8271060: Merge G1CollectedHeap::determine_start_concurrent_mark_gc and G1Policy::decide_on_conc_mark_initiation

[tschatzl]

Hi all,

can I have reviews for this merge of two methods that have the same purpose: determine whether this pause should be a concurrent start pause. The reason for this merge is that G1CollectedHeap::determine_start_concurrent_mark_gc just calls the other, and

• is the only caller
• only adds another condition of the same type that G1Policy::decide_on_conc_mark_initiation does at the beginning
• adds some return value checking and return value
  which all imho fit into G1Policy::decide_on_conc_mark_initiation too.

It also reduces G1CollectedHeap a bit. The main reason for me to put this in the new location is basically that that additional condition in G1CollectedHeap::determine_start_concurrent_mark_gc makes all conditions for that decision be located closer together.

If you think otherwise and this is a bad idea, I will close this PR.

Testing: manual gc/g1 runs

Thanks,
Thomas

---

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Issue

• JDK-8271060: Merge G1CollectedHeap::determine_start_concurrent_mark_gc and G1Policy::decide_on_conc_mark_initiation

Reviewers

• Albert Mingkun Yang (@albertnetymk - Committer) ⚠️ Review applies to bf8d44d
• Kim Barrett (@kimbarrett - Reviewer)

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[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (0393b5f2)
• 00: Full (bf8d44d1)

[albertnetymk]

bool should_start_concurrent_mark_operation = policy()->decide_on_concurrent_start_pause();

The name, decide_on_concurrent_start_pause(), is not very obvious, IMO; I feel it's because it's trying to do two things: 1. deciding the pause type, 2. returns whether the decided pause type is concurrent_start_gc.

I wonder if sth like the following (decoupling the two tasks) is clearer:

policy()->decide_pause_type();
bool should_start_concurrent_mark_operation = collector_state()->in_concurrent_start_gc();

Ofc, this is very subjective. The PR is fine as it is.

[tschatzl]

bool should_start_concurrent_mark_operation = policy()->decide_on_concurrent_start_pause();

The name, decide_on_concurrent_start_pause(), is not very obvious, IMO; I feel it's because it's trying to do two things: 1. deciding the pause type, 2. returns whether the decided pause type is concurrent_start_gc.

I wonder if sth like the following (decoupling the two tasks) is clearer:

policy()->decide_pause_type();
bool should_start_concurrent_mark_operation = collector_state()->in_concurrent_start_gc();

Ofc, this is very subjective. The PR is fine as it is.

Thanks for your review. I understand your concerns and will think about it. Are there any other opinions in that direction?

[tschatzl]

I updated the code according to @albertnetymk 's suggestions: I've been on the fence about this already anyway.

[kimbarrett]

Looks good.

[openjdk]

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

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

8271060: Merge G1CollectedHeap::determine_start_concurrent_mark_gc and G1Policy::decide_on_conc_mark_initiation

Reviewed-by: ayang, kbarrett

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At the time when this comment was updated there had been 2 new commits pushed to the master branch:

• d1257d5: 8271126: ProblemList runtime/InvocationTests/invokevirtualTests.java
• 50bb731: 8270286: com.sun.net.httpserver.spi.HttpServerProvider: remove use of deprecated API

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[tschatzl]

Thanks @kimbarrett and @albertnetymk for your reviews.

/integrate

[openjdk]

Going to push as commit ea182b5.
Since your change was applied there have been 26 commits pushed to the master branch:

• fb85960: 8271149: remove unreferenced functions from EncodingSupport_md.c
• 8156ff6: 8271147: java/nio/file/Path.java javadoc typo
• 9935440: Merge
• e3800e6: 8271162: runtime/StackTrace/LargeClassTest.java can be run in driver mode
• ee93cef: 8271158: runtime/handshake/HandshakeTimeoutTest.java test doesn't check exit code
• 84be910: 8271169: runtime/Safepoint/TestAbortVMOnSafepointTimeout.java can be run in driver mode
• 2d165a2: 8271160: runtime/jni/checked/TestCheckedJniExceptionCheck.java doesn't set -Djava.library.path
• 7165b3f: 8271155: Wrong path separator in env variable
• ecc37b0: 8270916: Update java.lang.annotation.Target for changes in JLS 9.6.4.1
• 4812e53: 8271094: runtime/duplAttributes/DuplAttributesTest.java doesn't check exit code
• ... and 16 more: https://git.openjdk.java.net/jdk/compare/9131a8f5f241b04c28a875fddb7a060cc9a3c252...master

Your commit was automatically rebased without conflicts.

[openjdk]

@tschatzl Pushed as commit ea182b5.

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