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Hello Stefan,<br>
<br>
The changes look good! Thanks for implementing this enhancement.<br>
<br>
One observation:<br>
gcArguments.cpp: if we use <span class="new">VerifyGCType with</span>
the collectors that currently don't support it, passing it multiple
comma separated strings, then parse_verification_type() will print
this warning message <span class="new">"VerifyGCType is not
supported by this collector." for all the strings. </span><span
class="changed">It would be better to break out from the while
loop in post_heap_initialize() if the collector does not support
this option.<br>
<br>
</span>Thanks,<br>
Poonam<br>
<br>
<div class="moz-cite-prefix">On 11/28/2017 8:25 AM, Stefan Johansson
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:2319511b-8979-92b9-34f2-6a4c1af46ebf@oracle.com">Hi,
<br>
<br>
Please review this change for enhancement:
<br>
<a class="moz-txt-link-freetext" href="https://bugs.openjdk.java.net/browse/JDK-8191821">https://bugs.openjdk.java.net/browse/JDK-8191821</a>
<br>
<br>
Webrev:
<br>
<a class="moz-txt-link-freetext" href="http://cr.openjdk.java.net/~sjohanss/8191821/00/">http://cr.openjdk.java.net/~sjohanss/8191821/00/</a>
<br>
<br>
Summary:
<br>
Heap verification is a very good way to track down GC bugs, but it
comes with a lot of overhead. Using VerifyBeforeGC, VerifyDuringGC
and VerifyAfterGC often slows down the execution more than is
needed since we sometimes only want to verify certain types of
GCs. This change adds this feature for G1 by adding a new
diagnostic flag VerifyGCType. The new flag currently only works
with G1 but can easily be added for more GCs if needed. The type
of the flag is ccstrlist which means the option can be used
multiple times to allow more than one type to be verified. The
types available for G1 is, young, mixed, remark, cleanup and full.
If the flag is not specified all GCs are verified.
<br>
<br>
Note that Verify/Before/After/During/GC is still needed to decide
what to verify, VerifyGCType only describes when.
<br>
<br>
Testing:
<br>
* Added new Gtest for G1HeapVerifier functionality.
<br>
* Added new Jtreg test for basic command line functionality.
<br>
* Executed Jtreg tests through mach5 to make sure it passes on all
platforms.
<br>
<br>
Thanks,
<br>
Stefan
<br>
</blockquote>
<br>
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