RFR: 8200429: Adjust object pinning interface on CollectedHeap

[David Holmes]

Hi Per,

On 3/04/2018 4:42 PM, Per Liden wrote:
> The recent additions to CollectedHeap to support object pinning didn't 
> quite fit the bill for what the Shenandoah folks had in mind. Instead of 
> having CollectedHeap::pin_obejct/unpin_object grab/release the GCLocker 
> when object pinning is not supported, we add a 
> CollectedHeap::supports_obejct_pinning() and let the caller take the 
> appropriate action based on the response.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8200429
> Webrev: http://cr.openjdk.java.net/~pliden/8200429/webrev.0

This looks fine to me. If we ever get a third way of not allowing an 
object to move we should probably try to think of a good name for that 
operation. ;-)

Thanks,
David

> /Per