RFR: JDK-8204685: Abstraction for TLAB dummy object

[Thomas Schatzl]

Hi,

On Tue, 2018-06-12 at 18:40 +0200, Roman Kennke wrote:
> Am 12.06.2018 um 15:58 schrieb Aleksey Shipilev:
> > On 06/11/2018 06:02 PM, Roman Kennke wrote:
> > > Similar to how object allocations should be owned by the GC, so
> > > does TLAB dummy object 'allocation'. TLABs and PLABs are filling
> > > their remaining blocks with dummy objects. GCs like Shenandoah
> > > might need a slightly different layout for this, and therefore we
> > > need an abstraction.
> > > 
> > > The proposed change adds a new virtual method
> > > CollectedHeap::fill_with_dummy_object(), the default
> > > implementation calls the existing CH::fill_with_object() from
> > > TLAB and PLAB like it was done before.
> > > 
> > > Tested: hotspot-tier1, Shenandoah tests with appropriate impl
> > > 
> > > http://cr.openjdk.java.net/~rkennke/JDK-8204685/webrev.00/
> > 
> > I have doubts about setting "zap = false" unconditionally. As far
> > as I can see, zapping is enabled
> > for debug builds only anyway, so we better keep it "true".
> > 
[...]
> 
> Right.
> http://cr.openjdk.java.net/~rkennke/JDK-8204685/webrev.01/
> 
> Good now?
> 

  good.

Thomas