RFR(XXS): 8017070: G1: assert(_card_counts[card_num] <= G1ConcRSHotCardLimit) failed
john.cuthbertson at oracle.com
Fri Jun 28 20:27:49 UTC 2013
Thanks for the review.
On 6/28/2013 12:17 PM, Jon Masamitsu wrote:
> Looks good.
> On 6/28/2013 12:01 PM, John Cuthbertson wrote:
>> Hi All,
>> Can I couple of volunteers review this extremely small change? The
>> webrev can be found at:
>> The assert that fired is invalid. A card can be added to more than
>> one update buffer since reads and writes to the card table are not
>> atomic. If two threads end up refining the card at the same time then
>> the count for that card can be incremented twice. If count is just
>> below the hot threshold, the double increment will trip the assert.
>> Since the card was enqueued by two different threads we do want the
>> the double increment to more accurately reflect how hot the card is.
>> I have removed the invalid assert and use a bounding expression to
>> assign the new count value.
>> Weblogic+medrec on the failing SQE machine (though I couldn't
>> reproduce the original problem)
>> Weblogic+medrec on an Intel Haswell machine
>> GC test suite
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