8307392: [Lilliput] Revert deflation of dead object's monitors

[rkennke]

In #28, I introduced some code that forces deflation of monitors on objects that are about to die. Discussions around a possible upstreaming of this code (openjdk/jdk#13721) comes to the conclusion that this should not be necessary, and indeed, I could not reproduce the original problem that I was having in Lilliput with the code removed. I assume some changes in upstream and/or Lilliput since then have fixed the root cause. Let's remove that code and see what explodes.

Testing: (All with -XX:+UseHeavyMonitors to amplify monitor traffic)

• hotspot_gc
• tier1
• tier2
• SPECjvm workloads

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Issue

• JDK-8307392: [Lilliput] Revert deflation of dead object's monitors

Reviewers

• Aleksey Shipilev (@shipilev - Committer)

Reviewing

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[bridgekeeper]

👋 Welcome back rkennke! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[mlbridge]

Webrevs

• 01: Full - Incremental (0a3ef027)
• 00: Full (f82d25e8)

[shipilev]

But we know this would not be safe without the GC threads rendezvous-ing, right? Also, this seems to include #90.

[rkennke]

But we know this would not be safe without the GC threads rendezvous-ing, right? Also, this seems to include #90.

Yes, but in Lilliput we rendezous GC threads since #27. This PR essentially reverts that earlier PR. I removed the Shenandoah part.

[shipilev]

Okay then!

[openjdk]

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8307392: [Lilliput] Revert deflation of dead object's monitors

Reviewed-by: shade

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[rkennke]

/integrate

[openjdk]

Going to push as commit e1d1a11.

[openjdk]

@rkennke Pushed as commit e1d1a11.

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