RFR (S): 8154528: Reclaim regions emptied by marking in Remark pause

[Thomas Schatzl]

Hi,

  ping for a second reviewer....

Thomas

On Thu, 2018-03-29 at 16:49 +0200, Thomas Schatzl wrote:
> Hi all,
> 
>   can I have reviews for this change that moves the space reclamation
> of empty regions into the Remark pause, which makes these regions
> available much sooner than before, with the obvious benefits of doing
> so.
> 
> The Cleanup pause now only contains updating the remembered set
> states
> after rebuilding remembered sets and determining the collection set
> candidates. In the future we might be able to make those concurrent
> and
> drop the Cleanup pause completely.
> 
> There is not much too say here, after all the recent refactorings
> this
> patch is almost trivial :)
> 
> From a timing POV this adds a few ms to the Remark pause in my
> measurements, mostly from the code root purging moved here. I think
> there is enough opportunity in the remark pause to decrease its
> duration in the future that outweighs the mentioned benefits.
> 
> Thanks go to everyone reviewing so far, particularly StefanJ and
> Sangheon!
> 
> Depends on JDK-8178105.
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8154528
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8154528/webrev/
> Testing:
> hs-tier 1-5
> 
> Thanks,
>   Thomas
> 
> 
>