RFR: 8252921: NMT overwrite memory type for region assert when building dynamic archive

[Calvin Cheung]

On Tue, 15 Sep 2020 14:37:44 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> Thread stack is currently unregistered with NMT in Thread's destructor. Apparently, only Java thread invokes destructor
> before thread exits.  For NonJavaThread, e.g. ConcurrentGCThread, thread may exit while its "Thread" object continues
> alive, therefore, its thread stack is still "alive" from NMT perspective. Once thread exits, the virtual memory for the
> thread stack can be reserved again, that confused NMT.  The solution is to move thread stack unregistration code to
> post_run() method.

Thanks for the fix. I've done some testing on the patch. It passed tier1 and also passed running the
appcds/dynamicArchive/methodHandles/MethodHandlesAsCollectorTest.java test 30 times on Windows and linux. One question
: why the JavaThread::post_run doesn't need to set the following?
   set_stack_base(NULL);
   set_stack_size(0);

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Marked as reviewed by ccheung (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/185