G1-GC - Full GC [humongous allocation request failed]

[Vitaly Davidovich]

On Monday, October 10, 2016, Thomas Schatzl <thomas.schatzl at oracle.com>
wrote:

> Hi,
>
> On Mon, 2016-10-10 at 06:45 -0400, Vitaly Davidovich wrote:
> >
> >
> > On Monday, October 10, 2016, Thomas Schatzl <thomas.schatzl at oracle.co
> <javascript:;>
> > m> wrote:
> > >
> > > On Mon, 2016-10-10 at 10:12 +0200, Thomas Schatzl wrote:
> > > > Hi all,
> > > >
> > > [...]
> > > >
> > > > (I am probably forgetting one or the other edge case here, but
> > > that's
> > > > the general idea; also please consider that for G1, except for
> > > > humongous allocations, the heap does not need to )
> > >
> > > ... the actually occupied heap area does not need to be contiguous.
> > > It's just easier to draw as such :)
> > Are the reserved regions contiguous or no?
>
>   no. You can't guarantee that. Consider long-living allocations into
> this area. At the moment G1 never moves humongous objects.

Yeah, I didn't expect them to be but wanted to clarify/confirm that.  This
makes them less useful for covering humongous allocations, but I understand
the constraints.  Also, by considering the reserve as a watermark value,
rather than space you really expect to use, I think that's fine.

Thanks

>
> Thomas
>
>

-- 
Sent from my phone
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-use/attachments/20161010/dcc38fdb/attachment-0001.html>