloading support
Date Thu, 26 Oct 2006 03:21:08 GMT
On the 0x20D day of Apache Harmony Geir Magnusson, Jr. wrote:
> Egor Pasko wrote:
> > On the 0x20C day of Apache Harmony Aleksey Ignatenko wrote:
> >> Hello all!
> >>
> >>
> >>
> >> As you probably know current version of harmony DRLVM has no class unloading
> >> support. This leads to the fact that some Java applications accumulate
> >> memory leaks leading to memory overflow and crashes.
> >>
> >> In this message I would like to describe two approaches for class unloading
> >> in DRLVM and propose to implement one of them as basic. Pros and cons for
> >> both approaches are presented below. Lets name these approaches:
> >>
> >>    1. Mark and scan based approach.
> >>    2. Automatic class unloading approach.
> > I am +1 to (2)=(Automatic class unloading approach). Do not like
> > stop-the-world. But it has 1 more "cons" -- JIT should change it's
> > devirtualizer
> > accordingly to the VTable change. Doable, of course.
> > BTW, is it reasonable to "compress" or "enumerate" references to
> > j.l.Class in each object to reduce the footprint? How many classes are
> > alive in heavy-duty applications? not very much probably.
> 
> What is your sense of "very much"?  IOW, how many would make you say,
> "yeah, that's a lot"

hm, 1/10 of the whole heap is probably very much :)

-- 
Egor Pasko, Intel Managed Runtime Division


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