Request for review (S): 7037276: Unnecessary double traversal of dirty card windows

[Y. Srinivas Ramakrishna]

It's me again; looks like i got a couple of my repos
confused, and raised a false alarm. Please go ahead, continuing to
use the previous version of the webrev for your review.
Sorry for my confusion.

-- ramki

On 4/19/2011 7:28 PM, Y. Srinivas Ramakrishna wrote:
> I discovered a small flaw in this which I am going to fix.
> If you have not started your review yet, please hold off
> until I publish a second version of the changeset that
> fixes the flaw I found.
>
> Sorry for not having found this earlier and for the delay.
> -- ramki
>
> On 4/18/2011 11:34 AM, Y. Srinivas Ramakrishna wrote:
>>
>> I'd like a couple of code reviews for:
>>
>> 7037276: Unnecessary double traversal of dirty card windows
>> http://cr.openjdk.java.net/~ysr/7037276/webrev.00/
>>
>> Card scanning with ParNew and DefNew scavenges was collecting
>> dirty card windows in one method and then doing a retraversal
>> of that window in another method to clear the cards and iterate
>> over the refs on those cards. This double traversal was unnecessary,
>> since the collection of contiguous ranges, their clearing and the
>> iteration over the covered refs could all be done in a single sweep
>> over the cards covering the region of interest.
>>
>> I also specialized some of the arguments to these calls,
>> made some internal methods private and renamed a few others
>> for greater clarity.
>>
>> This is the second of a series of about 4 CRs aimed at eventually
>> fixing 6883834 (the last in the series). Stay tuned for some
>> more incremental rearrangements of related code in another
>> one or two subsequent CRs.
>>
>> A quick performance measurement didn't show any appreciable
>> change in scavenge times as a result of this change, but more
>> careful performance measurements are in progress.
>>
>> Tested with jprt, the test case for 6883834 and refworkload server.
>> Perf measurements with refworkload server in progress.
>>
>> thanks for your reviews.
>> -- ramki
>