RFR (S): 8153170: Card Live Data does not correctly handle eager reclaim

Thomas Schatzl thomas.schatzl at oracle.com
Mon Apr 18 15:12:08 UTC 2016


Hi Kim,

On Thu, 2016-04-14 at 11:09 -0400, Kim Barrett wrote:
> > On Apr 14, 2016, at 6:08 AM, Thomas Schatzl <
> > thomas.schatzl at oracle.com> wrote:
> > 
> > On Thu, 2016-04-14 at 00:31 -0400, Kim Barrett wrote:
> > > My one concern is that I'm having trouble figuring out when a 
> > > heap region might have reset_gc_time_stamp called on it.  Can 
> > > that happen in such a way that it would interfere with the use of 
> > > the time_stamp being added by these changes?  I will continue to 
> > > study, but maybe you already know and can provide guidance.
> > 
> > I do not think so.
> > 
> > Global reset_gc_time_stamp() (reset_gc_time_stamp() called on
> > G1CollectedHeap and all regions) is called during full gc (which 
> > aborts getting live data anyway), and at the end of the cleanup 
> > pause, after finalizing live data.
> > 
> > So the reset of the gc time stamps should be safe and not interfere
> > with this use.
> 
> Thanks, that agrees with / confirms what I was coming up with.
> 
> > New webrevs at
> > http://cr.openjdk.java.net/~tschatzl/8153170/webrev.0_to_1/ (diff)
> > http://cr.openjdk.java.net/~tschatzl/8153170/webrev.1/ (full)
> 
> Looks good.
> 
  thanks for your review.

Thomas


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