RFR: 8257831: Suspend with handshakes [v3]

[Robbin Ehn]

On Tue, 30 Mar 2021 20:27:46 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
>> 
>>  - Merge branch 'master' into SuspendInHandshake
>>  - Merge branch 'master' into SuspendInHandshake
>>  - 8257831: Suspend with handshake (review baseline)
>
> src/hotspot/share/runtime/sweeper.cpp line 276:
> 
>> 274: 
>> 275:     ThreadBlockInVM tbivm(thread);
>> 276:     thread->java_suspend_self();
> 
> In the baseline version of NMethodSweeper::handle_safepoint_request() there is a call `thread->java_suspend_self()`. This call will immediately return, won't it? Do you know what the purpose of this call was? The destructor of ThreadBlockInVM will block the current thread for the safepoint. So `java_suspend_self()` seems redundant.

I don't know.

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PR: https://git.openjdk.java.net/jdk/pull/3191