RFR: 8252921: NMT overwrite memory type for region assert when building dynamic archive [v5]

[David Holmes]

On Sun, 20 Sep 2020 23:09:20 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.
>
> Zhengyu Gu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix metaspace remapping on Windows

Changes requested by dholmes (Reviewer).

src/hotspot/share/runtime/thread.cpp line 1341:

> 1339:   unregister_thread_stack_with_NMT();
> 1340:   set_stack_base(NULL);
> 1341:   set_stack_size(0);

Sorry but I just don't see any need for clearing stack_base or stack_size, and then you don't need to mess with the
assertion in stack_base().

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