JDK-8255450: runtime/ThreadCountLimit.java causes high system load

[tstuefe]

Hi,

this is rather trivial:

runtime/ThreadCountLimit.java, introduced with JDK-8222671, caused problems on our test machines (JDK-8222671 is private and cannot be accessed from outside Oracle, so all I know comes from its review thread [1]).

The test creates massive amount of threads in order to hit some OS limit which would manifest as an OOM. This affects unrelated processes, unless the test is executed in a jail or with specific limits set.

This test probably should be executed with a specific limit, but for now lets mark it as @stress and remove it from tier1.

---

Progress

• Change must not contain extraneous whitespace
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Testing

	Linux x32	Linux x64	Windows x64	macOS x64
Build	✔️ (1/1 passed)	✔️ (5/5 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)
Test (tier1)		✔️ (9/9 passed)	⏳ (1/9 running)	✔️ (9/9 passed)

Issue

• JDK-8255450: runtime/ThreadCountLimit.java causes high system load

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/876/head:pull/876
$ git checkout pull/876

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (2bb13c6)

[shipilev]

This makes sense to me. On my TR 3970X with Linux x86_64 release, it peaks at 70G VIRT, 3G RSS, and fails half of the time. The test itself should probably made more resilient, but even then it does not look like tier1-grade test.

[openjdk]

@tstuefe This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8255450: runtime/ThreadCountLimit.java causes high system load

Reviewed-by: shade

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At the time when this comment was updated there had been 5 new commits pushed to the master branch:

• 504cb00: 8252113: Move jfr man page into jfr module
• 552192f: 8255305: Add Linux x86_32 tier1 to submit workflow
• 66a3917: 8255331: Problemlist java/foreign/TestMismatch.java on 32-bit platforms until JDK-8254162
• cf56c7e: 8254980: ZGC: ZHeapIterator visits armed nmethods with -XX:-ClassUnloading
• 18d9905: 8255342: Remove non-specified JVM checks on Classes with Record attributes

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[tstuefe]

Following the trivial rule I will integrate this patch.

/integrate

[openjdk]

@tstuefe Since your change was applied there have been 5 commits pushed to the master branch:

• 504cb00: 8252113: Move jfr man page into jfr module
• 552192f: 8255305: Add Linux x86_32 tier1 to submit workflow
• 66a3917: 8255331: Problemlist java/foreign/TestMismatch.java on 32-bit platforms until JDK-8254162
• cf56c7e: 8254980: ZGC: ZHeapIterator visits armed nmethods with -XX:-ClassUnloading
• 18d9905: 8255342: Remove non-specified JVM checks on Classes with Record attributes

Your commit was automatically rebased without conflicts.

Pushed as commit 7d41a54.

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