Any new ideas on JDK-8187338 (Per anonymous class class loader data is costly)?

[Thomas Stüfe]

On Fri, Nov 24, 2017 at 10:29 AM, Andrew Dinn <adinn at redhat.com> wrote:

> One small additional comment:
>
> On 24/11/17 09:18, Andrew Dinn wrote:
> > On 23/11/17 20:43, Thomas Stüfe wrote:
> >> ...
> >> Well, this sounds both simpler and more to the point than my proposal
> (2).
> >
> > Not quite. We know that the "half-eaten-medium-chunk" problem is really
> > a bad problem for anonymous class loaders and Zhengyu's patch improves
> > that case. We don't know it is that is the only problem case. Other
> > loaders may only load a small number of classes -- perhaps 1, maybe 2 --
> > and also end up wasting a lot of space. If an app hits that case a lot
> > then your proposal would allow the user to configure round it.
> n.b. I'm not sure we need to worry much about any such apps as this
> scenario is, arguably, very unlikely? I know, for example, that JBoss
> Modules uses many classloaders but they rarely load just one or two
> classes. Once you get to 3 or 4 classes I think the current behaviour
> will be unlikely to increase waste because larger chunks means less
> fragmentation. Are OSGi loaders likely to load just one or two classes
> for a significant number of loaders?
>
>
I do not think so. I think you are right, this is less pressing once we get
Zhengyus patch.
I will add the switch when there is some time, I still think it may be good
to have.

Kind Regards, Thomas


> regards,
>
>
> Andrew Dinn
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