RFR: 8262454: Handshake timeout improvements, single target, kill unfinished thread

[David Holmes]

On Fri, 26 Feb 2021 10:48:14 GMT, Robbin Ehn <rehn at openjdk.org> wrote:

> When executing a single target handshake we do not have a timeout.
> When we timeout we should crash the thread with the non-completed handshake operation.
> 
> VM_Handshake only had one implementer so I remove it.
> 
> Passes t1-5.

Overall this looks good. I'll approve the final version.

Thanks,
David

src/hotspot/share/runtime/handshake.cpp line 197:

> 195: 
> 196:   if (target != NULL) {
> 197:     if (os::signal_thread(target, SIGILL, "cannot be handshaked")) {

Note this is a no-op on Windows. Not sure if you want to conditionalize this or not.

test/hotspot/jtreg/runtime/handshake/HandshakeTimeoutTest.java line 2:

> 1: /*
> 2:  * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.

2021

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PR: https://git.openjdk.java.net/jdk/pull/2743