RFR(S): 8058251 - assert(_count > 0) failed: Negative counter when running runtime/NMT/MallocTrackingVerify.java

[Christian Tornqvist]

Hi everyone,

 

Fairly small change which fixes one of the instances of assert(count > 0),
the issue was that the mallocSiteTable became full, NMT changed from detail
to summary but never updated the tracking level field in the malloc header.
Since the malloc was never inserted into the mallocSiteTable we didn't
update the bucket and position in the malloc header and when we later on was
trying to free that memory block we found tracking level == detailed and
used the never initialized fields for bucket and position indexes. 

 

The only place that looked at the level field in the header was
MallocHeader::release and it could check the global level state instead. So
I removed the 2bit level  field from the malloc headers and this enabled me
to get rid of the 30bit malloc limitation on 32bit systems. 

 

Also fixed a sign conversion issue on 32bit platforms in WB API
NMTMallocWithPseudoStack.

 

Note that this fix doesn't solve all the sources for the assert and I'm not
going to enable the test at this point as we continue to track down the
additional issues.

 

The fix has been tested using jprt and aurora adhoc with NMT.

 

Webrev:

http://cr.openjdk.java.net/~ctornqvi/webrev/8058251/webrev.00/

 

Bug:

https://bugs.openjdk.java.net/browse/JDK-8058251

 

Thanks,

Christian