RFR: 8076265: Simplify deal_with_reference

Bengt Rutisson bengt.rutisson at oracle.com
Wed Apr 8 09:17:16 UTC 2015

Hi Kim,

Latest webrev looks good to me. Thanks for doing this cleanup!

One minor nit. The comment for CMTask::is_below_finger() is not very 
useful in my view:

1103   // Helper for deal_with_reference().
1104   bool is_below_finger(HeapWord* objAddr, HeapWord* global_finger) 

I'd prefer to leave that out. I don't need to see a new webrev for that. 
And if you feel strongly that the comment should be there I'm fine with 
leaving it too.


On 2015-04-03 01:17, Kim Barrett wrote:
> On Apr 1, 2015, at 7:01 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
>> Some comments:
> Thanks for making me look at this a little bit harder; I found some
> further simplifications and improvements.
> Note that in the sequence of tests to decide whether to push the
> object onto the mark queue or not, I'm preserving the existing order
> of tests.  I didn't want to make a possibly performance impactful
> change to that order without data to motivate such a change.
>> - what is the "mark bit processor/processing" mentioned in the
>> comment?
> I changed to consistently use "mark bitmap scan", but the
> surrounding context in the comments has been substantially rewritten.
> Hopefully it is more clear now.
>> - would it be possible to make it explicit that we check whether we
>> have a current region first?
> I don't really want to introduce a new trivial helper function for
> this purpose, but I've left a comment indicating why _finger is being
> used for the check.
>> passed -> past (I think).
> Fixed.
>> - I do not really like an extra parameter ... just for logging ...
> Restructuring has eliminated the need for that.
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8076265
> New full webrev:
> http://cr.openjdk.java.net/~kbarrett/8076265/webrev.01/
> New incremental webrev:
> http://cr.openjdk.java.net/~kbarrett/8076265/webrev.01.incr/
> Testing:
> local RefWorkload with -XX:+UseG1GC
> local JTREG with -XX:+UseG1GC

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