request for review (XS): 6916968 CMS: freeList.cpp:304 assert(_allocation_stats.prevSweep() + ..., "Conservation Principle")

[Y. Srinivas Ramakrishna]

6916968 CMS: freeList.cpp:304 assert(_allocation_stats.prevSweep() + ..., "Conservation Principle")

The conservation principle had been incorrectly formulated, with at least one
production factor missing. This also necessitated a change in the demand
computation which was similarly missing a production factor and thus
slightly underestimating demand. Since "coalBirths" are rare in practice
(except during sweeps which this does not count) this change has minimal
effect on demand estimates, and also explains why it was violated so rarely.
The correction also allowed us to reenable an assert that we had disabled
before, but i left in a defensive floor on the demand computation in the
event that our counting is still imprecise because of inadvertently
missing certain birth or death events.

webrev: http://cr.openjdk.java.net/~ysr/6916968/webrev.0/

testing: refworkload (will be run to verify the expectation of no appreciable change
          in demand estimates following this correction), jprt,
          the gcl001 gclocker test which had recently started failing somewhat regularly in nightly 
testing),
          the largeObject tests that had failed the assert in the distant past

thanks for your reviews.
-- ramki